From 48f5c34301e9f03a18b928251180c82b8c7571d1 Mon Sep 17 00:00:00 2001 From: Iago Toral Quiroga Date: Wed, 31 Jul 2019 09:47:08 +0200 Subject: [PATCH] nir: add a pass to clamp gl_PointSize to a range The OpenGL and OpenGL ES specs require that implementations clamp the value of gl_PointSize to an implementation-depedent range. This pass is useful for any GPU hardware that doesn't do this automatically for either one or both sides of the range, such as V3D. v2: - Turn into a generic NIR pass (Eric). - Make the pass work before lower I/O so we can use the deref variable to inspect if we are writing to gl_PointSize (Eric). - Make the pass take the range to clamp as parameter and allow it to clamp to both sides of the range or just one side. - Make the pass report progress. v3: - Fix copyright header (Eric) - use fmin/fmax instead of bcsel to clamp (Eric) Reviewed-by: Eric Anholt --- src/compiler/nir/meson.build | 1 + src/compiler/nir/nir.h | 2 + src/compiler/nir/nir_lower_point_size.c | 124 ++++++++++++++++++++++++ 3 files changed, 127 insertions(+) create mode 100644 src/compiler/nir/nir_lower_point_size.c diff --git a/src/compiler/nir/meson.build b/src/compiler/nir/meson.build index 9b527b22f7c..336bf2ef543 100644 --- a/src/compiler/nir/meson.build +++ b/src/compiler/nir/meson.build @@ -148,6 +148,7 @@ files_libnir = files( 'nir_lower_passthrough_edgeflags.c', 'nir_lower_patch_vertices.c', 'nir_lower_phis_to_scalar.c', + 'nir_lower_point_size.c', 'nir_lower_regs_to_ssa.c', 'nir_lower_returns.c', 'nir_lower_scratch.c', diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h index 314b696f738..09a3be5527e 100644 --- a/src/compiler/nir/nir.h +++ b/src/compiler/nir/nir.h @@ -3886,6 +3886,8 @@ bool nir_lower_doubles(nir_shader *shader, const nir_shader *softfp64, nir_lower_doubles_options options); bool nir_lower_pack(nir_shader *shader); +bool nir_lower_point_size(nir_shader *shader, float min, float max); + typedef enum { nir_lower_interpolation_at_sample = (1 << 1), nir_lower_interpolation_at_offset = (1 << 2), diff --git a/src/compiler/nir/nir_lower_point_size.c b/src/compiler/nir/nir_lower_point_size.c new file mode 100644 index 00000000000..d614bb21ec5 --- /dev/null +++ b/src/compiler/nir/nir_lower_point_size.c @@ -0,0 +1,124 @@ +/* + * Copyright © 2019 Raspberry Pi + * + * 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 "nir_builder.h" + +/** @file nir_lower_point_size.c + * + * The OpenGL spec requires that implementations clamp gl_PointSize to an + * implementation-dependant point size range. The OpenGL ES 3.0 spec further + * requires that this range must match GL_ALIASED_POINT_SIZE_RANGE. + * Some hardware such as V3D don't clamp to a valid range automatically so + * the driver must clamp the point size written by the shader manually to a + * valid range. + */ + +static void +lower_point_size_instr(nir_builder *b, nir_instr *psiz_instr, + float min, float max) +{ + b->cursor = nir_before_instr(psiz_instr); + + nir_intrinsic_instr *instr = nir_instr_as_intrinsic(psiz_instr); + + /* Some fixed function vertex programs generate PSIZ as a vec4 + * instead of a scalar, where the actual point size is stored in the + * first component. + */ + assert(instr->src[1].is_ssa); + nir_ssa_def *psiz = nir_channel(b, instr->src[1].ssa, 0); + + if (min > 0.0f) + psiz = nir_fmax(b, psiz, nir_imm_float(b, min)); + + if (max > 0.0f) + psiz = nir_fmin(b, psiz, nir_imm_float(b, max)); + + nir_ssa_def *src_chans[4]; + src_chans[0] = psiz; + for (int i = 1; i < instr->src[1].ssa->num_components; i++) + src_chans[i] = nir_channel(b, instr->src[1].ssa, i); + nir_ssa_def *lowered_src = + nir_vec(b, src_chans, instr->src[1].ssa->num_components); + + nir_instr_rewrite_src(&instr->instr, &instr->src[1], + nir_src_for_ssa(lowered_src)); +} + +static bool +instr_is_point_size(const nir_instr *instr) +{ + if (instr->type != nir_instr_type_intrinsic) + return false; + + nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr); + if (intr->intrinsic != nir_intrinsic_store_deref) + return false; + + nir_deref_instr *deref = nir_src_as_deref(intr->src[0]); + nir_variable *var = nir_deref_instr_get_variable(deref); + if (var->data.location != VARYING_SLOT_PSIZ) + return false; + + return true; +} + +/** + * Clamps gl_PointSize to the range [min, max]. If either min or max are not + * greater than 0 then no clamping is done for that side of the range. + */ +bool +nir_lower_point_size(nir_shader *s, float min, float max) +{ + assert(s->info.stage != MESA_SHADER_FRAGMENT && + s->info.stage != MESA_SHADER_COMPUTE); + + assert(min > 0.0f || max > 0.0f); + assert(min <= 0.0f || max <= 0.0f || min <= max); + + bool progress = false; + nir_foreach_function(function, s) { + if (!function->impl) + continue; + + nir_builder b; + nir_builder_init(&b, function->impl); + + nir_foreach_block(block, function->impl) { + nir_foreach_instr_safe(instr, block) { + if (instr_is_point_size(instr)) { + lower_point_size_instr(&b, instr, min, max); + progress = true; + } + } + } + + if (progress) { + nir_metadata_preserve(function->impl, + nir_metadata_block_index | + nir_metadata_dominance); + } + } + + return progress; +} -- 2.30.2