From 651a3da1b59446a6e392321d1dbbc1891a0544a8 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Timur=20Krist=C3=B3f?= Date: Thu, 1 Apr 2021 12:43:31 +0200 Subject: [PATCH] ac/nir: Add a NIR port of ac_llvm_cull. MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit The algorithms were originally implemented by Marek Olšák, hence the copyright to AMD. This commit just ports the LLVM based implementation to NIR, using the new intrinsics added earlier. Signed-off-by: Timur Kristóf Reviewed-by: Daniel Schürmann Part-of: --- src/amd/common/ac_nir.h | 10 +++ src/amd/common/ac_nir_cull.c | 157 +++++++++++++++++++++++++++++++++++++++++++ src/amd/common/meson.build | 1 + 3 files changed, 168 insertions(+) create mode 100644 src/amd/common/ac_nir_cull.c diff --git a/src/amd/common/ac_nir.h b/src/amd/common/ac_nir.h index 89512b8..1ce615b 100644 --- a/src/amd/common/ac_nir.h +++ b/src/amd/common/ac_nir.h @@ -28,12 +28,17 @@ #include "nir.h" #include "ac_shader_args.h" +#include "ac_shader_util.h" #include "amd_family.h" #ifdef __cplusplus extern "C" { #endif +/* Forward declaration of nir_builder so we don't have to include nir_builder.h here */ +struct nir_builder; +typedef struct nir_builder nir_builder; + void ac_nir_lower_ls_outputs_to_mem(nir_shader *ls, bool tcs_in_out_eq, @@ -112,6 +117,11 @@ ac_nir_lower_ngg_gs(nir_shader *shader, unsigned gs_total_out_vtx_bytes, bool provoking_vtx_last); +nir_ssa_def * +ac_nir_cull_triangle(nir_builder *b, + nir_ssa_def *initially_accepted, + nir_ssa_def *pos[3][4]); + #ifdef __cplusplus } #endif diff --git a/src/amd/common/ac_nir_cull.c b/src/amd/common/ac_nir_cull.c new file mode 100644 index 0000000..a5adf2a --- /dev/null +++ b/src/amd/common/ac_nir_cull.c @@ -0,0 +1,157 @@ +/* + * Copyright 2019 Advanced Micro Devices, Inc. + * Copyright 2021 Valve Corporation + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the "Software"), + * to deal in the Software without restriction, including without limitation + * the rights to use, copy, modify, merge, publish, distribute, sublicense, + * and/or sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice (including the next + * paragraph) shall be included in all copies or substantial portions of the + * Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS + * IN THE SOFTWARE. + * + */ + +#include "ac_nir.h" +#include "nir_builder.h" + +/* This code is adapted from ac_llvm_cull.c, hence the copyright to AMD. */ + +typedef struct +{ + nir_ssa_def *w_reflection; + nir_ssa_def *w_accepted; + nir_ssa_def *all_w_positive; + nir_ssa_def *any_w_negative; +} position_w_info; + +static void +analyze_position_w(nir_builder *b, nir_ssa_def *pos[3][4], position_w_info *w_info) +{ + nir_ssa_def *all_w_negative = nir_imm_bool(b, true); + + w_info->w_reflection = nir_imm_bool(b, false); + w_info->any_w_negative = nir_imm_bool(b, false); + + for (unsigned i = 0; i < 3; ++i) { + nir_ssa_def *neg_w = nir_flt(b, pos[i][3], nir_imm_float(b, 0.0f)); + w_info->w_reflection = nir_ixor(b, neg_w, w_info->w_reflection); + w_info->any_w_negative = nir_ior(b, neg_w, w_info->any_w_negative); + all_w_negative = nir_iand(b, neg_w, all_w_negative); + } + + w_info->all_w_positive = nir_inot(b, w_info->any_w_negative); + w_info->w_accepted = nir_inot(b, all_w_negative); +} + +static nir_ssa_def * +cull_face(nir_builder *b, nir_ssa_def *pos[3][4], const position_w_info *w_info) +{ + nir_ssa_def *det_t0 = nir_fsub(b, pos[2][0], pos[0][0]); + nir_ssa_def *det_t1 = nir_fsub(b, pos[1][1], pos[0][1]); + nir_ssa_def *det_t2 = nir_fsub(b, pos[0][0], pos[1][0]); + nir_ssa_def *det_t3 = nir_fsub(b, pos[0][1], pos[2][1]); + nir_ssa_def *det_p0 = nir_fmul(b, det_t0, det_t1); + nir_ssa_def *det_p1 = nir_fmul(b, det_t2, det_t3); + nir_ssa_def *det = nir_fsub(b, det_p0, det_p1); + + det = nir_bcsel(b, w_info->w_reflection, nir_fneg(b, det), det); + + nir_ssa_def *front_facing_cw = nir_flt(b, det, nir_imm_float(b, 0.0f)); + nir_ssa_def *front_facing_ccw = nir_flt(b, nir_imm_float(b, 0.0f), det); + nir_ssa_def *ccw = nir_build_load_cull_ccw_amd(b); + nir_ssa_def *front_facing = nir_bcsel(b, ccw, front_facing_ccw, front_facing_cw); + nir_ssa_def *cull_front = nir_build_load_cull_front_face_enabled_amd(b); + nir_ssa_def *cull_back = nir_build_load_cull_back_face_enabled_amd(b); + + return nir_inot(b, nir_bcsel(b, front_facing, cull_front, cull_back)); +} + +static nir_ssa_def * +cull_bbox(nir_builder *b, nir_ssa_def *pos[3][4], nir_ssa_def *accepted, const position_w_info *w_info) +{ + nir_ssa_def *bbox_accepted = NULL; + nir_ssa_def *try_cull_bbox = nir_iand(b, accepted, w_info->all_w_positive); + + nir_if *if_cull_bbox = nir_push_if(b, try_cull_bbox); + { + nir_ssa_def *bbox_min[3] = {0}, *bbox_max[3] = {0}; + + for (unsigned chan = 0; chan < 2; ++chan) { + bbox_min[chan] = nir_fmin(b, pos[0][chan], nir_fmin(b, pos[1][chan], pos[2][chan])); + bbox_max[chan] = nir_fmax(b, pos[0][chan], nir_fmax(b, pos[1][chan], pos[2][chan])); + } + + nir_ssa_def *vp_scale[2] = { nir_build_load_viewport_x_scale(b), nir_build_load_viewport_y_scale(b), }; + nir_ssa_def *vp_translate[2] = { nir_build_load_viewport_x_offset(b), nir_build_load_viewport_y_offset(b), }; + nir_ssa_def *prim_outside_view = nir_imm_false(b); + + /* Frustrum culling - eliminate triangles that are fully outside the view. */ + for (unsigned chan = 0; chan < 2; ++chan) { + prim_outside_view = nir_ior(b, prim_outside_view, nir_flt(b, bbox_max[chan], nir_imm_float(b, -1.0f))); + prim_outside_view = nir_ior(b, prim_outside_view, nir_flt(b, nir_imm_float(b, 1.0f), bbox_min[chan])); + } + + nir_ssa_def *prim_is_small = NULL; + nir_ssa_def *prim_is_small_else = nir_imm_false(b); + + /* Small primitive filter - eliminate triangles that are too small to affect a sample. */ + nir_if *if_cull_small_prims = nir_push_if(b, nir_build_load_cull_small_primitives_enabled_amd(b)); + { + nir_ssa_def *small_prim_precision = nir_build_load_cull_small_prim_precision_amd(b); + prim_is_small = nir_imm_false(b); + + for (unsigned chan = 0; chan < 2; ++chan) { + /* Convert the position to screen-space coordinates. */ + nir_ssa_def *min = nir_ffma(b, bbox_min[chan], vp_scale[chan], vp_translate[chan]); + nir_ssa_def *max = nir_ffma(b, bbox_max[chan], vp_scale[chan], vp_translate[chan]); + + /* Scale the bounding box according to precision. */ + min = nir_fsub(b, min, small_prim_precision); + max = nir_fadd(b, max, small_prim_precision); + + /* Determine if the bbox intersects the sample point, by checking if the min and max round to the same int. */ + min = nir_fround_even(b, min); + max = nir_fround_even(b, max); + + nir_ssa_def *rounded_to_eq = nir_feq(b, min, max); + prim_is_small = nir_ior(b, prim_is_small, rounded_to_eq); + } + } + nir_pop_if(b, if_cull_small_prims); + + prim_is_small = nir_if_phi(b, prim_is_small, prim_is_small_else); + nir_ssa_def *prim_invisible = nir_ior(b, prim_outside_view, prim_is_small); + + bbox_accepted = nir_inot(b, prim_invisible); + } + nir_pop_if(b, if_cull_bbox); + return nir_if_phi(b, bbox_accepted, accepted); +} + +nir_ssa_def * +ac_nir_cull_triangle(nir_builder *b, + nir_ssa_def *initially_accepted, + nir_ssa_def *pos[3][4]) +{ + position_w_info w_info = {0}; + analyze_position_w(b, pos, &w_info); + + nir_ssa_def *accepted = initially_accepted; + accepted = nir_iand(b, accepted, w_info.w_accepted); + accepted = nir_iand(b, accepted, cull_face(b, pos, &w_info)); + accepted = nir_iand(b, accepted, cull_bbox(b, pos, accepted, &w_info)); + + return accepted; +} diff --git a/src/amd/common/meson.build b/src/amd/common/meson.build index 8edd357c..09a1ed1 100644 --- a/src/amd/common/meson.build +++ b/src/amd/common/meson.build @@ -89,6 +89,7 @@ amd_common_files = files( 'ac_rgp_elf_object_pack.c', 'ac_nir.c', 'ac_nir.h', + 'ac_nir_cull.c', 'ac_nir_lower_esgs_io_to_mem.c', 'ac_nir_lower_tess_io_to_mem.c', 'ac_nir_lower_ngg.c', -- 2.7.4