4 TGSI, Tungsten Graphics Shader Infrastructure, is an intermediate language
5 for describing shaders. Since Gallium is inherently shaderful, shaders are
6 an important part of the API. TGSI is the only intermediate representation
12 All TGSI instructions, known as *opcodes*, operate on arbitrary-precision
13 floating-point four-component vectors. An opcode may have up to one
14 destination register, known as *dst*, and between zero and three source
15 registers, called *src0* through *src2*, or simply *src* if there is only
18 Some instructions, like :opcode:`I2F`, permit re-interpretation of vector
19 components as integers. Other instructions permit using registers as
20 two-component vectors with double precision; see :ref:`doubleopcodes`.
22 When an instruction has a scalar result, the result is usually copied into
23 each of the components of *dst*. When this happens, the result is said to be
24 *replicated* to *dst*. :opcode:`RCP` is one such instruction.
29 TGSI supports 32-bit negate and absolute value modifiers on floating-point
30 inputs, and 32-bit integer negates on some drivers. The negate applies after
31 absolute value if both are present.
33 The type of an input can be found by ``tgsi_opcode_infer_src_type()``, and
34 TGSI_OPCODE_MOV and the second and third operands of TGSI_OPCODE_UCMP (which
35 return TGSI_TYPE_UNTYPED) are also considered floats for the purpose of source
42 The saturate modifier clamps 32-bit destination stores to [0.0, 1.0].
44 For arithmetic instruction having a precise modifier certain optimizations
45 which may alter the result are disallowed. Example: *add(mul(a,b),c)* can't be
46 optimized to TGSI_OPCODE_MAD, because some hardware only supports the fused
53 ^^^^^^^^^^^^^^^^^^^^^^^^^
55 These opcodes are guaranteed to be available regardless of the driver being
58 .. opcode:: ARL - Address Register Load
62 dst.x = (int) \lfloor src.x\rfloor
64 dst.y = (int) \lfloor src.y\rfloor
66 dst.z = (int) \lfloor src.z\rfloor
68 dst.w = (int) \lfloor src.w\rfloor
71 .. opcode:: MOV - Move
84 .. opcode:: LIT - Light Coefficients
89 dst.y &= max(src.x, 0) \\
90 dst.z &= (src.x > 0) ? max(src.y, 0)^{clamp(src.w, -128, 128))} : 0 \\
94 .. opcode:: RCP - Reciprocal
96 This instruction replicates its result.
100 dst = \frac{1}{src.x}
103 .. opcode:: RSQ - Reciprocal Square Root
105 This instruction replicates its result. The results are undefined for *src* <= 0.
109 dst = \frac{1}{\sqrt{src.x}}
112 .. opcode:: SQRT - Square Root
114 This instruction replicates its result. The results are undefined for *src* < 0.
121 .. opcode:: EXP - Approximate Exponential Base 2
125 dst.x &= 2^{\lfloor src.x\rfloor} \\
126 dst.y &= src.x - \lfloor src.x\rfloor \\
127 dst.z &= 2^{src.x} \\
131 .. opcode:: LOG - Approximate Logarithm Base 2
135 dst.x &= \lfloor\log_2{|src.x|}\rfloor \\
136 dst.y &= \frac{|src.x|}{2^{\lfloor\log_2{|src.x|}\rfloor}} \\
137 dst.z &= \log_2{|src.x|} \\
141 .. opcode:: MUL - Multiply
145 dst.x = src0.x \times src1.x
147 dst.y = src0.y \times src1.y
149 dst.z = src0.z \times src1.z
151 dst.w = src0.w \times src1.w
154 .. opcode:: ADD - Add
158 dst.x = src0.x + src1.x
160 dst.y = src0.y + src1.y
162 dst.z = src0.z + src1.z
164 dst.w = src0.w + src1.w
167 .. opcode:: DP3 - 3-component Dot Product
169 This instruction replicates its result.
173 dst = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z
176 .. opcode:: DP4 - 4-component Dot Product
178 This instruction replicates its result.
182 dst = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z + src0.w \times src1.w
185 .. opcode:: DST - Distance Vector
190 dst.y &= src0.y \times src1.y\\
195 .. opcode:: MIN - Minimum
199 dst.x = min(src0.x, src1.x)
201 dst.y = min(src0.y, src1.y)
203 dst.z = min(src0.z, src1.z)
205 dst.w = min(src0.w, src1.w)
208 .. opcode:: MAX - Maximum
212 dst.x = max(src0.x, src1.x)
214 dst.y = max(src0.y, src1.y)
216 dst.z = max(src0.z, src1.z)
218 dst.w = max(src0.w, src1.w)
221 .. opcode:: SLT - Set On Less Than
225 dst.x = (src0.x < src1.x) ? 1.0F : 0.0F
227 dst.y = (src0.y < src1.y) ? 1.0F : 0.0F
229 dst.z = (src0.z < src1.z) ? 1.0F : 0.0F
231 dst.w = (src0.w < src1.w) ? 1.0F : 0.0F
234 .. opcode:: SGE - Set On Greater Equal Than
238 dst.x = (src0.x >= src1.x) ? 1.0F : 0.0F
240 dst.y = (src0.y >= src1.y) ? 1.0F : 0.0F
242 dst.z = (src0.z >= src1.z) ? 1.0F : 0.0F
244 dst.w = (src0.w >= src1.w) ? 1.0F : 0.0F
247 .. opcode:: MAD - Multiply And Add
249 Perform a * b + c. The implementation is free to decide whether there is an
250 intermediate rounding step or not.
254 dst.x = src0.x \times src1.x + src2.x
256 dst.y = src0.y \times src1.y + src2.y
258 dst.z = src0.z \times src1.z + src2.z
260 dst.w = src0.w \times src1.w + src2.w
263 .. opcode:: LRP - Linear Interpolate
267 dst.x = src0.x \times src1.x + (1 - src0.x) \times src2.x
269 dst.y = src0.y \times src1.y + (1 - src0.y) \times src2.y
271 dst.z = src0.z \times src1.z + (1 - src0.z) \times src2.z
273 dst.w = src0.w \times src1.w + (1 - src0.w) \times src2.w
276 .. opcode:: FMA - Fused Multiply-Add
278 Perform a * b + c with no intermediate rounding step.
282 dst.x = src0.x \times src1.x + src2.x
284 dst.y = src0.y \times src1.y + src2.y
286 dst.z = src0.z \times src1.z + src2.z
288 dst.w = src0.w \times src1.w + src2.w
291 .. opcode:: FRC - Fraction
295 dst.x = src.x - \lfloor src.x\rfloor
297 dst.y = src.y - \lfloor src.y\rfloor
299 dst.z = src.z - \lfloor src.z\rfloor
301 dst.w = src.w - \lfloor src.w\rfloor
304 .. opcode:: FLR - Floor
308 dst.x = \lfloor src.x\rfloor
310 dst.y = \lfloor src.y\rfloor
312 dst.z = \lfloor src.z\rfloor
314 dst.w = \lfloor src.w\rfloor
317 .. opcode:: ROUND - Round
330 .. opcode:: EX2 - Exponential Base 2
332 This instruction replicates its result.
339 .. opcode:: LG2 - Logarithm Base 2
341 This instruction replicates its result.
348 .. opcode:: POW - Power
350 This instruction replicates its result.
354 dst = src0.x^{src1.x}
357 .. opcode:: LDEXP - Multiply Number by Integral Power of 2
359 *src1* is an integer.
363 dst.x = src0.x * 2^{src1.x}
364 dst.y = src0.y * 2^{src1.y}
365 dst.z = src0.z * 2^{src1.z}
366 dst.w = src0.w * 2^{src1.w}
369 .. opcode:: COS - Cosine
371 This instruction replicates its result.
378 .. opcode:: DDX, DDX_FINE - Derivative Relative To X
380 The fine variant is only used when ``PIPE_CAP_FS_FINE_DERIVATIVE`` is
381 advertised. When it is, the fine version guarantees one derivative per row
382 while DDX is allowed to be the same for the entire 2x2 quad.
386 dst.x = partialx(src.x)
388 dst.y = partialx(src.y)
390 dst.z = partialx(src.z)
392 dst.w = partialx(src.w)
395 .. opcode:: DDY, DDY_FINE - Derivative Relative To Y
397 The fine variant is only used when ``PIPE_CAP_FS_FINE_DERIVATIVE`` is
398 advertised. When it is, the fine version guarantees one derivative per column
399 while DDY is allowed to be the same for the entire 2x2 quad.
403 dst.x = partialy(src.x)
405 dst.y = partialy(src.y)
407 dst.z = partialy(src.z)
409 dst.w = partialy(src.w)
412 .. opcode:: PK2H - Pack Two 16-bit Floats
414 This instruction replicates its result.
418 dst = f32\_to\_f16(src.x) | f32\_to\_f16(src.y) << 16
421 .. opcode:: PK2US - Pack Two Unsigned 16-bit Scalars
423 This instruction replicates its result.
427 dst = f32\_to\_unorm16(src.x) | f32\_to\_unorm16(src.y) << 16
430 .. opcode:: PK4B - Pack Four Signed 8-bit Scalars
432 This instruction replicates its result.
436 dst = f32\_to\_snorm8(src.x) |
437 (f32\_to\_snorm8(src.y) << 8) |
438 (f32\_to\_snorm8(src.z) << 16) |
439 (f32\_to\_snorm8(src.w) << 24)
442 .. opcode:: PK4UB - Pack Four Unsigned 8-bit Scalars
444 This instruction replicates its result.
448 dst = f32\_to\_unorm8(src.x) |
449 (f32\_to\_unorm8(src.y) << 8) |
450 (f32\_to\_unorm8(src.z) << 16) |
451 (f32\_to\_unorm8(src.w) << 24)
454 .. opcode:: SEQ - Set On Equal
458 dst.x = (src0.x == src1.x) ? 1.0F : 0.0F
460 dst.y = (src0.y == src1.y) ? 1.0F : 0.0F
462 dst.z = (src0.z == src1.z) ? 1.0F : 0.0F
464 dst.w = (src0.w == src1.w) ? 1.0F : 0.0F
467 .. opcode:: SGT - Set On Greater Than
471 dst.x = (src0.x > src1.x) ? 1.0F : 0.0F
473 dst.y = (src0.y > src1.y) ? 1.0F : 0.0F
475 dst.z = (src0.z > src1.z) ? 1.0F : 0.0F
477 dst.w = (src0.w > src1.w) ? 1.0F : 0.0F
480 .. opcode:: SIN - Sine
482 This instruction replicates its result.
489 .. opcode:: SLE - Set On Less Equal Than
493 dst.x = (src0.x <= src1.x) ? 1.0F : 0.0F
495 dst.y = (src0.y <= src1.y) ? 1.0F : 0.0F
497 dst.z = (src0.z <= src1.z) ? 1.0F : 0.0F
499 dst.w = (src0.w <= src1.w) ? 1.0F : 0.0F
502 .. opcode:: SNE - Set On Not Equal
506 dst.x = (src0.x != src1.x) ? 1.0F : 0.0F
508 dst.y = (src0.y != src1.y) ? 1.0F : 0.0F
510 dst.z = (src0.z != src1.z) ? 1.0F : 0.0F
512 dst.w = (src0.w != src1.w) ? 1.0F : 0.0F
515 .. opcode:: TEX - Texture Lookup
517 for array textures *src0.y* contains the slice for 1D,
518 and *src0.z* contain the slice for 2D.
520 for shadow textures with no arrays (and not cube map),
521 *src0.z* contains the reference value.
523 for shadow textures with arrays, *src0.z* contains
524 the reference value for 1D arrays, and *src0.w* contains
525 the reference value for 2D arrays and cube maps.
527 for cube map array shadow textures, the reference value
528 cannot be passed in *src0.w*, and TEX2 must be used instead.
534 shadow_ref = src0.z or src0.w (optional)
538 dst = texture\_sample(unit, coord, shadow_ref)
541 .. opcode:: TEX2 - Texture Lookup (for shadow cube map arrays only)
543 this is the same as TEX, but uses another reg to encode the
554 dst = texture\_sample(unit, coord, shadow_ref)
559 .. opcode:: TXD - Texture Lookup with Derivatives
571 dst = texture\_sample\_deriv(unit, coord, ddx, ddy)
574 .. opcode:: TXP - Projective Texture Lookup
578 coord.x = src0.x / src0.w
580 coord.y = src0.y / src0.w
582 coord.z = src0.z / src0.w
588 dst = texture\_sample(unit, coord)
591 .. opcode:: UP2H - Unpack Two 16-Bit Floats
595 dst.x = f16\_to\_f32(src0.x \& 0xffff)
597 dst.y = f16\_to\_f32(src0.x >> 16)
599 dst.z = f16\_to\_f32(src0.x \& 0xffff)
601 dst.w = f16\_to\_f32(src0.x >> 16)
605 Considered for removal.
607 .. opcode:: UP2US - Unpack Two Unsigned 16-Bit Scalars
613 Considered for removal.
615 .. opcode:: UP4B - Unpack Four Signed 8-Bit Values
621 Considered for removal.
623 .. opcode:: UP4UB - Unpack Four Unsigned 8-Bit Scalars
629 Considered for removal.
632 .. opcode:: ARR - Address Register Load With Round
636 dst.x = (int) round(src.x)
638 dst.y = (int) round(src.y)
640 dst.z = (int) round(src.z)
642 dst.w = (int) round(src.w)
645 .. opcode:: SSG - Set Sign
649 dst.x = (src.x > 0) ? 1 : (src.x < 0) ? -1 : 0
651 dst.y = (src.y > 0) ? 1 : (src.y < 0) ? -1 : 0
653 dst.z = (src.z > 0) ? 1 : (src.z < 0) ? -1 : 0
655 dst.w = (src.w > 0) ? 1 : (src.w < 0) ? -1 : 0
658 .. opcode:: CMP - Compare
662 dst.x = (src0.x < 0) ? src1.x : src2.x
664 dst.y = (src0.y < 0) ? src1.y : src2.y
666 dst.z = (src0.z < 0) ? src1.z : src2.z
668 dst.w = (src0.w < 0) ? src1.w : src2.w
671 .. opcode:: KILL_IF - Conditional Discard
673 Conditional discard. Allowed in fragment shaders only.
677 if (src.x < 0 || src.y < 0 || src.z < 0 || src.w < 0)
682 .. opcode:: KILL - Discard
684 Unconditional discard. Allowed in fragment shaders only.
687 .. opcode:: DEMOTE - Demote Invocation to a Helper
689 This demotes the current invocation to a helper, but continues
690 execution (while KILL may or may not terminate the
691 invocation). After this runs, all the usual helper invocation rules
692 apply about discarding buffer and render target writes. This is
693 useful for having accurate derivatives in the other invocations
694 which have not been demoted.
696 Allowed in fragment shaders only.
699 .. opcode:: READ_HELPER - Reads Invocation Helper Status
701 This is identical to ``TGSI_SEMANTIC_HELPER_INVOCATION``, except
702 this will read the current value, which might change as a result of
703 a ``DEMOTE`` instruction.
705 Allowed in fragment shaders only.
708 .. opcode:: TXB - Texture Lookup With Bias
710 for cube map array textures and shadow cube maps, the bias value
711 cannot be passed in *src0.w*, and TXB2 must be used instead.
713 if the target is a shadow texture, the reference value is always
714 in *src.z* (this prevents shadow 3d and shadow 2d arrays from
715 using this instruction, but this is not needed).
731 dst = texture\_sample(unit, coord, bias)
734 .. opcode:: TXB2 - Texture Lookup With Bias (some cube maps only)
736 this is the same as TXB, but uses another reg to encode the
737 LOD bias value for cube map arrays and shadow cube maps.
738 Presumably shadow 2d arrays and shadow 3d targets could use
739 this encoding too, but this is not legal.
741 if the target is a shadow cube map array, the reference value is in
752 dst = texture\_sample(unit, coord, bias)
755 .. opcode:: DIV - Divide
759 dst.x = \frac{src0.x}{src1.x}
761 dst.y = \frac{src0.y}{src1.y}
763 dst.z = \frac{src0.z}{src1.z}
765 dst.w = \frac{src0.w}{src1.w}
768 .. opcode:: DP2 - 2-component Dot Product
770 This instruction replicates its result.
774 dst = src0.x \times src1.x + src0.y \times src1.y
777 .. opcode:: TEX_LZ - Texture Lookup With LOD = 0
779 This is the same as TXL with LOD = 0. Like every texture opcode, it obeys
780 pipe_sampler_view::u.tex.first_level and pipe_sampler_state::min_lod.
781 There is no way to override those two in shaders.
797 dst = texture\_sample(unit, coord, lod)
800 .. opcode:: TXL - Texture Lookup With explicit LOD
802 for cube map array textures, the explicit LOD value
803 cannot be passed in *src0.w*, and TXL2 must be used instead.
805 if the target is a shadow texture, the reference value is always
806 in *src.z* (this prevents shadow 3d / 2d array / cube targets from
807 using this instruction, but this is not needed).
823 dst = texture\_sample(unit, coord, lod)
826 .. opcode:: TXL2 - Texture Lookup With explicit LOD (for cube map arrays only)
828 this is the same as TXL, but uses another reg to encode the
830 Presumably shadow 3d / 2d array / cube targets could use
831 this encoding too, but this is not legal.
833 if the target is a shadow cube map array, the reference value is in
844 dst = texture\_sample(unit, coord, lod)
848 ^^^^^^^^^^^^^^^^^^^^^^^^
850 These opcodes are primarily provided for special-use computational shaders.
851 Support for these opcodes indicated by a special pipe capability bit (TBD).
853 XXX doesn't look like most of the opcodes really belong here.
855 .. opcode:: CEIL - Ceiling
859 dst.x = \lceil src.x\rceil
861 dst.y = \lceil src.y\rceil
863 dst.z = \lceil src.z\rceil
865 dst.w = \lceil src.w\rceil
868 .. opcode:: TRUNC - Truncate
881 .. opcode:: MOD - Modulus
885 dst.x = src0.x \bmod src1.x
887 dst.y = src0.y \bmod src1.y
889 dst.z = src0.z \bmod src1.z
891 dst.w = src0.w \bmod src1.w
894 .. opcode:: UARL - Integer Address Register Load
896 Moves the contents of the source register, assumed to be an integer, into the
897 destination register, which is assumed to be an address (ADDR) register.
900 .. opcode:: TXF - Texel Fetch
902 As per NV_gpu_shader4, extract a single texel from a specified texture
903 image or PIPE_BUFFER resource. The source sampler may not be a CUBE or
905 four-component signed integer vector used to identify the single texel
906 accessed. 3 components + level. If the texture is multisampled, then
907 the fourth component indicates the sample, not the mipmap level.
908 Just like texture instructions, an optional
909 offset vector is provided, which is subject to various driver restrictions
910 (regarding range, source of offsets). This instruction ignores the sampler
913 TXF(uint_vec coord, int_vec offset).
916 .. opcode:: TXQ - Texture Size Query
918 As per NV_gpu_program4, retrieve the dimensions of the texture depending on
919 the target. For 1D (width), 2D/RECT/CUBE (width, height), 3D (width, height,
920 depth), 1D array (width, layers), 2D array (width, height, layers).
921 Also return the number of accessible levels (last_level - first_level + 1)
924 For components which don't return a resource dimension, their value
931 dst.x = texture\_width(unit, lod)
933 dst.y = texture\_height(unit, lod)
935 dst.z = texture\_depth(unit, lod)
937 dst.w = texture\_levels(unit)
940 .. opcode:: TXQS - Texture Samples Query
942 This retrieves the number of samples in the texture, and stores it
943 into the x component as an unsigned integer. The other components are
944 undefined. If the texture is not multisampled, this function returns
945 (1, undef, undef, undef).
949 dst.x = texture\_samples(unit)
952 .. opcode:: TG4 - Texture Gather
954 As per ARB_texture_gather, gathers the four texels to be used in a bi-linear
955 filtering operation and packs them into a single register. Only works with
956 2D, 2D array, cubemaps, and cubemaps arrays. For 2D textures, only the
957 addressing modes of the sampler and the top level of any mip pyramid are
958 used. Set W to zero. It behaves like the TEX instruction, but a filtered
959 sample is not generated. The four samples that contribute to filtering are
960 placed into XYZW in clockwise order, starting with the (u,v) texture
961 coordinate delta at the following locations (-, +), (+, +), (+, -), (-, -),
962 where the magnitude of the deltas are half a texel.
964 PIPE_CAP_TEXTURE_SM5 enhances this instruction to support shadow per-sample
965 depth compares, single component selection, and a non-constant offset. It
966 doesn't allow support for the GL independent offset to get i0,j0. This would
967 require another CAP is HW can do it natively. For now we lower that before
970 PIPE_CAP_TGSI_TG4_COMPONENT_IN_SWIZZLE changes the encoding so that component
971 is stored in the sampler source swizzle x.
977 (without TGSI_TG4_COMPONENT_IN_SWIZZLE)
980 dst = texture\_gather4 (unit, coord, component)
982 (with TGSI_TG4_COMPONENT_IN_SWIZZLE)
983 dst = texture\_gather4 (unit, coord)
984 component is encoded in sampler swizzle.
986 (with SM5 - cube array shadow)
994 dst = texture\_gather (uint, coord, compare)
996 .. opcode:: LODQ - level of detail query
998 Compute the LOD information that the texture pipe would use to access the
999 texture. The Y component contains the computed LOD lambda_prime. The X
1000 component contains the LOD that will be accessed, based on min/max LODs
1007 dst.xy = lodq(uint, coord);
1009 .. opcode:: CLOCK - retrieve the current shader time
1011 Invoking this instruction multiple times in the same shader should
1012 cause monotonically increasing values to be returned. The values
1013 are implicitly 64-bit, so if fewer than 64 bits of precision are
1014 available, to provide expected wraparound semantics, the value
1015 should be shifted up so that the most significant bit of the time
1016 is the most significant bit of the 64-bit value.
1024 ^^^^^^^^^^^^^^^^^^^^^^^^
1025 These opcodes are used for integer operations.
1026 Support for these opcodes indicated by PIPE_SHADER_CAP_INTEGERS (all of them?)
1029 .. opcode:: I2F - Signed Integer To Float
1031 Rounding is unspecified (round to nearest even suggested).
1035 dst.x = (float) src.x
1037 dst.y = (float) src.y
1039 dst.z = (float) src.z
1041 dst.w = (float) src.w
1044 .. opcode:: U2F - Unsigned Integer To Float
1046 Rounding is unspecified (round to nearest even suggested).
1050 dst.x = (float) src.x
1052 dst.y = (float) src.y
1054 dst.z = (float) src.z
1056 dst.w = (float) src.w
1059 .. opcode:: F2I - Float to Signed Integer
1061 Rounding is towards zero (truncate).
1062 Values outside signed range (including NaNs) produce undefined results.
1075 .. opcode:: F2U - Float to Unsigned Integer
1077 Rounding is towards zero (truncate).
1078 Values outside unsigned range (including NaNs) produce undefined results.
1082 dst.x = (unsigned) src.x
1084 dst.y = (unsigned) src.y
1086 dst.z = (unsigned) src.z
1088 dst.w = (unsigned) src.w
1091 .. opcode:: UADD - Integer Add
1093 This instruction works the same for signed and unsigned integers.
1094 The low 32bit of the result is returned.
1098 dst.x = src0.x + src1.x
1100 dst.y = src0.y + src1.y
1102 dst.z = src0.z + src1.z
1104 dst.w = src0.w + src1.w
1107 .. opcode:: UMAD - Integer Multiply And Add
1109 This instruction works the same for signed and unsigned integers.
1110 The multiplication returns the low 32bit (as does the result itself).
1114 dst.x = src0.x \times src1.x + src2.x
1116 dst.y = src0.y \times src1.y + src2.y
1118 dst.z = src0.z \times src1.z + src2.z
1120 dst.w = src0.w \times src1.w + src2.w
1123 .. opcode:: UMUL - Integer Multiply
1125 This instruction works the same for signed and unsigned integers.
1126 The low 32bit of the result is returned.
1130 dst.x = src0.x \times src1.x
1132 dst.y = src0.y \times src1.y
1134 dst.z = src0.z \times src1.z
1136 dst.w = src0.w \times src1.w
1139 .. opcode:: IMUL_HI - Signed Integer Multiply High Bits
1141 The high 32bits of the multiplication of 2 signed integers are returned.
1145 dst.x = (src0.x \times src1.x) >> 32
1147 dst.y = (src0.y \times src1.y) >> 32
1149 dst.z = (src0.z \times src1.z) >> 32
1151 dst.w = (src0.w \times src1.w) >> 32
1154 .. opcode:: UMUL_HI - Unsigned Integer Multiply High Bits
1156 The high 32bits of the multiplication of 2 unsigned integers are returned.
1160 dst.x = (src0.x \times src1.x) >> 32
1162 dst.y = (src0.y \times src1.y) >> 32
1164 dst.z = (src0.z \times src1.z) >> 32
1166 dst.w = (src0.w \times src1.w) >> 32
1169 .. opcode:: IDIV - Signed Integer Division
1171 TBD: behavior for division by zero.
1175 dst.x = \frac{src0.x}{src1.x}
1177 dst.y = \frac{src0.y}{src1.y}
1179 dst.z = \frac{src0.z}{src1.z}
1181 dst.w = \frac{src0.w}{src1.w}
1184 .. opcode:: UDIV - Unsigned Integer Division
1186 For division by zero, 0xffffffff is returned.
1190 dst.x = \frac{src0.x}{src1.x}
1192 dst.y = \frac{src0.y}{src1.y}
1194 dst.z = \frac{src0.z}{src1.z}
1196 dst.w = \frac{src0.w}{src1.w}
1199 .. opcode:: UMOD - Unsigned Integer Remainder
1201 If *src1* is zero, 0xffffffff is returned.
1205 dst.x = src0.x \bmod src1.x
1207 dst.y = src0.y \bmod src1.y
1209 dst.z = src0.z \bmod src1.z
1211 dst.w = src0.w \bmod src1.w
1214 .. opcode:: NOT - Bitwise Not
1227 .. opcode:: AND - Bitwise And
1231 dst.x = src0.x \& src1.x
1233 dst.y = src0.y \& src1.y
1235 dst.z = src0.z \& src1.z
1237 dst.w = src0.w \& src1.w
1240 .. opcode:: OR - Bitwise Or
1244 dst.x = src0.x | src1.x
1246 dst.y = src0.y | src1.y
1248 dst.z = src0.z | src1.z
1250 dst.w = src0.w | src1.w
1253 .. opcode:: XOR - Bitwise Xor
1257 dst.x = src0.x \oplus src1.x
1259 dst.y = src0.y \oplus src1.y
1261 dst.z = src0.z \oplus src1.z
1263 dst.w = src0.w \oplus src1.w
1266 .. opcode:: IMAX - Maximum of Signed Integers
1270 dst.x = max(src0.x, src1.x)
1272 dst.y = max(src0.y, src1.y)
1274 dst.z = max(src0.z, src1.z)
1276 dst.w = max(src0.w, src1.w)
1279 .. opcode:: UMAX - Maximum of Unsigned Integers
1283 dst.x = max(src0.x, src1.x)
1285 dst.y = max(src0.y, src1.y)
1287 dst.z = max(src0.z, src1.z)
1289 dst.w = max(src0.w, src1.w)
1292 .. opcode:: IMIN - Minimum of Signed Integers
1296 dst.x = min(src0.x, src1.x)
1298 dst.y = min(src0.y, src1.y)
1300 dst.z = min(src0.z, src1.z)
1302 dst.w = min(src0.w, src1.w)
1305 .. opcode:: UMIN - Minimum of Unsigned Integers
1309 dst.x = min(src0.x, src1.x)
1311 dst.y = min(src0.y, src1.y)
1313 dst.z = min(src0.z, src1.z)
1315 dst.w = min(src0.w, src1.w)
1318 .. opcode:: SHL - Shift Left
1320 The shift count is masked with 0x1f before the shift is applied.
1324 dst.x = src0.x << (0x1f \& src1.x)
1326 dst.y = src0.y << (0x1f \& src1.y)
1328 dst.z = src0.z << (0x1f \& src1.z)
1330 dst.w = src0.w << (0x1f \& src1.w)
1333 .. opcode:: ISHR - Arithmetic Shift Right (of Signed Integer)
1335 The shift count is masked with 0x1f before the shift is applied.
1339 dst.x = src0.x >> (0x1f \& src1.x)
1341 dst.y = src0.y >> (0x1f \& src1.y)
1343 dst.z = src0.z >> (0x1f \& src1.z)
1345 dst.w = src0.w >> (0x1f \& src1.w)
1348 .. opcode:: USHR - Logical Shift Right
1350 The shift count is masked with 0x1f before the shift is applied.
1354 dst.x = src0.x >> (unsigned) (0x1f \& src1.x)
1356 dst.y = src0.y >> (unsigned) (0x1f \& src1.y)
1358 dst.z = src0.z >> (unsigned) (0x1f \& src1.z)
1360 dst.w = src0.w >> (unsigned) (0x1f \& src1.w)
1363 .. opcode:: UCMP - Integer Conditional Move
1367 dst.x = src0.x ? src1.x : src2.x
1369 dst.y = src0.y ? src1.y : src2.y
1371 dst.z = src0.z ? src1.z : src2.z
1373 dst.w = src0.w ? src1.w : src2.w
1377 .. opcode:: ISSG - Integer Set Sign
1381 dst.x = (src0.x < 0) ? -1 : (src0.x > 0) ? 1 : 0
1383 dst.y = (src0.y < 0) ? -1 : (src0.y > 0) ? 1 : 0
1385 dst.z = (src0.z < 0) ? -1 : (src0.z > 0) ? 1 : 0
1387 dst.w = (src0.w < 0) ? -1 : (src0.w > 0) ? 1 : 0
1391 .. opcode:: FSLT - Float Set On Less Than (ordered)
1393 Same comparison as SLT but returns integer instead of 1.0/0.0 float
1397 dst.x = (src0.x < src1.x) ? \sim 0 : 0
1399 dst.y = (src0.y < src1.y) ? \sim 0 : 0
1401 dst.z = (src0.z < src1.z) ? \sim 0 : 0
1403 dst.w = (src0.w < src1.w) ? \sim 0 : 0
1406 .. opcode:: ISLT - Signed Integer Set On Less Than
1410 dst.x = (src0.x < src1.x) ? \sim 0 : 0
1412 dst.y = (src0.y < src1.y) ? \sim 0 : 0
1414 dst.z = (src0.z < src1.z) ? \sim 0 : 0
1416 dst.w = (src0.w < src1.w) ? \sim 0 : 0
1419 .. opcode:: USLT - Unsigned Integer Set On Less Than
1423 dst.x = (src0.x < src1.x) ? \sim 0 : 0
1425 dst.y = (src0.y < src1.y) ? \sim 0 : 0
1427 dst.z = (src0.z < src1.z) ? \sim 0 : 0
1429 dst.w = (src0.w < src1.w) ? \sim 0 : 0
1432 .. opcode:: FSGE - Float Set On Greater Equal Than (ordered)
1434 Same comparison as SGE but returns integer instead of 1.0/0.0 float
1438 dst.x = (src0.x >= src1.x) ? \sim 0 : 0
1440 dst.y = (src0.y >= src1.y) ? \sim 0 : 0
1442 dst.z = (src0.z >= src1.z) ? \sim 0 : 0
1444 dst.w = (src0.w >= src1.w) ? \sim 0 : 0
1447 .. opcode:: ISGE - Signed Integer Set On Greater Equal Than
1451 dst.x = (src0.x >= src1.x) ? \sim 0 : 0
1453 dst.y = (src0.y >= src1.y) ? \sim 0 : 0
1455 dst.z = (src0.z >= src1.z) ? \sim 0 : 0
1457 dst.w = (src0.w >= src1.w) ? \sim 0 : 0
1460 .. opcode:: USGE - Unsigned Integer Set On Greater Equal Than
1464 dst.x = (src0.x >= src1.x) ? \sim 0 : 0
1466 dst.y = (src0.y >= src1.y) ? \sim 0 : 0
1468 dst.z = (src0.z >= src1.z) ? \sim 0 : 0
1470 dst.w = (src0.w >= src1.w) ? \sim 0 : 0
1473 .. opcode:: FSEQ - Float Set On Equal (ordered)
1475 Same comparison as SEQ but returns integer instead of 1.0/0.0 float
1479 dst.x = (src0.x == src1.x) ? \sim 0 : 0
1481 dst.y = (src0.y == src1.y) ? \sim 0 : 0
1483 dst.z = (src0.z == src1.z) ? \sim 0 : 0
1485 dst.w = (src0.w == src1.w) ? \sim 0 : 0
1488 .. opcode:: USEQ - Integer Set On Equal
1492 dst.x = (src0.x == src1.x) ? \sim 0 : 0
1494 dst.y = (src0.y == src1.y) ? \sim 0 : 0
1496 dst.z = (src0.z == src1.z) ? \sim 0 : 0
1498 dst.w = (src0.w == src1.w) ? \sim 0 : 0
1501 .. opcode:: FSNE - Float Set On Not Equal (unordered)
1503 Same comparison as SNE but returns integer instead of 1.0/0.0 float
1507 dst.x = (src0.x != src1.x) ? \sim 0 : 0
1509 dst.y = (src0.y != src1.y) ? \sim 0 : 0
1511 dst.z = (src0.z != src1.z) ? \sim 0 : 0
1513 dst.w = (src0.w != src1.w) ? \sim 0 : 0
1516 .. opcode:: USNE - Integer Set On Not Equal
1520 dst.x = (src0.x != src1.x) ? \sim 0 : 0
1522 dst.y = (src0.y != src1.y) ? \sim 0 : 0
1524 dst.z = (src0.z != src1.z) ? \sim 0 : 0
1526 dst.w = (src0.w != src1.w) ? \sim 0 : 0
1529 .. opcode:: INEG - Integer Negate
1544 .. opcode:: IABS - Integer Absolute Value
1558 These opcodes are used for bit-level manipulation of integers.
1560 .. opcode:: IBFE - Signed Bitfield Extract
1562 Like GLSL bitfieldExtract. Extracts a set of bits from the input, and
1563 sign-extends them if the high bit of the extracted window is set.
1567 def ibfe(value, offset, bits):
1568 if offset < 0 or bits < 0 or offset + bits > 32:
1570 if bits == 0: return 0
1571 # Note: >> sign-extends
1572 return (value << (32 - offset - bits)) >> (32 - bits)
1574 .. opcode:: UBFE - Unsigned Bitfield Extract
1576 Like GLSL bitfieldExtract. Extracts a set of bits from the input, without
1581 def ubfe(value, offset, bits):
1582 if offset < 0 or bits < 0 or offset + bits > 32:
1584 if bits == 0: return 0
1585 # Note: >> does not sign-extend
1586 return (value << (32 - offset - bits)) >> (32 - bits)
1588 .. opcode:: BFI - Bitfield Insert
1590 Like GLSL bitfieldInsert. Replaces a bit region of 'base' with the low bits
1595 def bfi(base, insert, offset, bits):
1596 if offset < 0 or bits < 0 or offset + bits > 32:
1598 # << defined such that mask == ~0 when bits == 32, offset == 0
1599 mask = ((1 << bits) - 1) << offset
1600 return ((insert << offset) & mask) | (base & ~mask)
1602 .. opcode:: BREV - Bitfield Reverse
1604 See SM5 instruction BFREV. Reverses the bits of the argument.
1606 .. opcode:: POPC - Population Count
1608 See SM5 instruction COUNTBITS. Counts the number of set bits in the argument.
1610 .. opcode:: LSB - Index of lowest set bit
1612 See SM5 instruction FIRSTBIT_LO. Computes the 0-based index of the first set
1613 bit of the argument. Returns -1 if none are set.
1615 .. opcode:: IMSB - Index of highest non-sign bit
1617 See SM5 instruction FIRSTBIT_SHI. Computes the 0-based index of the highest
1618 non-sign bit of the argument (i.e. highest 0 bit for negative numbers,
1619 highest 1 bit for positive numbers). Returns -1 if all bits are the same
1620 (i.e. for inputs 0 and -1).
1622 .. opcode:: UMSB - Index of highest set bit
1624 See SM5 instruction FIRSTBIT_HI. Computes the 0-based index of the highest
1625 set bit of the argument. Returns -1 if none are set.
1628 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
1630 These opcodes are only supported in geometry shaders; they have no meaning
1631 in any other type of shader.
1633 .. opcode:: EMIT - Emit
1635 Generate a new vertex for the current primitive into the specified vertex
1636 stream using the values in the output registers.
1639 .. opcode:: ENDPRIM - End Primitive
1641 Complete the current primitive in the specified vertex stream (consisting of
1642 the emitted vertices), and start a new one.
1648 These opcodes are part of :term:`GLSL`'s opcode set. Support for these
1649 opcodes is determined by a special capability bit, ``GLSL``.
1650 Some require glsl version 1.30 (UIF/SWITCH/CASE/DEFAULT/ENDSWITCH).
1652 .. opcode:: CAL - Subroutine Call
1658 .. opcode:: RET - Subroutine Call Return
1663 .. opcode:: CONT - Continue
1665 Unconditionally moves the point of execution to the instruction after the
1666 last BGNLOOP. The instruction must appear within a BGNLOOP/ENDLOOP.
1670 Support for CONT is determined by a special capability bit,
1671 ``TGSI_CONT_SUPPORTED``. See :ref:`Screen` for more information.
1674 .. opcode:: BGNLOOP - Begin a Loop
1676 Start a loop. Must have a matching ENDLOOP.
1679 .. opcode:: BGNSUB - Begin Subroutine
1681 Starts definition of a subroutine. Must have a matching ENDSUB.
1684 .. opcode:: ENDLOOP - End a Loop
1686 End a loop started with BGNLOOP.
1689 .. opcode:: ENDSUB - End Subroutine
1691 Ends definition of a subroutine.
1694 .. opcode:: NOP - No Operation
1699 .. opcode:: BRK - Break
1701 Unconditionally moves the point of execution to the instruction after the
1702 next ENDLOOP or ENDSWITCH. The instruction must appear within a
1703 BGNLOOP/ENDLOOP or SWITCH/ENDSWITCH.
1706 .. opcode:: IF - Float If
1708 Start an IF ... ELSE .. ENDIF block. Condition evaluates to true if
1712 where *src0.x* is interpreted as a floating point register.
1715 .. opcode:: UIF - Bitwise If
1717 Start an UIF ... ELSE .. ENDIF block. Condition evaluates to true if
1721 where *src0.x* is interpreted as an integer register.
1724 .. opcode:: ELSE - Else
1726 Starts an else block, after an IF or UIF statement.
1729 .. opcode:: ENDIF - End If
1731 Ends an IF or UIF block.
1734 .. opcode:: SWITCH - Switch
1736 Starts a C-style switch expression. The switch consists of one or multiple
1737 CASE statements, and at most one DEFAULT statement. Execution of a statement
1738 ends when a BRK is hit, but just like in C falling through to other cases
1739 without a break is allowed. Similarly, DEFAULT label is allowed anywhere not
1740 just as last statement, and fallthrough is allowed into/from it.
1741 CASE *src* arguments are evaluated at bit level against the SWITCH *src* argument.
1747 (some instructions here)
1750 (some instructions here)
1753 (some instructions here)
1758 .. opcode:: CASE - Switch case
1760 This represents a switch case label. The *src* arg must be an integer immediate.
1763 .. opcode:: DEFAULT - Switch default
1765 This represents the default case in the switch, which is taken if no other
1769 .. opcode:: ENDSWITCH - End of switch
1771 Ends a switch expression.
1777 The interpolation instructions allow an input to be interpolated in a
1778 different way than its declaration. This corresponds to the GLSL 4.00
1779 interpolateAt* functions. The first argument of each of these must come from
1780 ``TGSI_FILE_INPUT``.
1782 .. opcode:: INTERP_CENTROID - Interpolate at the centroid
1784 Interpolates the varying specified by *src0* at the centroid
1786 .. opcode:: INTERP_SAMPLE - Interpolate at the specified sample
1788 Interpolates the varying specified by *src0* at the sample id
1789 specified by *src1.x* (interpreted as an integer)
1791 .. opcode:: INTERP_OFFSET - Interpolate at the specified offset
1793 Interpolates the varying specified by *src0* at the offset *src1.xy*
1794 from the pixel center (interpreted as floats)
1802 The double-precision opcodes reinterpret four-component vectors into
1803 two-component vectors with doubled precision in each component.
1805 .. opcode:: DABS - Absolute
1813 .. opcode:: DADD - Add
1817 dst.xy = src0.xy + src1.xy
1819 dst.zw = src0.zw + src1.zw
1821 .. opcode:: DSEQ - Set on Equal
1825 dst.x = src0.xy == src1.xy ? \sim 0 : 0
1827 dst.z = src0.zw == src1.zw ? \sim 0 : 0
1829 .. opcode:: DSNE - Set on Not Equal
1833 dst.x = src0.xy != src1.xy ? \sim 0 : 0
1835 dst.z = src0.zw != src1.zw ? \sim 0 : 0
1837 .. opcode:: DSLT - Set on Less than
1841 dst.x = src0.xy < src1.xy ? \sim 0 : 0
1843 dst.z = src0.zw < src1.zw ? \sim 0 : 0
1845 .. opcode:: DSGE - Set on Greater equal
1849 dst.x = src0.xy >= src1.xy ? \sim 0 : 0
1851 dst.z = src0.zw >= src1.zw ? \sim 0 : 0
1853 .. opcode:: DFRAC - Fraction
1857 dst.xy = src.xy - \lfloor src.xy\rfloor
1859 dst.zw = src.zw - \lfloor src.zw\rfloor
1861 .. opcode:: DTRUNC - Truncate
1865 dst.xy = trunc(src.xy)
1867 dst.zw = trunc(src.zw)
1869 .. opcode:: DCEIL - Ceiling
1873 dst.xy = \lceil src.xy\rceil
1875 dst.zw = \lceil src.zw\rceil
1877 .. opcode:: DFLR - Floor
1881 dst.xy = \lfloor src.xy\rfloor
1883 dst.zw = \lfloor src.zw\rfloor
1885 .. opcode:: DROUND - Fraction
1889 dst.xy = round(src.xy)
1891 dst.zw = round(src.zw)
1893 .. opcode:: DSSG - Set Sign
1897 dst.xy = (src.xy > 0) ? 1.0 : (src.xy < 0) ? -1.0 : 0.0
1899 dst.zw = (src.zw > 0) ? 1.0 : (src.zw < 0) ? -1.0 : 0.0
1901 .. opcode:: DFRACEXP - Convert Number to Fractional and Integral Components
1903 Like the ``frexp()`` routine in many math libraries, this opcode stores the
1904 exponent of its source to ``dst0``, and the significand to ``dst1``, such that
1905 :math:`dst1 \times 2^{dst0} = src` . The results are replicated across
1910 dst0.xy = dst.zw = frac(src.xy)
1915 .. opcode:: DLDEXP - Multiply Number by Integral Power of 2
1917 This opcode is the inverse of :opcode:`DFRACEXP`. The second
1918 source is an integer.
1922 dst.xy = src0.xy \times 2^{src1.x}
1924 dst.zw = src0.zw \times 2^{src1.z}
1926 .. opcode:: DMIN - Minimum
1930 dst.xy = min(src0.xy, src1.xy)
1932 dst.zw = min(src0.zw, src1.zw)
1934 .. opcode:: DMAX - Maximum
1938 dst.xy = max(src0.xy, src1.xy)
1940 dst.zw = max(src0.zw, src1.zw)
1942 .. opcode:: DMUL - Multiply
1946 dst.xy = src0.xy \times src1.xy
1948 dst.zw = src0.zw \times src1.zw
1951 .. opcode:: DMAD - Multiply And Add
1955 dst.xy = src0.xy \times src1.xy + src2.xy
1957 dst.zw = src0.zw \times src1.zw + src2.zw
1960 .. opcode:: DFMA - Fused Multiply-Add
1962 Perform a * b + c with no intermediate rounding step.
1966 dst.xy = src0.xy \times src1.xy + src2.xy
1968 dst.zw = src0.zw \times src1.zw + src2.zw
1971 .. opcode:: DDIV - Divide
1975 dst.xy = \frac{src0.xy}{src1.xy}
1977 dst.zw = \frac{src0.zw}{src1.zw}
1980 .. opcode:: DRCP - Reciprocal
1984 dst.xy = \frac{1}{src.xy}
1986 dst.zw = \frac{1}{src.zw}
1988 .. opcode:: DSQRT - Square Root
1992 dst.xy = \sqrt{src.xy}
1994 dst.zw = \sqrt{src.zw}
1996 .. opcode:: DRSQ - Reciprocal Square Root
2000 dst.xy = \frac{1}{\sqrt{src.xy}}
2002 dst.zw = \frac{1}{\sqrt{src.zw}}
2004 .. opcode:: F2D - Float to Double
2008 dst.xy = double(src0.x)
2010 dst.zw = double(src0.y)
2012 .. opcode:: D2F - Double to Float
2016 dst.x = float(src0.xy)
2018 dst.y = float(src0.zw)
2020 .. opcode:: I2D - Int to Double
2024 dst.xy = double(src0.x)
2026 dst.zw = double(src0.y)
2028 .. opcode:: D2I - Double to Int
2032 dst.x = int(src0.xy)
2034 dst.y = int(src0.zw)
2036 .. opcode:: U2D - Unsigned Int to Double
2040 dst.xy = double(src0.x)
2042 dst.zw = double(src0.y)
2044 .. opcode:: D2U - Double to Unsigned Int
2048 dst.x = unsigned(src0.xy)
2050 dst.y = unsigned(src0.zw)
2055 The 64-bit integer opcodes reinterpret four-component vectors into
2056 two-component vectors with 64-bits in each component.
2058 .. opcode:: I64ABS - 64-bit Integer Absolute Value
2066 .. opcode:: I64NEG - 64-bit Integer Negate
2076 .. opcode:: I64SSG - 64-bit Integer Set Sign
2080 dst.xy = (src0.xy < 0) ? -1 : (src0.xy > 0) ? 1 : 0
2082 dst.zw = (src0.zw < 0) ? -1 : (src0.zw > 0) ? 1 : 0
2084 .. opcode:: U64ADD - 64-bit Integer Add
2088 dst.xy = src0.xy + src1.xy
2090 dst.zw = src0.zw + src1.zw
2092 .. opcode:: U64MUL - 64-bit Integer Multiply
2096 dst.xy = src0.xy * src1.xy
2098 dst.zw = src0.zw * src1.zw
2100 .. opcode:: U64SEQ - 64-bit Integer Set on Equal
2104 dst.x = src0.xy == src1.xy ? \sim 0 : 0
2106 dst.z = src0.zw == src1.zw ? \sim 0 : 0
2108 .. opcode:: U64SNE - 64-bit Integer Set on Not Equal
2112 dst.x = src0.xy != src1.xy ? \sim 0 : 0
2114 dst.z = src0.zw != src1.zw ? \sim 0 : 0
2116 .. opcode:: U64SLT - 64-bit Unsigned Integer Set on Less Than
2120 dst.x = src0.xy < src1.xy ? \sim 0 : 0
2122 dst.z = src0.zw < src1.zw ? \sim 0 : 0
2124 .. opcode:: U64SGE - 64-bit Unsigned Integer Set on Greater Equal
2128 dst.x = src0.xy >= src1.xy ? \sim 0 : 0
2130 dst.z = src0.zw >= src1.zw ? \sim 0 : 0
2132 .. opcode:: I64SLT - 64-bit Signed Integer Set on Less Than
2136 dst.x = src0.xy < src1.xy ? \sim 0 : 0
2138 dst.z = src0.zw < src1.zw ? \sim 0 : 0
2140 .. opcode:: I64SGE - 64-bit Signed Integer Set on Greater Equal
2144 dst.x = src0.xy >= src1.xy ? \sim 0 : 0
2146 dst.z = src0.zw >= src1.zw ? \sim 0 : 0
2148 .. opcode:: I64MIN - Minimum of 64-bit Signed Integers
2152 dst.xy = min(src0.xy, src1.xy)
2154 dst.zw = min(src0.zw, src1.zw)
2156 .. opcode:: U64MIN - Minimum of 64-bit Unsigned Integers
2160 dst.xy = min(src0.xy, src1.xy)
2162 dst.zw = min(src0.zw, src1.zw)
2164 .. opcode:: I64MAX - Maximum of 64-bit Signed Integers
2168 dst.xy = max(src0.xy, src1.xy)
2170 dst.zw = max(src0.zw, src1.zw)
2172 .. opcode:: U64MAX - Maximum of 64-bit Unsigned Integers
2176 dst.xy = max(src0.xy, src1.xy)
2178 dst.zw = max(src0.zw, src1.zw)
2180 .. opcode:: U64SHL - Shift Left 64-bit Unsigned Integer
2182 The shift count is masked with 0x3f before the shift is applied.
2186 dst.xy = src0.xy << (0x3f \& src1.x)
2188 dst.zw = src0.zw << (0x3f \& src1.y)
2190 .. opcode:: I64SHR - Arithmetic Shift Right (of 64-bit Signed Integer)
2192 The shift count is masked with 0x3f before the shift is applied.
2196 dst.xy = src0.xy >> (0x3f \& src1.x)
2198 dst.zw = src0.zw >> (0x3f \& src1.y)
2200 .. opcode:: U64SHR - Logical Shift Right (of 64-bit Unsigned Integer)
2202 The shift count is masked with 0x3f before the shift is applied.
2206 dst.xy = src0.xy >> (unsigned) (0x3f \& src1.x)
2208 dst.zw = src0.zw >> (unsigned) (0x3f \& src1.y)
2210 .. opcode:: I64DIV - 64-bit Signed Integer Division
2214 dst.xy = \frac{src0.xy}{src1.xy}
2216 dst.zw = \frac{src0.zw}{src1.zw}
2218 .. opcode:: U64DIV - 64-bit Unsigned Integer Division
2222 dst.xy = \frac{src0.xy}{src1.xy}
2224 dst.zw = \frac{src0.zw}{src1.zw}
2226 .. opcode:: U64MOD - 64-bit Unsigned Integer Remainder
2230 dst.xy = src0.xy \bmod src1.xy
2232 dst.zw = src0.zw \bmod src1.zw
2234 .. opcode:: I64MOD - 64-bit Signed Integer Remainder
2238 dst.xy = src0.xy \bmod src1.xy
2240 dst.zw = src0.zw \bmod src1.zw
2242 .. opcode:: F2U64 - Float to 64-bit Unsigned Int
2246 dst.xy = (uint64_t) src0.x
2248 dst.zw = (uint64_t) src0.y
2250 .. opcode:: F2I64 - Float to 64-bit Int
2254 dst.xy = (int64_t) src0.x
2256 dst.zw = (int64_t) src0.y
2258 .. opcode:: U2I64 - Unsigned Integer to 64-bit Integer
2260 This is a zero extension.
2264 dst.xy = (int64_t) src0.x
2266 dst.zw = (int64_t) src0.y
2268 .. opcode:: I2I64 - Signed Integer to 64-bit Integer
2270 This is a sign extension.
2274 dst.xy = (int64_t) src0.x
2276 dst.zw = (int64_t) src0.y
2278 .. opcode:: D2U64 - Double to 64-bit Unsigned Int
2282 dst.xy = (uint64_t) src0.xy
2284 dst.zw = (uint64_t) src0.zw
2286 .. opcode:: D2I64 - Double to 64-bit Int
2290 dst.xy = (int64_t) src0.xy
2292 dst.zw = (int64_t) src0.zw
2294 .. opcode:: U642F - 64-bit unsigned integer to float
2298 dst.x = (float) src0.xy
2300 dst.y = (float) src0.zw
2302 .. opcode:: I642F - 64-bit Int to Float
2306 dst.x = (float) src0.xy
2308 dst.y = (float) src0.zw
2310 .. opcode:: U642D - 64-bit unsigned integer to double
2314 dst.xy = (double) src0.xy
2316 dst.zw = (double) src0.zw
2318 .. opcode:: I642D - 64-bit Int to double
2322 dst.xy = (double) src0.xy
2324 dst.zw = (double) src0.zw
2326 .. _samplingopcodes:
2328 Resource Sampling Opcodes
2329 ^^^^^^^^^^^^^^^^^^^^^^^^^
2331 Those opcodes follow very closely semantics of the respective Direct3D
2332 instructions. If in doubt double check Direct3D documentation.
2333 Note that the swizzle on SVIEW (src1) determines texel swizzling
2338 Using provided address, sample data from the specified texture using the
2339 filtering mode identified by the given sampler. The source data may come from
2340 any resource type other than buffers.
2342 Syntax: ``SAMPLE dst, address, sampler_view, sampler``
2344 Example: ``SAMPLE TEMP[0], TEMP[1], SVIEW[0], SAMP[0]``
2346 .. opcode:: SAMPLE_I
2348 Simplified alternative to the SAMPLE instruction. Using the provided
2349 integer address, SAMPLE_I fetches data from the specified sampler view
2350 without any filtering. The source data may come from any resource type
2353 Syntax: ``SAMPLE_I dst, address, sampler_view``
2355 Example: ``SAMPLE_I TEMP[0], TEMP[1], SVIEW[0]``
2357 The 'address' is specified as unsigned integers. If the 'address' is out of
2358 range [0...(# texels - 1)] the result of the fetch is always 0 in all
2359 components. As such the instruction doesn't honor address wrap modes, in
2360 cases where that behavior is desirable 'SAMPLE' instruction should be used.
2361 address.w always provides an unsigned integer mipmap level. If the value is
2362 out of the range then the instruction always returns 0 in all components.
2363 address.yz are ignored for buffers and 1d textures. address.z is ignored
2364 for 1d texture arrays and 2d textures.
2366 For 1D texture arrays address.y provides the array index (also as unsigned
2367 integer). If the value is out of the range of available array indices
2368 [0... (array size - 1)] then the opcode always returns 0 in all components.
2369 For 2D texture arrays address.z provides the array index, otherwise it
2370 exhibits the same behavior as in the case for 1D texture arrays. The exact
2371 semantics of the source address are presented in the table below:
2373 +---------------------------+----+-----+-----+---------+
2374 | resource type | X | Y | Z | W |
2375 +===========================+====+=====+=====+=========+
2376 | ``PIPE_BUFFER`` | x | | | ignored |
2377 +---------------------------+----+-----+-----+---------+
2378 | ``PIPE_TEXTURE_1D`` | x | | | mpl |
2379 +---------------------------+----+-----+-----+---------+
2380 | ``PIPE_TEXTURE_2D`` | x | y | | mpl |
2381 +---------------------------+----+-----+-----+---------+
2382 | ``PIPE_TEXTURE_3D`` | x | y | z | mpl |
2383 +---------------------------+----+-----+-----+---------+
2384 | ``PIPE_TEXTURE_RECT`` | x | y | | mpl |
2385 +---------------------------+----+-----+-----+---------+
2386 | ``PIPE_TEXTURE_CUBE`` | not allowed as source |
2387 +---------------------------+----+-----+-----+---------+
2388 | ``PIPE_TEXTURE_1D_ARRAY`` | x | idx | | mpl |
2389 +---------------------------+----+-----+-----+---------+
2390 | ``PIPE_TEXTURE_2D_ARRAY`` | x | y | idx | mpl |
2391 +---------------------------+----+-----+-----+---------+
2393 Where 'mpl' is a mipmap level and 'idx' is the array index.
2395 .. opcode:: SAMPLE_I_MS
2397 Just like SAMPLE_I but allows fetch data from multi-sampled surfaces.
2399 Syntax: ``SAMPLE_I_MS dst, address, sampler_view, sample``
2401 .. opcode:: SAMPLE_B
2403 Just like the SAMPLE instruction with the exception that an additional bias
2404 is applied to the level of detail computed as part of the instruction
2407 Syntax: ``SAMPLE_B dst, address, sampler_view, sampler, lod_bias``
2409 Example: ``SAMPLE_B TEMP[0], TEMP[1], SVIEW[0], SAMP[0], TEMP[2].x``
2411 .. opcode:: SAMPLE_C
2413 Similar to the SAMPLE instruction but it performs a comparison filter. The
2414 operands to SAMPLE_C are identical to SAMPLE, except that there is an
2415 additional float32 operand, reference value, which must be a register with
2416 single-component, or a scalar literal. SAMPLE_C makes the hardware use the
2417 current samplers compare_func (in pipe_sampler_state) to compare reference
2418 value against the red component value for the surce resource at each texel
2419 that the currently configured texture filter covers based on the provided
2422 Syntax: ``SAMPLE_C dst, address, sampler_view.r, sampler, ref_value``
2424 Example: ``SAMPLE_C TEMP[0], TEMP[1], SVIEW[0].r, SAMP[0], TEMP[2].x``
2426 .. opcode:: SAMPLE_C_LZ
2428 Same as SAMPLE_C, but LOD is 0 and derivatives are ignored. The LZ stands
2431 Syntax: ``SAMPLE_C_LZ dst, address, sampler_view.r, sampler, ref_value``
2433 Example: ``SAMPLE_C_LZ TEMP[0], TEMP[1], SVIEW[0].r, SAMP[0], TEMP[2].x``
2436 .. opcode:: SAMPLE_D
2438 SAMPLE_D is identical to the SAMPLE opcode except that the derivatives for
2439 the source address in the x direction and the y direction are provided by
2442 Syntax: ``SAMPLE_D dst, address, sampler_view, sampler, der_x, der_y``
2444 Example: ``SAMPLE_D TEMP[0], TEMP[1], SVIEW[0], SAMP[0], TEMP[2], TEMP[3]``
2446 .. opcode:: SAMPLE_L
2448 SAMPLE_L is identical to the SAMPLE opcode except that the LOD is provided
2449 directly as a scalar value, representing no anisotropy.
2451 Syntax: ``SAMPLE_L dst, address, sampler_view, sampler, explicit_lod``
2453 Example: ``SAMPLE_L TEMP[0], TEMP[1], SVIEW[0], SAMP[0], TEMP[2].x``
2457 Gathers the four texels to be used in a bi-linear filtering operation and
2458 packs them into a single register. Only works with 2D, 2D array, cubemaps,
2459 and cubemaps arrays. For 2D textures, only the addressing modes of the
2460 sampler and the top level of any mip pyramid are used. Set W to zero. It
2461 behaves like the SAMPLE instruction, but a filtered sample is not
2462 generated. The four samples that contribute to filtering are placed into
2463 XYZW in counter-clockwise order, starting with the (u,v) texture coordinate
2464 delta at the following locations (-, +), (+, +), (+, -), (-, -), where the
2465 magnitude of the deltas are half a texel.
2468 .. opcode:: SVIEWINFO
2470 Query the dimensions of a given sampler view. dst receives width, height,
2471 depth or array size and number of mipmap levels as int4. The dst can have a
2472 writemask which will specify what info is the caller interested in.
2474 Syntax: ``SVIEWINFO dst, src_mip_level, sampler_view``
2476 Example: ``SVIEWINFO TEMP[0], TEMP[1].x, SVIEW[0]``
2478 src_mip_level is an unsigned integer scalar. If it's out of range then
2479 returns 0 for width, height and depth/array size but the total number of
2480 mipmap is still returned correctly for the given sampler view. The returned
2481 width, height and depth values are for the mipmap level selected by the
2482 src_mip_level and are in the number of texels. For 1d texture array width
2483 is in dst.x, array size is in dst.y and dst.z is 0. The number of mipmaps is
2484 still in dst.w. In contrast to d3d10 resinfo, there's no way in the tgsi
2485 instruction encoding to specify the return type (float/rcpfloat/uint), hence
2486 always using uint. Also, unlike the SAMPLE instructions, the swizzle on src1
2487 resinfo allowing swizzling dst values is ignored (due to the interaction
2488 with rcpfloat modifier which requires some swizzle handling in the state
2491 .. opcode:: SAMPLE_POS
2493 Query the position of a sample in the given resource or render target
2494 when per-sample fragment shading is in effect.
2496 Syntax: ``SAMPLE_POS dst, source, sample_index``
2498 dst receives float4 (x, y, undef, undef) indicated where the sample is
2499 located. Sample locations are in the range [0, 1] where 0.5 is the center
2502 source is either a sampler view (to indicate a shader resource) or temp
2503 register (to indicate the render target). The source register may have
2504 an optional swizzle to apply to the returned result
2506 sample_index is an integer scalar indicating which sample position is to
2509 If per-sample shading is not in effect or the source resource or render
2510 target is not multisampled, the result is (0.5, 0.5, undef, undef).
2512 NOTE: no driver has implemented this opcode yet (and no gallium frontend
2513 emits it). This information is subject to change.
2515 .. opcode:: SAMPLE_INFO
2517 Query the number of samples in a multisampled resource or render target.
2519 Syntax: ``SAMPLE_INFO dst, source``
2521 dst receives int4 (n, 0, 0, 0) where n is the number of samples in a
2522 resource or the render target.
2524 source is either a sampler view (to indicate a shader resource) or temp
2525 register (to indicate the render target). The source register may have
2526 an optional swizzle to apply to the returned result
2528 If per-sample shading is not in effect or the source resource or render
2529 target is not multisampled, the result is (1, 0, 0, 0).
2531 NOTE: no driver has implemented this opcode yet (and no gallium frontend
2532 emits it). This information is subject to change.
2534 .. opcode:: LOD - level of detail
2536 Same syntax as the SAMPLE opcode but instead of performing an actual
2537 texture lookup/filter, return the computed LOD information that the
2538 texture pipe would use to access the texture. The Y component contains
2539 the computed LOD lambda_prime. The X component contains the LOD that will
2540 be accessed, based on min/max lod's and mipmap filters.
2541 The Z and W components are set to 0.
2543 Syntax: ``LOD dst, address, sampler_view, sampler``
2546 .. _resourceopcodes:
2548 Resource Access Opcodes
2549 ^^^^^^^^^^^^^^^^^^^^^^^
2551 For these opcodes, the resource can be a BUFFER, IMAGE, or MEMORY.
2553 .. opcode:: LOAD - Fetch data from a shader buffer or image
2555 Syntax: ``LOAD dst, resource, address``
2557 Example: ``LOAD TEMP[0], BUFFER[0], TEMP[1]``
2559 Using the provided integer address, LOAD fetches data
2560 from the specified buffer or texture without any
2563 The 'address' is specified as a vector of unsigned
2564 integers. If the 'address' is out of range the result
2567 Only the first mipmap level of a resource can be read
2568 from using this instruction.
2570 For 1D or 2D texture arrays, the array index is
2571 provided as an unsigned integer in address.y or
2572 address.z, respectively. address.yz are ignored for
2573 buffers and 1D textures. address.z is ignored for 1D
2574 texture arrays and 2D textures. address.w is always
2577 A swizzle suffix may be added to the resource argument
2578 this will cause the resource data to be swizzled accordingly.
2580 .. opcode:: STORE - Write data to a shader resource
2582 Syntax: ``STORE resource, address, src``
2584 Example: ``STORE BUFFER[0], TEMP[0], TEMP[1]``
2586 Using the provided integer address, STORE writes data
2587 to the specified buffer or texture.
2589 The 'address' is specified as a vector of unsigned
2590 integers. If the 'address' is out of range the result
2593 Only the first mipmap level of a resource can be
2594 written to using this instruction.
2596 For 1D or 2D texture arrays, the array index is
2597 provided as an unsigned integer in address.y or
2598 address.z, respectively. address.yz are ignored for
2599 buffers and 1D textures. address.z is ignored for 1D
2600 texture arrays and 2D textures. address.w is always
2603 .. opcode:: RESQ - Query information about a resource
2605 Syntax: ``RESQ dst, resource``
2607 Example: ``RESQ TEMP[0], BUFFER[0]``
2609 Returns information about the buffer or image resource. For buffer
2610 resources, the size (in bytes) is returned in the x component. For
2611 image resources, .xyz will contain the width/height/layers of the
2612 image, while .w will contain the number of samples for multi-sampled
2615 .. opcode:: FBFETCH - Load data from framebuffer
2617 Syntax: ``FBFETCH dst, output``
2619 Example: ``FBFETCH TEMP[0], OUT[0]``
2621 This is only valid on ``COLOR`` semantic outputs. Returns the color
2622 of the current position in the framebuffer from before this fragment
2623 shader invocation. May return the same value from multiple calls for
2624 a particular output within a single invocation. Note that result may
2625 be undefined if a fragment is drawn multiple times without a blend
2629 .. _bindlessopcodes:
2634 These opcodes are for working with bindless sampler or image handles and
2635 require PIPE_CAP_BINDLESS_TEXTURE.
2637 .. opcode:: IMG2HND - Get a bindless handle for a image
2639 Syntax: ``IMG2HND dst, image``
2641 Example: ``IMG2HND TEMP[0], IMAGE[0]``
2643 Sets 'dst' to a bindless handle for 'image'.
2645 .. opcode:: SAMP2HND - Get a bindless handle for a sampler
2647 Syntax: ``SAMP2HND dst, sampler``
2649 Example: ``SAMP2HND TEMP[0], SAMP[0]``
2651 Sets 'dst' to a bindless handle for 'sampler'.
2654 .. _threadsyncopcodes:
2656 Inter-thread synchronization opcodes
2657 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2659 These opcodes are intended for communication between threads running
2660 within the same compute grid. For now they're only valid in compute
2663 .. opcode:: BARRIER - Thread group barrier
2667 This opcode suspends the execution of the current thread until all
2668 the remaining threads in the working group reach the same point of
2669 the program. Results are unspecified if any of the remaining
2670 threads terminates or never reaches an executed BARRIER instruction.
2672 .. opcode:: MEMBAR - Memory barrier
2676 This opcode waits for the completion of all memory accesses based on
2677 the type passed in. The type is an immediate bitfield with the following
2680 Bit 0: Shader storage buffers
2681 Bit 1: Atomic buffers
2683 Bit 3: Shared memory
2686 These may be passed in in any combination. An implementation is free to not
2687 distinguish between these as it sees fit. However these map to all the
2688 possibilities made available by GLSL.
2695 These opcodes provide atomic variants of some common arithmetic and
2696 logical operations. In this context atomicity means that another
2697 concurrent memory access operation that affects the same memory
2698 location is guaranteed to be performed strictly before or after the
2699 entire execution of the atomic operation. The resource may be a BUFFER,
2700 IMAGE, HWATOMIC, or MEMORY. In the case of an image, the offset works
2701 the same as for ``LOAD`` and ``STORE``, specified above. For atomic
2702 counters, the offset is an immediate index to the base HW atomic
2703 counter for this operation.
2704 These atomic operations may only be used with 32-bit integer image formats.
2706 .. opcode:: ATOMUADD - Atomic integer addition
2708 Syntax: ``ATOMUADD dst, resource, offset, src``
2710 Example: ``ATOMUADD TEMP[0], BUFFER[0], TEMP[1], TEMP[2]``
2712 The following operation is performed atomically:
2716 dst_x = resource[offset]
2718 resource[offset] = dst_x + src_x
2721 .. opcode:: ATOMFADD - Atomic floating point addition
2723 Syntax: ``ATOMFADD dst, resource, offset, src``
2725 Example: ``ATOMFADD TEMP[0], BUFFER[0], TEMP[1], TEMP[2]``
2727 The following operation is performed atomically:
2731 dst_x = resource[offset]
2733 resource[offset] = dst_x + src_x
2736 .. opcode:: ATOMXCHG - Atomic exchange
2738 Syntax: ``ATOMXCHG dst, resource, offset, src``
2740 Example: ``ATOMXCHG TEMP[0], BUFFER[0], TEMP[1], TEMP[2]``
2742 The following operation is performed atomically:
2746 dst_x = resource[offset]
2748 resource[offset] = src_x
2751 .. opcode:: ATOMCAS - Atomic compare-and-exchange
2753 Syntax: ``ATOMCAS dst, resource, offset, cmp, src``
2755 Example: ``ATOMCAS TEMP[0], BUFFER[0], TEMP[1], TEMP[2], TEMP[3]``
2757 The following operation is performed atomically:
2761 dst_x = resource[offset]
2763 resource[offset] = (dst_x == cmp_x ? src_x : dst_x)
2766 .. opcode:: ATOMAND - Atomic bitwise And
2768 Syntax: ``ATOMAND dst, resource, offset, src``
2770 Example: ``ATOMAND TEMP[0], BUFFER[0], TEMP[1], TEMP[2]``
2772 The following operation is performed atomically:
2776 dst_x = resource[offset]
2778 resource[offset] = dst_x \& src_x
2781 .. opcode:: ATOMOR - Atomic bitwise Or
2783 Syntax: ``ATOMOR dst, resource, offset, src``
2785 Example: ``ATOMOR TEMP[0], BUFFER[0], TEMP[1], TEMP[2]``
2787 The following operation is performed atomically:
2791 dst_x = resource[offset]
2793 resource[offset] = dst_x | src_x
2796 .. opcode:: ATOMXOR - Atomic bitwise Xor
2798 Syntax: ``ATOMXOR dst, resource, offset, src``
2800 Example: ``ATOMXOR TEMP[0], BUFFER[0], TEMP[1], TEMP[2]``
2802 The following operation is performed atomically:
2806 dst_x = resource[offset]
2808 resource[offset] = dst_x \oplus src_x
2811 .. opcode:: ATOMUMIN - Atomic unsigned minimum
2813 Syntax: ``ATOMUMIN dst, resource, offset, src``
2815 Example: ``ATOMUMIN TEMP[0], BUFFER[0], TEMP[1], TEMP[2]``
2817 The following operation is performed atomically:
2821 dst_x = resource[offset]
2823 resource[offset] = (dst_x < src_x ? dst_x : src_x)
2826 .. opcode:: ATOMUMAX - Atomic unsigned maximum
2828 Syntax: ``ATOMUMAX dst, resource, offset, src``
2830 Example: ``ATOMUMAX TEMP[0], BUFFER[0], TEMP[1], TEMP[2]``
2832 The following operation is performed atomically:
2836 dst_x = resource[offset]
2838 resource[offset] = (dst_x > src_x ? dst_x : src_x)
2841 .. opcode:: ATOMIMIN - Atomic signed minimum
2843 Syntax: ``ATOMIMIN dst, resource, offset, src``
2845 Example: ``ATOMIMIN TEMP[0], BUFFER[0], TEMP[1], TEMP[2]``
2847 The following operation is performed atomically:
2851 dst_x = resource[offset]
2853 resource[offset] = (dst_x < src_x ? dst_x : src_x)
2856 .. opcode:: ATOMIMAX - Atomic signed maximum
2858 Syntax: ``ATOMIMAX dst, resource, offset, src``
2860 Example: ``ATOMIMAX TEMP[0], BUFFER[0], TEMP[1], TEMP[2]``
2862 The following operation is performed atomically:
2866 dst_x = resource[offset]
2868 resource[offset] = (dst_x > src_x ? dst_x : src_x)
2871 .. opcode:: ATOMINC_WRAP - Atomic increment + wrap around
2873 Syntax: ``ATOMINC_WRAP dst, resource, offset, src``
2875 Example: ``ATOMINC_WRAP TEMP[0], BUFFER[0], TEMP[1], TEMP[2]``
2877 The following operation is performed atomically:
2881 dst_x = resource[offset] + 1
2883 resource[offset] = dst_x <= src_x ? dst_x : 0
2886 .. opcode:: ATOMDEC_WRAP - Atomic decrement + wrap around
2888 Syntax: ``ATOMDEC_WRAP dst, resource, offset, src``
2890 Example: ``ATOMDEC_WRAP TEMP[0], BUFFER[0], TEMP[1], TEMP[2]``
2892 The following operation is performed atomically:
2896 dst_x = resource[offset]
2898 resource[offset] = (dst_x > 0 && dst_x < src_x) ? dst_x - 1 : 0
2901 .. _interlaneopcodes:
2906 These opcodes reduce the given value across the shader invocations
2907 running in the current SIMD group. Every thread in the subgroup will receive
2908 the same result. The BALLOT operations accept a single-channel argument that
2909 is treated as a boolean and produce a 64-bit value.
2911 .. opcode:: VOTE_ANY - Value is set in any of the active invocations
2913 Syntax: ``VOTE_ANY dst, value``
2915 Example: ``VOTE_ANY TEMP[0].x, TEMP[1].x``
2918 .. opcode:: VOTE_ALL - Value is set in all of the active invocations
2920 Syntax: ``VOTE_ALL dst, value``
2922 Example: ``VOTE_ALL TEMP[0].x, TEMP[1].x``
2925 .. opcode:: VOTE_EQ - Value is the same in all of the active invocations
2927 Syntax: ``VOTE_EQ dst, value``
2929 Example: ``VOTE_EQ TEMP[0].x, TEMP[1].x``
2932 .. opcode:: BALLOT - Lanemask of whether the value is set in each active
2935 Syntax: ``BALLOT dst, value``
2937 Example: ``BALLOT TEMP[0].xy, TEMP[1].x``
2939 When the argument is a constant true, this produces a bitmask of active
2940 invocations. In fragment shaders, this can include helper invocations
2941 (invocations whose outputs and writes to memory are discarded, but which
2942 are used to compute derivatives).
2945 .. opcode:: READ_FIRST - Broadcast the value from the first active
2946 invocation to all active lanes
2948 Syntax: ``READ_FIRST dst, value``
2950 Example: ``READ_FIRST TEMP[0], TEMP[1]``
2953 .. opcode:: READ_INVOC - Retrieve the value from the given invocation
2954 (need not be uniform)
2956 Syntax: ``READ_INVOC dst, value, invocation``
2958 Example: ``READ_INVOC TEMP[0].xy, TEMP[1].xy, TEMP[2].x``
2960 invocation.x controls the invocation number to read from for all channels.
2961 The invocation number must be the same across all active invocations in a
2962 sub-group; otherwise, the results are undefined.
2965 Explanation of symbols used
2966 ------------------------------
2973 :math:`|x|` Absolute value of `x`.
2975 :math:`\lceil x \rceil` Ceiling of `x`.
2977 clamp(x,y,z) Clamp x between y and z.
2978 (x < y) ? y : (x > z) ? z : x
2980 :math:`\lfloor x\rfloor` Floor of `x`.
2982 :math:`\log_2{x}` Logarithm of `x`, base 2.
2984 max(x,y) Maximum of x and y.
2987 min(x,y) Minimum of x and y.
2990 partialx(x) Derivative of x relative to fragment's X.
2992 partialy(x) Derivative of x relative to fragment's Y.
2994 pop() Pop from stack.
2996 :math:`x^y` `x` to the power `y`.
2998 push(x) Push x on stack.
3002 trunc(x) Truncate x, i.e. drop the fraction bits.
3009 discard Discard fragment.
3013 target Label of target instruction.
3024 Declares a register that is will be referenced as an operand in Instruction
3027 File field contains register file that is being declared and is one
3030 UsageMask field specifies which of the register components can be accessed
3031 and is one of TGSI_WRITEMASK.
3033 The Local flag specifies that a given value isn't intended for
3034 subroutine parameter passing and, as a result, the implementation
3035 isn't required to give any guarantees of it being preserved across
3036 subroutine boundaries. As it's merely a compiler hint, the
3037 implementation is free to ignore it.
3039 If Dimension flag is set to 1, a Declaration Dimension token follows.
3041 If Semantic flag is set to 1, a Declaration Semantic token follows.
3043 If Interpolate flag is set to 1, a Declaration Interpolate token follows.
3045 If file is TGSI_FILE_RESOURCE, a Declaration Resource token follows.
3047 If Array flag is set to 1, a Declaration Array token follows.
3050 ^^^^^^^^^^^^^^^^^^^^^^^^
3052 Declarations can optional have an ArrayID attribute which can be referred by
3053 indirect addressing operands. An ArrayID of zero is reserved and treated as
3054 if no ArrayID is specified.
3056 If an indirect addressing operand refers to a specific declaration by using
3057 an ArrayID only the registers in this declaration are guaranteed to be
3058 accessed, accessing any register outside this declaration results in undefined
3059 behavior. Note that for compatibility the effective index is zero-based and
3060 not relative to the specified declaration
3062 If no ArrayID is specified with an indirect addressing operand the whole
3063 register file might be accessed by this operand. This is strongly discouraged
3064 and will prevent packing of scalar/vec2 arrays and effective alias analysis.
3065 This is only legal for TEMP and CONST register files.
3067 Declaration Semantic
3068 ^^^^^^^^^^^^^^^^^^^^^^^^
3070 Vertex and fragment shader input and output registers may be labeled
3071 with semantic information consisting of a name and index.
3073 Follows Declaration token if Semantic bit is set.
3075 Since its purpose is to link a shader with other stages of the pipeline,
3076 it is valid to follow only those Declaration tokens that declare a register
3077 either in INPUT or OUTPUT file.
3079 SemanticName field contains the semantic name of the register being declared.
3080 There is no default value.
3082 SemanticIndex is an optional subscript that can be used to distinguish
3083 different register declarations with the same semantic name. The default value
3086 The meanings of the individual semantic names are explained in the following
3089 TGSI_SEMANTIC_POSITION
3090 """"""""""""""""""""""
3092 For vertex shaders, TGSI_SEMANTIC_POSITION indicates the vertex shader
3093 output register which contains the homogeneous vertex position in the clip
3094 space coordinate system. After clipping, the X, Y and Z components of the
3095 vertex will be divided by the W value to get normalized device coordinates.
3097 For fragment shaders, TGSI_SEMANTIC_POSITION is used to indicate that
3098 fragment shader input (or system value, depending on which one is
3099 supported by the driver) contains the fragment's window position. The X
3100 component starts at zero and always increases from left to right.
3101 The Y component starts at zero and always increases but Y=0 may either
3102 indicate the top of the window or the bottom depending on the fragment
3103 coordinate origin convention (see TGSI_PROPERTY_FS_COORD_ORIGIN).
3104 The Z coordinate ranges from 0 to 1 to represent depth from the front
3105 to the back of the Z buffer. The W component contains the interpolated
3106 reciprocal of the vertex position W component (corresponding to gl_Fragcoord,
3107 but unlike d3d10 which interpolates the same 1/w but then gives back
3108 the reciprocal of the interpolated value).
3110 Fragment shaders may also declare an output register with
3111 TGSI_SEMANTIC_POSITION. Only the Z component is writable. This allows
3112 the fragment shader to change the fragment's Z position.
3119 For vertex shader outputs or fragment shader inputs/outputs, this
3120 label indicates that the register contains an R,G,B,A color.
3122 Several shader inputs/outputs may contain colors so the semantic index
3123 is used to distinguish them. For example, color[0] may be the diffuse
3124 color while color[1] may be the specular color.
3126 This label is needed so that the flat/smooth shading can be applied
3127 to the right interpolants during rasterization.
3131 TGSI_SEMANTIC_BCOLOR
3132 """"""""""""""""""""
3134 Back-facing colors are only used for back-facing polygons, and are only valid
3135 in vertex shader outputs. After rasterization, all polygons are front-facing
3136 and COLOR and BCOLOR end up occupying the same slots in the fragment shader,
3137 so all BCOLORs effectively become regular COLORs in the fragment shader.
3143 Vertex shader inputs and outputs and fragment shader inputs may be
3144 labeled with TGSI_SEMANTIC_FOG to indicate that the register contains
3145 a fog coordinate. Typically, the fragment shader will use the fog coordinate
3146 to compute a fog blend factor which is used to blend the normal fragment color
3147 with a constant fog color. But fog coord really is just an ordinary vec4
3148 register like regular semantics.
3154 Vertex shader input and output registers may be labeled with
3155 TGIS_SEMANTIC_PSIZE to indicate that the register contains a point size
3156 in the form (S, 0, 0, 1). The point size controls the width or diameter
3157 of points for rasterization. This label cannot be used in fragment
3160 When using this semantic, be sure to set the appropriate state in the
3161 :ref:`rasterizer` first.
3164 TGSI_SEMANTIC_TEXCOORD
3165 """"""""""""""""""""""
3167 Only available if PIPE_CAP_TGSI_TEXCOORD is exposed !
3169 Vertex shader outputs and fragment shader inputs may be labeled with
3170 this semantic to make them replaceable by sprite coordinates via the
3171 sprite_coord_enable state in the :ref:`rasterizer`.
3172 The semantic index permitted with this semantic is limited to <= 7.
3174 If the driver does not support TEXCOORD, sprite coordinate replacement
3175 applies to inputs with the GENERIC semantic instead.
3177 The intended use case for this semantic is gl_TexCoord.
3180 TGSI_SEMANTIC_PCOORD
3181 """"""""""""""""""""
3183 Only available if PIPE_CAP_TGSI_TEXCOORD is exposed !
3185 Fragment shader inputs may be labeled with TGSI_SEMANTIC_PCOORD to indicate
3186 that the register contains sprite coordinates in the form (x, y, 0, 1), if
3187 the current primitive is a point and point sprites are enabled. Otherwise,
3188 the contents of the register are undefined.
3190 The intended use case for this semantic is gl_PointCoord.
3193 TGSI_SEMANTIC_GENERIC
3194 """""""""""""""""""""
3196 All vertex/fragment shader inputs/outputs not labeled with any other
3197 semantic label can be considered to be generic attributes. Typical
3198 uses of generic inputs/outputs are texcoords and user-defined values.
3201 TGSI_SEMANTIC_NORMAL
3202 """"""""""""""""""""
3204 Indicates that a vertex shader input is a normal vector. This is
3205 typically only used for legacy graphics APIs.
3211 This label applies to fragment shader inputs (or system values,
3212 depending on which one is supported by the driver) and indicates that
3213 the register contains front/back-face information.
3215 If it is an input, it will be a floating-point vector in the form (F, 0, 0, 1),
3216 where F will be positive when the fragment belongs to a front-facing polygon,
3217 and negative when the fragment belongs to a back-facing polygon.
3219 If it is a system value, it will be an integer vector in the form (F, 0, 0, 1),
3220 where F is 0xffffffff when the fragment belongs to a front-facing polygon and
3221 0 when the fragment belongs to a back-facing polygon.
3224 TGSI_SEMANTIC_EDGEFLAG
3225 """"""""""""""""""""""
3227 For vertex shaders, this semantic label indicates that an input or
3228 output is a boolean edge flag. The register layout is [F, x, x, x]
3229 where F is 0.0 or 1.0 and x = don't care. Normally, the vertex shader
3230 simply copies the edge flag input to the edgeflag output.
3232 Edge flags are used to control which lines or points are actually
3233 drawn when the polygon mode converts triangles/quads/polygons into
3237 TGSI_SEMANTIC_STENCIL
3238 """""""""""""""""""""
3240 For fragment shaders, this semantic label indicates that an output
3241 is a writable stencil reference value. Only the Y component is writable.
3242 This allows the fragment shader to change the fragments stencilref value.
3245 TGSI_SEMANTIC_VIEWPORT_INDEX
3246 """"""""""""""""""""""""""""
3248 For geometry shaders, this semantic label indicates that an output
3249 contains the index of the viewport (and scissor) to use.
3250 This is an integer value, and only the X component is used.
3252 If PIPE_CAP_VS_LAYER_VIEWPORT or PIPE_CAP_TES_LAYER_VIEWPORT is
3253 supported, then this semantic label can also be used in vertex or
3254 tessellation evaluation shaders, respectively. Only the value written in the
3255 last vertex processing stage is used.
3261 For geometry shaders, this semantic label indicates that an output
3262 contains the layer value to use for the color and depth/stencil surfaces.
3263 This is an integer value, and only the X component is used.
3264 (Also known as rendertarget array index.)
3266 If PIPE_CAP_VS_LAYER_VIEWPORT or PIPE_CAP_TES_LAYER_VIEWPORT is
3267 supported, then this semantic label can also be used in vertex or
3268 tessellation evaluation shaders, respectively. Only the value written in the
3269 last vertex processing stage is used.
3272 TGSI_SEMANTIC_CLIPDIST
3273 """"""""""""""""""""""
3275 Note this covers clipping and culling distances.
3277 When components of vertex elements are identified this way, these
3278 values are each assumed to be a float32 signed distance to a plane.
3281 Primitive setup only invokes rasterization on pixels for which
3282 the interpolated plane distances are >= 0.
3285 Primitives will be completely discarded if the plane distance
3286 for all of the vertices in the primitive are < 0.
3287 If a vertex has a cull distance of NaN, that vertex counts as "out"
3290 Multiple clip/cull planes can be implemented simultaneously, by
3291 annotating multiple components of one or more vertex elements with
3292 the above specified semantic.
3293 The limits on both clip and cull distances are bound
3294 by the PIPE_MAX_CLIP_OR_CULL_DISTANCE_COUNT define which defines
3295 the maximum number of components that can be used to hold the
3296 distances and by the PIPE_MAX_CLIP_OR_CULL_DISTANCE_ELEMENT_COUNT
3297 which specifies the maximum number of registers which can be
3298 annotated with those semantics.
3299 The properties NUM_CLIPDIST_ENABLED and NUM_CULLDIST_ENABLED
3300 are used to divide up the 2 x vec4 space between clipping and culling.
3302 TGSI_SEMANTIC_SAMPLEID
3303 """"""""""""""""""""""
3305 For fragment shaders, this semantic label indicates that a system value
3306 contains the current sample id (i.e. gl_SampleID) as an unsigned int.
3307 Only the X component is used. If per-sample shading is not enabled,
3308 the result is (0, undef, undef, undef).
3310 Note that if the fragment shader uses this system value, the fragment
3311 shader is automatically executed at per sample frequency.
3313 TGSI_SEMANTIC_SAMPLEPOS
3314 """""""""""""""""""""""
3316 For fragment shaders, this semantic label indicates that a system
3317 value contains the current sample's position as float4(x, y, undef, undef)
3318 in the render target (i.e. gl_SamplePosition) when per-fragment shading
3319 is in effect. Position values are in the range [0, 1] where 0.5 is
3320 the center of the fragment.
3322 Note that if the fragment shader uses this system value, the fragment
3323 shader is automatically executed at per sample frequency.
3325 TGSI_SEMANTIC_SAMPLEMASK
3326 """"""""""""""""""""""""
3328 For fragment shaders, this semantic label can be applied to either a
3329 shader system value input or output.
3331 For a system value, the sample mask indicates the set of samples covered by
3332 the current primitive. If MSAA is not enabled, the value is (1, 0, 0, 0).
3334 For an output, the sample mask is used to disable further sample processing.
3336 For both, the register type is uint[4] but only the X component is used
3337 (i.e. gl_SampleMask[0]). Each bit corresponds to one sample position (up
3338 to 32x MSAA is supported).
3340 TGSI_SEMANTIC_INVOCATIONID
3341 """"""""""""""""""""""""""
3343 For geometry shaders, this semantic label indicates that a system value
3344 contains the current invocation id (i.e. gl_InvocationID).
3345 This is an integer value, and only the X component is used.
3347 TGSI_SEMANTIC_INSTANCEID
3348 """"""""""""""""""""""""
3350 For vertex shaders, this semantic label indicates that a system value contains
3351 the current instance id (i.e. gl_InstanceID). It does not include the base
3352 instance. This is an integer value, and only the X component is used.
3354 TGSI_SEMANTIC_VERTEXID
3355 """"""""""""""""""""""
3357 For vertex shaders, this semantic label indicates that a system value contains
3358 the current vertex id (i.e. gl_VertexID). It does (unlike in d3d10) include the
3359 base vertex. This is an integer value, and only the X component is used.
3361 TGSI_SEMANTIC_VERTEXID_NOBASE
3362 """""""""""""""""""""""""""""""
3364 For vertex shaders, this semantic label indicates that a system value contains
3365 the current vertex id without including the base vertex (this corresponds to
3366 d3d10 vertex id, so TGSI_SEMANTIC_VERTEXID_NOBASE + TGSI_SEMANTIC_BASEVERTEX
3367 == TGSI_SEMANTIC_VERTEXID). This is an integer value, and only the X component
3370 TGSI_SEMANTIC_BASEVERTEX
3371 """"""""""""""""""""""""
3373 For vertex shaders, this semantic label indicates that a system value contains
3374 the base vertex (i.e. gl_BaseVertex). Note that for non-indexed draw calls,
3375 this contains the first (or start) value instead.
3376 This is an integer value, and only the X component is used.
3378 TGSI_SEMANTIC_PRIMID
3379 """"""""""""""""""""
3381 For geometry and fragment shaders, this semantic label indicates the value
3382 contains the primitive id (i.e. gl_PrimitiveID). This is an integer value,
3383 and only the X component is used.
3384 FIXME: This right now can be either a ordinary input or a system value...
3390 For tessellation evaluation/control shaders, this semantic label indicates a
3391 generic per-patch attribute. Such semantics will not implicitly be per-vertex
3394 TGSI_SEMANTIC_TESSCOORD
3395 """""""""""""""""""""""
3397 For tessellation evaluation shaders, this semantic label indicates the
3398 coordinates of the vertex being processed. This is available in XYZ; W is
3401 TGSI_SEMANTIC_TESSOUTER
3402 """""""""""""""""""""""
3404 For tessellation evaluation/control shaders, this semantic label indicates the
3405 outer tessellation levels of the patch. Isoline tessellation will only have XY
3406 defined, triangle will have XYZ and quads will have XYZW defined. This
3407 corresponds to gl_TessLevelOuter.
3409 TGSI_SEMANTIC_TESSINNER
3410 """""""""""""""""""""""
3412 For tessellation evaluation/control shaders, this semantic label indicates the
3413 inner tessellation levels of the patch. The X value is only defined for
3414 triangle tessellation, while quads will have XY defined. This is entirely
3415 undefined for isoline tessellation.
3417 TGSI_SEMANTIC_VERTICESIN
3418 """"""""""""""""""""""""
3420 For tessellation evaluation/control shaders, this semantic label indicates the
3421 number of vertices provided in the input patch. Only the X value is defined.
3423 TGSI_SEMANTIC_HELPER_INVOCATION
3424 """""""""""""""""""""""""""""""
3426 For fragment shaders, this semantic indicates whether the current
3427 invocation is covered or not. Helper invocations are created in order
3428 to properly compute derivatives, however it may be desirable to skip
3429 some of the logic in those cases. See ``gl_HelperInvocation`` documentation.
3431 TGSI_SEMANTIC_BASEINSTANCE
3432 """"""""""""""""""""""""""
3434 For vertex shaders, the base instance argument supplied for this
3435 draw. This is an integer value, and only the X component is used.
3437 TGSI_SEMANTIC_DRAWID
3438 """"""""""""""""""""
3440 For vertex shaders, the zero-based index of the current draw in a
3441 ``glMultiDraw*`` invocation. This is an integer value, and only the X
3445 TGSI_SEMANTIC_WORK_DIM
3446 """"""""""""""""""""""
3448 For compute shaders started via OpenCL this retrieves the work_dim
3449 parameter to the clEnqueueNDRangeKernel call with which the shader
3453 TGSI_SEMANTIC_GRID_SIZE
3454 """""""""""""""""""""""
3456 For compute shaders, this semantic indicates the maximum (x, y, z) dimensions
3457 of a grid of thread blocks.
3460 TGSI_SEMANTIC_BLOCK_ID
3461 """"""""""""""""""""""
3463 For compute shaders, this semantic indicates the (x, y, z) coordinates of the
3464 current block inside of the grid.
3467 TGSI_SEMANTIC_BLOCK_SIZE
3468 """"""""""""""""""""""""
3470 For compute shaders, this semantic indicates the maximum (x, y, z) dimensions
3471 of a block in threads.
3474 TGSI_SEMANTIC_THREAD_ID
3475 """""""""""""""""""""""
3477 For compute shaders, this semantic indicates the (x, y, z) coordinates of the
3478 current thread inside of the block.
3481 TGSI_SEMANTIC_SUBGROUP_SIZE
3482 """""""""""""""""""""""""""
3484 This semantic indicates the subgroup size for the current invocation. This is
3485 an integer of at most 64, as it indicates the width of lanemasks. It does not
3486 depend on the number of invocations that are active.
3489 TGSI_SEMANTIC_SUBGROUP_INVOCATION
3490 """""""""""""""""""""""""""""""""
3492 The index of the current invocation within its subgroup.
3495 TGSI_SEMANTIC_SUBGROUP_EQ_MASK
3496 """"""""""""""""""""""""""""""
3498 A bit mask of ``bit index == TGSI_SEMANTIC_SUBGROUP_INVOCATION``, i.e.
3499 ``1 << subgroup_invocation`` in arbitrary precision arithmetic.
3502 TGSI_SEMANTIC_SUBGROUP_GE_MASK
3503 """"""""""""""""""""""""""""""
3505 A bit mask of ``bit index >= TGSI_SEMANTIC_SUBGROUP_INVOCATION``, i.e.
3506 ``((1 << (subgroup_size - subgroup_invocation)) - 1) << subgroup_invocation``
3507 in arbitrary precision arithmetic.
3510 TGSI_SEMANTIC_SUBGROUP_GT_MASK
3511 """"""""""""""""""""""""""""""
3513 A bit mask of ``bit index > TGSI_SEMANTIC_SUBGROUP_INVOCATION``, i.e.
3514 ``((1 << (subgroup_size - subgroup_invocation - 1)) - 1) << (subgroup_invocation + 1)``
3515 in arbitrary precision arithmetic.
3518 TGSI_SEMANTIC_SUBGROUP_LE_MASK
3519 """"""""""""""""""""""""""""""
3521 A bit mask of ``bit index <= TGSI_SEMANTIC_SUBGROUP_INVOCATION``, i.e.
3522 ``(1 << (subgroup_invocation + 1)) - 1`` in arbitrary precision arithmetic.
3525 TGSI_SEMANTIC_SUBGROUP_LT_MASK
3526 """"""""""""""""""""""""""""""
3528 A bit mask of ``bit index < TGSI_SEMANTIC_SUBGROUP_INVOCATION``, i.e.
3529 ``(1 << subgroup_invocation) - 1`` in arbitrary precision arithmetic.
3532 TGSI_SEMANTIC_VIEWPORT_MASK
3533 """""""""""""""""""""""""""
3535 A bit mask of viewports to broadcast the current primitive to. See
3536 GL_NV_viewport_array2 for more details.
3539 TGSI_SEMANTIC_TESS_DEFAULT_OUTER_LEVEL
3540 """"""""""""""""""""""""""""""""""""""
3542 A system value equal to the default_outer_level array set via set_tess_level.
3545 TGSI_SEMANTIC_TESS_DEFAULT_INNER_LEVEL
3546 """"""""""""""""""""""""""""""""""""""
3548 A system value equal to the default_inner_level array set via set_tess_level.
3551 Declaration Interpolate
3552 ^^^^^^^^^^^^^^^^^^^^^^^
3554 This token is only valid for fragment shader INPUT declarations.
3556 The Interpolate field specifies the way input is being interpolated by
3557 the rasterizer and is one of TGSI_INTERPOLATE_*.
3559 The Location field specifies the location inside the pixel that the
3560 interpolation should be done at, one of ``TGSI_INTERPOLATE_LOC_*``. Note that
3561 when per-sample shading is enabled, the implementation may choose to
3562 interpolate at the sample irrespective of the Location field.
3565 Declaration Sampler View
3566 ^^^^^^^^^^^^^^^^^^^^^^^^
3568 Follows Declaration token if file is TGSI_FILE_SAMPLER_VIEW.
3570 DCL SVIEW[#], resource, type(s)
3572 Declares a shader input sampler view and assigns it to a SVIEW[#]
3575 resource can be one of BUFFER, 1D, 2D, 3D, 1DArray and 2DArray.
3577 type must be 1 or 4 entries (if specifying on a per-component
3578 level) out of UNORM, SNORM, SINT, UINT and FLOAT.
3580 For TEX\* style texture sample opcodes (as opposed to SAMPLE\* opcodes
3581 which take an explicit SVIEW[#] source register), there may be optionally
3582 SVIEW[#] declarations. In this case, the SVIEW index is implied by the
3583 SAMP index, and there must be a corresponding SVIEW[#] declaration for
3584 each SAMP[#] declaration. Drivers are free to ignore this if they wish.
3585 But note in particular that some drivers need to know the sampler type
3586 (float/int/unsigned) in order to generate the correct code, so cases
3587 where integer textures are sampled, SVIEW[#] declarations should be
3590 NOTE: It is NOT legal to mix SAMPLE\* style opcodes and TEX\* opcodes
3593 Declaration Resource
3594 ^^^^^^^^^^^^^^^^^^^^
3596 Follows Declaration token if file is TGSI_FILE_RESOURCE.
3598 DCL RES[#], resource [, WR] [, RAW]
3600 Declares a shader input resource and assigns it to a RES[#]
3603 resource can be one of BUFFER, 1D, 2D, 3D, CUBE, 1DArray and
3606 If the RAW keyword is not specified, the texture data will be
3607 subject to conversion, swizzling and scaling as required to yield
3608 the specified data type from the physical data format of the bound
3611 If the RAW keyword is specified, no channel conversion will be
3612 performed: the values read for each of the channels (X,Y,Z,W) will
3613 correspond to consecutive words in the same order and format
3614 they're found in memory. No element-to-address conversion will be
3615 performed either: the value of the provided X coordinate will be
3616 interpreted in byte units instead of texel units. The result of
3617 accessing a misaligned address is undefined.
3619 Usage of the STORE opcode is only allowed if the WR (writable) flag
3622 Hardware Atomic Register File
3623 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
3625 Hardware atomics are declared as a 2D array with an optional array id.
3627 The first member of the dimension is the buffer resource the atomic
3629 The second member is a range into the buffer resource, either for
3630 one or multiple counters. If this is an array, the declaration will have
3633 Each counter is 4 bytes in size, and index and ranges are in counters not bytes.
3637 This declares two atomics, one at the start of the buffer and one in the
3642 DCL HWATOMIC[1][1..3], ARRAY(1)
3644 This declares 5 atomics, one in buffer 0 at 0,
3645 one in buffer 1 at 0, and an array of 3 atomics in
3646 the buffer 1, starting at 1.
3649 ^^^^^^^^^^^^^^^^^^^^^^^^
3651 Properties are general directives that apply to the whole TGSI program.
3656 Specifies the fragment shader TGSI_SEMANTIC_POSITION coordinate origin.
3657 The default value is UPPER_LEFT.
3659 If UPPER_LEFT, the position will be (0,0) at the upper left corner and
3660 increase downward and rightward.
3661 If LOWER_LEFT, the position will be (0,0) at the lower left corner and
3662 increase upward and rightward.
3664 OpenGL defaults to LOWER_LEFT, and is configurable with the
3665 GL_ARB_fragment_coord_conventions extension.
3667 DirectX 9/10 use UPPER_LEFT.
3669 FS_COORD_PIXEL_CENTER
3670 """""""""""""""""""""
3672 Specifies the fragment shader TGSI_SEMANTIC_POSITION pixel center convention.
3673 The default value is HALF_INTEGER.
3675 If HALF_INTEGER, the fractional part of the position will be 0.5
3676 If INTEGER, the fractional part of the position will be 0.0
3678 Note that this does not affect the set of fragments generated by
3679 rasterization, which is instead controlled by half_pixel_center in the
3682 OpenGL defaults to HALF_INTEGER, and is configurable with the
3683 GL_ARB_fragment_coord_conventions extension.
3685 DirectX 9 uses INTEGER.
3686 DirectX 10 uses HALF_INTEGER.
3688 FS_COLOR0_WRITES_ALL_CBUFS
3689 """"""""""""""""""""""""""
3690 Specifies that writes to the fragment shader color 0 are replicated to all
3691 bound cbufs. This facilitates OpenGL's fragColor output vs fragData[0] where
3692 fragData is directed to a single color buffer, but fragColor is broadcast.
3695 """"""""""""""""""""""""""
3696 If this property is set on the program bound to the shader stage before the
3697 fragment shader, user clip planes should have no effect (be disabled) even if
3698 that shader does not write to any clip distance outputs and the rasterizer's
3699 clip_plane_enable is non-zero.
3700 This property is only supported by drivers that also support shader clip
3702 This is useful for APIs that don't have UCPs and where clip distances written
3703 by a shader cannot be disabled.
3708 Specifies the number of times a geometry shader should be executed for each
3709 input primitive. Each invocation will have a different
3710 TGSI_SEMANTIC_INVOCATIONID system value set. If not specified, assumed to
3713 VS_WINDOW_SPACE_POSITION
3714 """"""""""""""""""""""""""
3715 If this property is set on the vertex shader, the TGSI_SEMANTIC_POSITION output
3716 is assumed to contain window space coordinates.
3717 Division of X,Y,Z by W and the viewport transformation are disabled, and 1/W is
3718 directly taken from the 4-th component of the shader output.
3719 Naturally, clipping is not performed on window coordinates either.
3720 The effect of this property is undefined if a geometry or tessellation shader
3726 The number of vertices written by the tessellation control shader. This
3727 effectively defines the patch input size of the tessellation evaluation shader
3733 This sets the tessellation primitive mode, one of ``PIPE_PRIM_TRIANGLES``,
3734 ``PIPE_PRIM_QUADS``, or ``PIPE_PRIM_LINES``. (Unlike in GL, there is no
3735 separate isolines settings, the regular lines is assumed to mean isolines.)
3740 This sets the spacing mode of the tessellation generator, one of
3741 ``PIPE_TESS_SPACING_*``.
3746 This sets the vertex order to be clockwise if the value is 1, or
3747 counter-clockwise if set to 0.
3752 If set to a non-zero value, this turns on point mode for the tessellator,
3753 which means that points will be generated instead of primitives.
3755 NUM_CLIPDIST_ENABLED
3756 """"""""""""""""""""
3758 How many clip distance scalar outputs are enabled.
3760 NUM_CULLDIST_ENABLED
3761 """"""""""""""""""""
3763 How many cull distance scalar outputs are enabled.
3765 FS_EARLY_DEPTH_STENCIL
3766 """"""""""""""""""""""
3768 Whether depth test, stencil test, and occlusion query should run before
3769 the fragment shader (regardless of fragment shader side effects). Corresponds
3770 to GLSL early_fragment_tests.
3775 Which shader stage will MOST LIKELY follow after this shader when the shader
3776 is bound. This is only a hint to the driver and doesn't have to be precise.
3777 Only set for VS and TES.
3779 CS_FIXED_BLOCK_WIDTH / HEIGHT / DEPTH
3780 """""""""""""""""""""""""""""""""""""
3782 Threads per block in each dimension, if known at compile time. If the block size
3783 is known all three should be at least 1. If it is unknown they should all be set
3789 The MUL TGSI operation (FP32 multiplication) will return 0 if either
3790 of the operands are equal to 0. That means that 0 * Inf = 0. This
3791 should be set the same way for an entire pipeline. Note that this
3792 applies not only to the literal MUL TGSI opcode, but all FP32
3793 multiplications implied by other operations, such as MAD, FMA, DP2,
3794 DP3, DP4, DST, LOG, LRP, and possibly others. If there is a
3795 mismatch between shaders, then it is unspecified whether this behavior
3798 FS_POST_DEPTH_COVERAGE
3799 """"""""""""""""""""""
3801 When enabled, the input for TGSI_SEMANTIC_SAMPLEMASK will exclude samples
3802 that have failed the depth/stencil tests. This is only valid when
3803 FS_EARLY_DEPTH_STENCIL is also specified.
3805 LAYER_VIEWPORT_RELATIVE
3806 """""""""""""""""""""""
3808 When enabled, the TGSI_SEMATNIC_LAYER output value is relative to the
3809 current viewport. This is especially useful in conjunction with
3810 TGSI_SEMANTIC_VIEWPORT_MASK.
3813 Texture Sampling and Texture Formats
3814 ------------------------------------
3816 This table shows how texture image components are returned as (x,y,z,w) tuples
3817 by TGSI texture instructions, such as :opcode:`TEX`, :opcode:`TXD`, and
3818 :opcode:`TXP`. For reference, OpenGL and Direct3D conventions are shown as
3821 +--------------------+--------------+--------------------+--------------+
3822 | Texture Components | Gallium | OpenGL | Direct3D 9 |
3823 +====================+==============+====================+==============+
3824 | R | (r, 0, 0, 1) | (r, 0, 0, 1) | (r, 1, 1, 1) |
3825 +--------------------+--------------+--------------------+--------------+
3826 | RG | (r, g, 0, 1) | (r, g, 0, 1) | (r, g, 1, 1) |
3827 +--------------------+--------------+--------------------+--------------+
3828 | RGB | (r, g, b, 1) | (r, g, b, 1) | (r, g, b, 1) |
3829 +--------------------+--------------+--------------------+--------------+
3830 | RGBA | (r, g, b, a) | (r, g, b, a) | (r, g, b, a) |
3831 +--------------------+--------------+--------------------+--------------+
3832 | A | (0, 0, 0, a) | (0, 0, 0, a) | (0, 0, 0, a) |
3833 +--------------------+--------------+--------------------+--------------+
3834 | L | (l, l, l, 1) | (l, l, l, 1) | (l, l, l, 1) |
3835 +--------------------+--------------+--------------------+--------------+
3836 | LA | (l, l, l, a) | (l, l, l, a) | (l, l, l, a) |
3837 +--------------------+--------------+--------------------+--------------+
3838 | I | (i, i, i, i) | (i, i, i, i) | N/A |
3839 +--------------------+--------------+--------------------+--------------+
3840 | UV | XXX TBD | (0, 0, 0, 1) | (u, v, 1, 1) |
3841 | | | [#envmap-bumpmap]_ | |
3842 +--------------------+--------------+--------------------+--------------+
3843 | Z | XXX TBD | (z, z, z, 1) | (0, z, 0, 1) |
3844 | | | [#depth-tex-mode]_ | |
3845 +--------------------+--------------+--------------------+--------------+
3846 | S | (s, s, s, s) | unknown | unknown |
3847 +--------------------+--------------+--------------------+--------------+
3849 .. [#envmap-bumpmap] http://www.opengl.org/registry/specs/ATI/envmap_bumpmap.txt
3850 .. [#depth-tex-mode] the default is (z, z, z, 1) but may also be (0, 0, 0, z)
3851 or (z, z, z, z) depending on the value of GL_DEPTH_TEXTURE_MODE.