r600: implement tg4 integer workaround. (v2)

This ports the texture gather integer workaround from radeonsi.

This fixes:
KHR-GL45.texture_gather.plain-gather-uint/int*

v2: add rect support, fix 2d array shadow
Reviewed-by: Roland Scheidegger <sroland@vmware.com> (on irc)
Signed-off-by: Dave Airlie <airlied@redhat.com>

diff --git a/src/gallium/drivers/r600/r600_shader.c b/src/gallium/drivers/r600/r600_shader.c
index 269d4f0..358fc4c 100644 (file)
--- a/src/gallium/drivers/r600/r600_shader.c
+++ b/src/gallium/drivers/r600/r600_shader.c
@@ -7497,6 +7497,168 @@ static int tgsi_tex(struct r600_shader_ctx *ctx)
                }
        }
 
+       if (inst->Instruction.Opcode == TGSI_OPCODE_TG4) {
+               /* Gather4 should follow the same rules as bilinear filtering, but the hardware
+                * incorrectly forces nearest filtering if the texture format is integer.
+                * The only effect it has on Gather4, which always returns 4 texels for
+                * bilinear filtering, is that the final coordinates are off by 0.5 of
+                * the texel size.
+                *
+                * The workaround is to subtract 0.5 from the unnormalized coordinates,
+                * or (0.5 / size) from the normalized coordinates.
+                */
+               if (inst->Texture.ReturnType == TGSI_RETURN_TYPE_SINT ||
+                   inst->Texture.ReturnType == TGSI_RETURN_TYPE_UINT) {
+                       int treg = r600_get_temp(ctx);
+
+                       /* mov array and comparison oordinate to temp_reg if needed */
+                       if ((inst->Texture.Texture == TGSI_TEXTURE_SHADOW2D ||
+                            inst->Texture.Texture == TGSI_TEXTURE_2D_ARRAY ||
+                            inst->Texture.Texture == TGSI_TEXTURE_SHADOW2D_ARRAY) && !src_loaded) {
+                               int end = inst->Texture.Texture == TGSI_TEXTURE_SHADOW2D_ARRAY ? 3 : 2;
+                               for (i = 2; i <= end; i++) {
+                                       memset(&alu, 0, sizeof(struct r600_bytecode_alu));
+                                       alu.op = ALU_OP1_MOV;
+                                       alu.dst.sel = ctx->temp_reg;
+                                       alu.dst.chan = i;
+                                       alu.dst.write = 1;
+                                       alu.last = (i == end);
+                                       r600_bytecode_src(&alu.src[0], &ctx->src[0], i);
+                                       r = r600_bytecode_add_alu(ctx->bc, &alu);
+                                       if (r)
+                                               return r;
+                               }
+                       }
+
+                       if (inst->Texture.Texture == TGSI_TEXTURE_RECT ||
+                           inst->Texture.Texture == TGSI_TEXTURE_SHADOWRECT) {
+                               for (i = 0; i < 2; i++) {
+                                       memset(&alu, 0, sizeof(struct r600_bytecode_alu));
+                                       alu.op = ALU_OP2_ADD;
+                                       alu.dst.sel = ctx->temp_reg;
+                                       alu.dst.chan = i;
+                                       alu.dst.write = 1;
+                                       alu.last = i == 1;
+                                       if (src_loaded) {
+                                               alu.src[0].sel = ctx->temp_reg;
+                                               alu.src[0].chan = i;
+                                       } else
+                                               r600_bytecode_src(&alu.src[0], &ctx->src[0], i);
+                                       alu.src[1].sel = V_SQ_ALU_SRC_0_5;
+                                       alu.src[1].neg = 1;
+                                       r = r600_bytecode_add_alu(ctx->bc, &alu);
+                                       if (r)
+                                               return r;
+                               }
+                       } else {
+                               /* execute a TXQ */
+                               memset(&tex, 0, sizeof(struct r600_bytecode_tex));
+                               tex.op = FETCH_OP_GET_TEXTURE_RESINFO;
+                               tex.sampler_id = tgsi_tex_get_src_gpr(ctx, sampler_src_reg);
+                               tex.sampler_index_mode = sampler_index_mode;
+                               tex.resource_id = tex.sampler_id + R600_MAX_CONST_BUFFERS;
+                               tex.resource_index_mode = sampler_index_mode;
+                               tex.dst_gpr = treg;
+                               tex.src_sel_x = 4;
+                               tex.src_sel_y = 4;
+                               tex.src_sel_z = 4;
+                               tex.src_sel_w = 4;
+                               tex.dst_sel_x = 0;
+                               tex.dst_sel_y = 1;
+                               tex.dst_sel_z = 7;
+                               tex.dst_sel_w = 7;
+                               r = r600_bytecode_add_tex(ctx->bc, &tex);
+                               if (r)
+                                       return r;
+
+                               /* coord.xy = -0.5 * (1.0/int_to_flt(size)) + coord.xy */
+                               if (ctx->bc->chip_class == CAYMAN) {
+                                       /* */
+                                       for (i = 0; i < 2; i++) {
+                                               memset(&alu, 0, sizeof(struct r600_bytecode_alu));
+                                               alu.op = ALU_OP1_INT_TO_FLT;
+                                               alu.dst.sel = treg;
+                                               alu.dst.chan = i;
+                                               alu.dst.write = 1;
+                                               alu.src[0].sel = treg;
+                                               alu.src[0].chan = i;
+                                               alu.last = (i == 1) ? 1 : 0;
+                                               r = r600_bytecode_add_alu(ctx->bc, &alu);
+                                               if (r)
+                                                       return r;
+                                       }
+                                       for (j = 0; j < 2; j++) {
+                                               for (i = 0; i < 3; i++) {
+                                                       memset(&alu, 0, sizeof(struct r600_bytecode_alu));
+                                                       alu.op = ALU_OP1_RECIP_IEEE;
+                                                       alu.src[0].sel = treg;
+                                                       alu.src[0].chan = j;
+                                                       alu.dst.sel = treg;
+                                                       alu.dst.chan = i;
+                                                       if (i == 2)
+                                                               alu.last = 1;
+                                                       if (i == j)
+                                                               alu.dst.write = 1;
+                                                       r = r600_bytecode_add_alu(ctx->bc, &alu);
+                                                       if (r)
+                                                               return r;
+                                               }
+                                       }
+                               } else {
+                                       for (i = 0; i < 2; i++) {
+                                               memset(&alu, 0, sizeof(struct r600_bytecode_alu));
+                                               alu.op = ALU_OP1_INT_TO_FLT;
+                                               alu.dst.sel = treg;
+                                               alu.dst.chan = i;
+                                               alu.dst.write = 1;
+                                               alu.src[0].sel = treg;
+                                               alu.src[0].chan = i;
+                                               alu.last = 1;
+                                               r = r600_bytecode_add_alu(ctx->bc, &alu);
+                                               if (r)
+                                                       return r;
+                                       }
+                                       for (i = 0; i < 2; i++) {
+                                               memset(&alu, 0, sizeof(struct r600_bytecode_alu));
+                                               alu.op = ALU_OP1_RECIP_IEEE;
+                                               alu.src[0].sel = treg;
+                                               alu.src[0].chan = i;
+                                               alu.dst.sel = treg;
+                                               alu.dst.chan = i;
+                                               alu.last = 1;
+                                               alu.dst.write = 1;
+                                               r = r600_bytecode_add_alu(ctx->bc, &alu);
+                                               if (r)
+                                                       return r;
+                                       }
+                               }
+                               for (i = 0; i < 2; i++) {
+                                       memset(&alu, 0, sizeof(struct r600_bytecode_alu));
+                                       alu.op = ALU_OP3_MULADD;
+                                       alu.is_op3 = 1;
+                                       alu.dst.sel = ctx->temp_reg;
+                                       alu.dst.chan = i;
+                                       alu.dst.write = 1;
+                                       alu.last = i == 1;
+                                       alu.src[0].sel = treg;
+                                       alu.src[0].chan = i;
+                                       alu.src[1].sel = V_SQ_ALU_SRC_0_5;
+                                       alu.src[1].neg = 1;
+                                       if (src_loaded) {
+                                               alu.src[2].sel = ctx->temp_reg;
+                                               alu.src[2].chan = i;
+                                       } else
+                                               r600_bytecode_src(&alu.src[2], &ctx->src[0], i);
+                                       r = r600_bytecode_add_alu(ctx->bc, &alu);
+                                       if (r)
+                                               return r;
+                               }
+                       }
+                       src_loaded = TRUE;
+                       src_gpr = ctx->temp_reg;
+               }
+       }
+
        if (src_requires_loading && !src_loaded) {
                for (i = 0; i < 4; i++) {
                        memset(&alu, 0, sizeof(struct r600_bytecode_alu));