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// Copyright 2022 The Dawn & Tint Authors
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this
// list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
//
// 3. Neither the name of the copyright holder nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "src/tint/lang/glsl/writer/ast_raise/combine_samplers.h"
#include <string>
#include <unordered_map>
#include <utility>
#include <vector>
#include "src/tint/lang/wgsl/program/clone_context.h"
#include "src/tint/lang/wgsl/program/program_builder.h"
#include "src/tint/lang/wgsl/resolver/resolve.h"
#include "src/tint/lang/wgsl/sem/function.h"
#include "src/tint/lang/wgsl/sem/statement.h"
#include "src/tint/utils/containers/map.h"
TINT_INSTANTIATE_TYPEINFO(tint::glsl::writer::CombineSamplers);
TINT_INSTANTIATE_TYPEINFO(tint::glsl::writer::CombineSamplers::BindingInfo);
namespace {
bool IsGlobal(const tint::sem::VariablePair& pair) {
return (!pair.first || tint::Is<tint::sem::GlobalVariable>(pair.first)) &&
(!pair.second || tint::Is<tint::sem::GlobalVariable>(pair.second));
}
} // namespace
namespace tint::glsl::writer {
using namespace tint::core::number_suffixes; // NOLINT
CombineSamplers::BindingInfo::BindingInfo(const BindingMap& map, const BindingPoint& placeholder)
: binding_map(map), placeholder_binding_point(placeholder) {}
CombineSamplers::BindingInfo::BindingInfo(const BindingInfo& other) = default;
CombineSamplers::BindingInfo::~BindingInfo() = default;
/// PIMPL state for the transform
struct CombineSamplers::State {
/// The source program
const Program& src;
/// The target program builder
ProgramBuilder b;
/// The clone context
program::CloneContext ctx = {&b, &src, /* auto_clone_symbols */ true};
/// The binding info
const BindingInfo* binding_info;
/// Map from a texture/sampler pair to the corresponding combined sampler
/// variable
using CombinedTextureSamplerMap = std::unordered_map<sem::VariablePair, const ast::Variable*>;
/// A map of all global texture/sampler variable pairs to the global
/// combined sampler variable that will replace it.
CombinedTextureSamplerMap global_combined_texture_samplers_;
/// A map of all texture/sampler variable pairs that contain a function
/// parameter to the combined sampler function paramter that will replace it.
std::unordered_map<const sem::Function*, CombinedTextureSamplerMap>
function_combined_texture_samplers_;
/// Placeholder global samplers used when a function contains texture-only
/// references (one comparison sampler, one regular). These are also used as
/// temporary sampler parameters to the texture builtins to satisfy the WGSL
/// resolver, but are then ignored and removed by the GLSL writer.
const ast::Variable* placeholder_samplers_[2] = {};
/// Group and binding attributes used by all combined sampler globals.
/// Group 0 and binding 0 are used, with collisions disabled.
/// @returns the newly-created attribute list
auto Attributes() const {
Vector<const ast::Attribute*, 3> attributes{ctx.dst->Group(0_a), ctx.dst->Binding(0_a)};
attributes.Push(ctx.dst->Disable(ast::DisabledValidation::kBindingPointCollision));
return attributes;
}
/// Constructor
/// @param program the source program
/// @param info the binding map information
State(const Program& program, const BindingInfo* info) : src(program), binding_info(info) {}
/// Creates a combined sampler global variables.
/// (Note this is actually a Texture node at the AST level, but it will be
/// written as the corresponding sampler (eg., sampler2D) on GLSL output.)
/// @param texture_var the texture (global) variable
/// @param sampler_var the sampler (global) variable
/// @param name the default name to use (may be overridden by map lookup)
/// @returns the newly-created global variable
const ast::Variable* CreateCombinedGlobal(const sem::Variable* texture_var,
const sem::Variable* sampler_var,
std::string name) {
SamplerTexturePair bp_pair;
bp_pair.texture_binding_point =
texture_var ? *texture_var->As<sem::GlobalVariable>()->Attributes().binding_point
: binding_info->placeholder_binding_point;
bp_pair.sampler_binding_point =
sampler_var ? *sampler_var->As<sem::GlobalVariable>()->Attributes().binding_point
: binding_info->placeholder_binding_point;
auto it = binding_info->binding_map.find(bp_pair);
if (it != binding_info->binding_map.end()) {
name = it->second;
}
ast::Type type = CreateCombinedASTTypeFor(texture_var, sampler_var);
Symbol symbol = ctx.dst->Symbols().New(name);
return ctx.dst->GlobalVar(symbol, type, Attributes());
}
/// Creates placeholder global sampler variables.
/// @param kind the sampler kind to create for
/// @returns the newly-created global variable
const ast::Variable* CreatePlaceholder(core::type::SamplerKind kind) {
ast::Type type = ctx.dst->ty.sampler(kind);
const char* name = kind == core::type::SamplerKind::kComparisonSampler
? "placeholder_comparison_sampler"
: "placeholder_sampler";
Symbol symbol = ctx.dst->Symbols().New(name);
return ctx.dst->GlobalVar(symbol, type, Attributes());
}
/// Creates Identifier for a given texture and sampler variable pair.
/// Depth textures with no samplers are turned into the corresponding
/// f32 texture (e.g., texture_depth_2d -> texture_2d<f32>).
/// Either texture or sampler could be nullptr, but cannot be nullptr at the same time.
/// The texture can only be nullptr, when the sampler is a dangling function parameter.
/// @param texture the texture variable of interest
/// @param sampler the texture variable of interest
/// @returns the newly-created type
ast::Type CreateCombinedASTTypeFor(const sem::Variable* texture, const sem::Variable* sampler) {
if (texture) {
const core::type::Type* texture_type = texture->Type()->UnwrapRef();
const core::type::DepthTexture* depth = texture_type->As<core::type::DepthTexture>();
if (depth && !sampler) {
return ctx.dst->ty.sampled_texture(depth->dim(), ctx.dst->ty.f32());
} else {
return CreateASTTypeFor(ctx, texture_type);
}
} else {
TINT_ASSERT(sampler != nullptr);
const core::type::Type* sampler_type = sampler->Type()->UnwrapRef();
return CreateASTTypeFor(ctx, sampler_type);
}
}
/// Insert a new texture/sampler pair into the combined samplers maps (global or local, as
/// appropriate). If local, also add a function parameter to "params".
/// @param pair the texture/sampler pair to insert
/// @param fn the function scope in which to insert (if local)
/// @param params the calling function's parameter list to modify (if local)
void InsertPair(sem::VariablePair pair,
const sem::Function* fn,
tint::Vector<const ast::Parameter*, 8>* params) {
const sem::Variable* texture_var = pair.first;
const sem::Variable* sampler_var = pair.second;
std::string name = "";
if (texture_var) {
name = texture_var->Declaration()->name->symbol.Name();
}
if (sampler_var) {
if (!name.empty()) {
name += "_";
}
name += sampler_var->Declaration()->name->symbol.Name();
}
if (IsGlobal(pair)) {
// Both texture and sampler are global; add a new global variable
// to represent the combined sampler (if not already created).
GetOrCreate(global_combined_texture_samplers_, pair,
[&] { return CreateCombinedGlobal(texture_var, sampler_var, name); });
} else {
// Either texture or sampler (or both) is a function parameter;
// add a new function parameter to represent the combined sampler.
ast::Type type = CreateCombinedASTTypeFor(texture_var, sampler_var);
auto* var = ctx.dst->Param(ctx.dst->Symbols().New(name), type);
params->Push(var);
function_combined_texture_samplers_[fn][pair] = var;
}
}
/// For a given texture, find any texture/sampler pair with a non-null sampler in the given
/// function scope.
/// @param texture_var the texture variable of interest
/// @param fn the function scope in which to search
/// @returns the full pair, if found
const sem::VariablePair* FindFullTextureSamplerPair(const sem::Variable* texture_var,
const sem::Function* fn) {
for (auto pairIter = fn->TextureSamplerPairs().begin();
pairIter != fn->TextureSamplerPairs().end(); pairIter++) {
if (pairIter->first == texture_var && pairIter->second) {
return pairIter;
}
}
return nullptr;
}
/// Runs the transform
/// @returns the new program or SkipTransform if the transform is not required
ApplyResult Run() {
auto& sem = ctx.src->Sem();
// Remove all texture and sampler global variables. These will be replaced
// by combined samplers.
for (auto* global : ctx.src->AST().GlobalVariables()) {
auto* global_sem = sem.Get(global)->As<sem::GlobalVariable>();
auto* type = ctx.src->TypeOf(global->type);
if (tint::IsAnyOf<core::type::Texture, core::type::Sampler>(type) &&
!type->Is<core::type::StorageTexture>()) {
ctx.Remove(ctx.src->AST().GlobalDeclarations(), global);
} else if (auto binding_point = global_sem->Attributes().binding_point) {
if (binding_point->group == 0 && binding_point->binding == 0) {
auto* attribute =
ctx.dst->Disable(ast::DisabledValidation::kBindingPointCollision);
ctx.InsertFront(global->attributes, attribute);
}
}
}
// Rewrite all function signatures to use combined samplers, and remove
// separate textures & samplers. Create new combined globals where found.
ctx.ReplaceAll([&](const ast::Function* ast_fn) -> const ast::Function* {
if (auto* fn = sem.Get(ast_fn)) {
auto pairs = fn->TextureSamplerPairs();
if (pairs.IsEmpty()) {
return nullptr;
}
Vector<const ast::Parameter*, 8> params;
for (auto pair : fn->TextureSamplerPairs()) {
if (!pair.second) {
continue;
}
InsertPair(pair, fn, &params);
}
for (auto pair : fn->TextureSamplerPairs()) {
if (pair.second) {
continue;
}
// Look for another pair with a non-null sampler.
// NOTE: this is O(N^2) in the number of pairs, since
// FindFullTextureSamplerPair() also loops over all pairs. If this proves
// problematic, it could be optimized.
if (const sem::VariablePair* fullPair =
FindFullTextureSamplerPair(pair.first, fn)) {
if (IsGlobal(pair)) {
global_combined_texture_samplers_[pair] =
global_combined_texture_samplers_[*fullPair];
} else {
auto* var = function_combined_texture_samplers_[fn][*fullPair];
function_combined_texture_samplers_[fn][pair] = var;
}
} else {
InsertPair(pair, fn, &params);
}
}
// Filter out separate textures and samplers from the original
// function signature.
for (auto* param : fn->Parameters()) {
if (!param->Type()->IsAnyOf<core::type::Texture, core::type::Sampler>()) {
params.Push(ctx.Clone(param->Declaration()));
}
}
// Create a new function signature that differs only in the parameter
// list.
auto name = ctx.Clone(ast_fn->name);
auto return_type = ctx.Clone(ast_fn->return_type);
auto* body = ctx.Clone(ast_fn->body);
auto attributes = ctx.Clone(ast_fn->attributes);
auto return_type_attributes = ctx.Clone(ast_fn->return_type_attributes);
return ctx.dst->create<ast::Function>(name, params, return_type, body,
std::move(attributes),
std::move(return_type_attributes));
}
return nullptr;
});
// Replace all function call expressions containing texture or
// sampler parameters to use the current function's combined samplers or
// the combined global samplers, as appropriate.
ctx.ReplaceAll([&](const ast::CallExpression* expr) -> const ast::Expression* {
if (auto* call = sem.Get(expr)->UnwrapMaterialize()->As<sem::Call>()) {
Vector<const ast::Expression*, 8> args;
// Replace all texture builtin calls.
if (auto* builtin = call->Target()->As<sem::BuiltinFn>()) {
const auto& signature = builtin->Signature();
auto sampler_index = signature.IndexOf(core::ParameterUsage::kSampler);
auto texture_index = signature.IndexOf(core::ParameterUsage::kTexture);
if (texture_index == -1) {
return nullptr;
}
const sem::ValueExpression* texture =
call->Arguments()[static_cast<size_t>(texture_index)];
// We don't want to combine storage textures with anything, since
// they never have associated samplers in GLSL.
if (texture->Type()->UnwrapRef()->Is<core::type::StorageTexture>()) {
return nullptr;
}
const sem::ValueExpression* sampler =
sampler_index != -1 ? call->Arguments()[static_cast<size_t>(sampler_index)]
: nullptr;
auto* texture_var = texture->UnwrapLoad()->As<sem::VariableUser>()->Variable();
auto* sampler_var =
sampler ? sampler->UnwrapLoad()->As<sem::VariableUser>()->Variable()
: nullptr;
sem::VariablePair new_pair(texture_var, sampler_var);
for (auto* arg : expr->args) {
auto* type = ctx.src->TypeOf(arg)->UnwrapRef();
if (type->Is<core::type::Texture>()) {
const ast::Variable* var =
IsGlobal(new_pair)
? global_combined_texture_samplers_[new_pair]
: function_combined_texture_samplers_[call->Stmt()->Function()]
[new_pair];
args.Push(ctx.dst->Expr(var->name->symbol));
} else if (auto* sampler_type = type->As<core::type::Sampler>()) {
core::type::SamplerKind kind = sampler_type->kind();
int index = (kind == core::type::SamplerKind::kSampler) ? 0 : 1;
const ast::Variable*& p = placeholder_samplers_[index];
if (!p) {
p = CreatePlaceholder(kind);
}
args.Push(ctx.dst->Expr(p->name->symbol));
} else {
args.Push(ctx.Clone(arg));
}
}
const ast::Expression* value = ctx.dst->Call(ctx.Clone(expr->target), args);
if (builtin->Fn() == wgsl::BuiltinFn::kTextureLoad &&
texture_var->Type()->UnwrapRef()->Is<core::type::DepthTexture>() &&
!call->Stmt()->Declaration()->Is<ast::CallStatement>()) {
value = ctx.dst->MemberAccessor(value, "x");
}
return value;
}
// Replace all function calls.
if (auto* callee = call->Target()->As<sem::Function>()) {
auto make_arg = [&](const sem::Variable* texture_var,
const sem::Variable* sampler_var) {
if (auto* param = tint::As<sem::Parameter>(texture_var)) {
const sem::ValueExpression* texture = call->Arguments()[param->Index()];
texture_var =
texture->UnwrapLoad()->As<sem::VariableUser>()->Variable();
}
if (auto* param = tint::As<sem::Parameter>(sampler_var)) {
const sem::ValueExpression* sampler = call->Arguments()[param->Index()];
sampler_var =
sampler->UnwrapLoad()->As<sem::VariableUser>()->Variable();
}
sem::VariablePair new_pair(texture_var, sampler_var);
// If both texture and sampler are (now) global, pass that
// global variable to the callee. Otherwise use the caller's
// function parameter for this pair.
const ast::Variable* var =
IsGlobal(new_pair)
? global_combined_texture_samplers_[new_pair]
: function_combined_texture_samplers_[call->Stmt()->Function()]
[new_pair];
return ctx.dst->Expr(var->name->symbol);
};
for (auto pair : callee->TextureSamplerPairs()) {
if (!pair.second) {
continue;
}
// Global pairs used by the callee do not require a function
// parameter at the call site.
if (IsGlobal(pair)) {
continue;
}
args.Push(make_arg(pair.first, pair.second));
}
for (auto pair : callee->TextureSamplerPairs()) {
if (pair.second) {
continue;
}
// Global pairs used by the callee do not require a function
// parameter at the call site.
if (IsGlobal(pair)) {
continue;
}
// Texture-only pairs do not require a function parameter if they've been
// replaced by a real pair.
if (FindFullTextureSamplerPair(pair.first, callee)) {
continue;
}
args.Push(make_arg(pair.first, nullptr));
}
// Append all of the remaining non-texture and non-sampler
// parameters.
for (auto* arg : expr->args) {
if (!ctx.src->TypeOf(arg)
->UnwrapRef()
->IsAnyOf<core::type::Texture, core::type::Sampler>()) {
args.Push(ctx.Clone(arg));
}
}
return ctx.dst->Call(ctx.Clone(expr->target), args);
}
}
return nullptr;
});
ctx.Clone();
return resolver::Resolve(b);
}
};
CombineSamplers::CombineSamplers() = default;
CombineSamplers::~CombineSamplers() = default;
ast::transform::Transform::ApplyResult CombineSamplers::Apply(const Program& src,
const ast::transform::DataMap& inputs,
ast::transform::DataMap&) const {
auto* binding_info = inputs.Get<BindingInfo>();
if (!binding_info) {
ProgramBuilder b;
b.Diagnostics().add_error(diag::System::Transform,
"missing transform data for " + std::string(TypeInfo().name));
return resolver::Resolve(b);
}
return State(src, binding_info).Run();
}
} // namespace tint::glsl::writer