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// Copyright 2021 The Tint Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "src/transform/multiplanar_external_texture.h"
#include <string>
#include <vector>
#include "src/ast/function.h"
#include "src/program_builder.h"
#include "src/sem/call.h"
#include "src/sem/function.h"
#include "src/sem/variable.h"
TINT_INSTANTIATE_TYPEINFO(tint::transform::MultiplanarExternalTexture);
TINT_INSTANTIATE_TYPEINFO(
tint::transform::MultiplanarExternalTexture::NewBindingPoints);
namespace tint {
namespace transform {
namespace {
/// This struct stores symbols for new bindings created as a result of
/// transforming a texture_external instance.
struct NewBindingSymbols {
Symbol params;
Symbol plane_0;
Symbol plane_1;
};
} // namespace
/// State holds the current transform state
struct MultiplanarExternalTexture::State {
/// The clone context.
CloneContext& ctx;
/// ProgramBuilder for the context
ProgramBuilder& b;
/// Desination binding locations for the expanded texture_external provided as
/// input into the transform.
const NewBindingPoints* new_binding_points;
/// Symbol for the ExternalTextureParams struct
Symbol params_struct_sym;
/// Symbol for the textureLoadExternal function
Symbol texture_load_external_sym;
/// Symbol for the textureSampleExternal function
Symbol texture_sample_external_sym;
/// Storage for new bindings that have been created corresponding to an
/// original texture_external binding.
std::unordered_map<Symbol, NewBindingSymbols> new_binding_symbols;
/// Constructor
/// @param context the clone
/// @param newBindingPoints the input destination binding locations for the
/// expanded texture_external
State(CloneContext& context, const NewBindingPoints* newBindingPoints)
: ctx(context), b(*context.dst), new_binding_points(newBindingPoints) {}
/// Processes the module
void Process() {
auto& sem = ctx.src->Sem();
// For each texture_external binding, we replace it with a texture_2d<f32>
// binding and create two additional bindings (one texture_2d<f32> to
// represent the secondary plane and one uniform buffer for the
// ExternalTextureParams struct).
ctx.ReplaceAll([&](const ast::Variable* var) -> const ast::Variable* {
if (!::tint::Is<ast::ExternalTexture>(var->type)) {
return nullptr;
}
// If the decorations are empty, then this must be a texture_external
// passed as a function parameter. These variables are transformed
// elsewhere.
if (var->decorations.empty()) {
return nullptr;
}
// If we find a texture_external binding, we know we must emit the
// ExternalTextureParams struct.
if (!params_struct_sym.IsValid()) {
createExtTexParamsStruct();
}
// The binding points for the newly introduced bindings must have been
// provided to this transform. We fetch the new binding points by
// providing the original texture_external binding points into the
// passed map.
BindingPoint bp = {var->BindingPoint().group->value,
var->BindingPoint().binding->value};
BindingsMap::const_iterator it =
new_binding_points->bindings_map.find(bp);
if (it == new_binding_points->bindings_map.end()) {
b.Diagnostics().add_error(
diag::System::Transform,
"missing new binding points for texture_external at binding {" +
std::to_string(bp.group) + "," + std::to_string(bp.binding) +
"}");
return nullptr;
}
BindingPoints bps = it->second;
// Symbols for the newly created bindings must be saved so they can be
// passed as parameters later. These are placed in a map and keyed by
// the source symbol associated with the texture_external binding that
// corresponds with the new destination bindings.
// NewBindingSymbols new_binding_syms;
auto& syms = new_binding_symbols[var->symbol];
syms.plane_0 = ctx.Clone(var->symbol);
syms.plane_1 = b.Symbols().New("ext_tex_plane_1");
b.Global(syms.plane_1,
b.ty.sampled_texture(ast::TextureDimension::k2d, b.ty.f32()),
b.GroupAndBinding(bps.plane_1.group, bps.plane_1.binding));
syms.params = b.Symbols().New("ext_tex_params");
b.Global(syms.params, b.ty.type_name("ExternalTextureParams"),
ast::StorageClass::kUniform,
b.GroupAndBinding(bps.params.group, bps.params.binding));
// Replace the original texture_external binding with a texture_2d<f32>
// binding.
ast::DecorationList cloned_decorations = ctx.Clone(var->decorations);
const ast::Expression* cloned_constructor = ctx.Clone(var->constructor);
return b.Var(syms.plane_0,
b.ty.sampled_texture(ast::TextureDimension::k2d, b.ty.f32()),
cloned_constructor, cloned_decorations);
});
// Transform the original textureLoad and textureSampleLevel calls into
// textureLoadExternal and textureSampleExternal calls.
ctx.ReplaceAll(
[&](const ast::CallExpression* expr) -> const ast::CallExpression* {
auto* intrinsic = sem.Get(expr)->Target()->As<sem::Intrinsic>();
if (intrinsic && !intrinsic->Parameters().empty() &&
intrinsic->Parameters()[0]->Type()->Is<sem::ExternalTexture>() &&
intrinsic->Type() != sem::IntrinsicType::kTextureDimensions) {
auto it = new_binding_symbols.find(
expr->args[0]->As<ast::IdentifierExpression>()->symbol);
if (it == new_binding_symbols.end()) {
// If valid new binding locations were not provided earlier, we
// would have been unable to create these symbols. An error
// message was emitted earlier, so just return early to avoid
// internal compiler errors and retain a clean error message.
return nullptr;
}
auto& syms = it->second;
if (intrinsic->Type() == sem::IntrinsicType::kTextureLoad) {
return createTexLdExt(expr, syms);
}
if (intrinsic->Type() == sem::IntrinsicType::kTextureSampleLevel) {
return createTexSmpExt(expr, syms);
}
} else if (sem.Get(expr)->Target()->Is<sem::Function>()) {
// The call expression may be to a user-defined function that
// contains a texture_external parameter. These need to be expanded
// out to multiple plane textures and the texture parameters
// structure.
for (const ast::Expression* arg : expr->args) {
if (auto* id_expr = arg->As<ast::IdentifierExpression>()) {
// Check if a parameter is a texture_external by trying to find
// it in the transform state.
auto it = new_binding_symbols.find(id_expr->symbol);
if (it != new_binding_symbols.end()) {
auto& syms = it->second;
// When we find a texture_external, we must unpack it into its
// components.
ctx.Replace(id_expr, b.Expr(syms.plane_0));
ctx.InsertAfter(expr->args, id_expr, b.Expr(syms.plane_1));
ctx.InsertAfter(expr->args, id_expr, b.Expr(syms.params));
}
}
}
}
return nullptr;
});
// We must update all the texture_external parameters for user declared
// functions.
ctx.ReplaceAll([&](const ast::Function* fn) -> const ast::Function* {
for (const ast::Variable* param : fn->params) {
if (::tint::Is<ast::ExternalTexture>(param->type)) {
// If we find a texture_external, we must ensure the
// ExternalTextureParams struct exists.
if (!params_struct_sym.IsValid()) {
createExtTexParamsStruct();
}
// When a texture_external is found, we insert all components
// the texture_external into the parameter list. We must also place
// the new symbols into the transform state so they can be used when
// transforming function calls.
auto& syms = new_binding_symbols[param->symbol];
syms.plane_0 = ctx.Clone(param->symbol);
syms.plane_1 = b.Symbols().New("ext_tex_plane_1");
syms.params = b.Symbols().New("ext_tex_params");
auto tex2d_f32 = [&] {
return b.ty.sampled_texture(ast::TextureDimension::k2d, b.ty.f32());
};
ctx.Replace(param, b.Param(syms.plane_0, tex2d_f32()));
ctx.InsertAfter(fn->params, param,
b.Param(syms.plane_1, tex2d_f32()));
ctx.InsertAfter(
fn->params, param,
b.Param(syms.params, b.ty.type_name(params_struct_sym)));
}
}
// Clone the function. This will use the Replace() and InsertAfter() calls
// above.
return nullptr;
});
}
/// Creates the ExternalTextureParams struct.
void createExtTexParamsStruct() {
ast::StructMemberList member_list = {
b.Member("numPlanes", b.ty.u32()), b.Member("vr", b.ty.f32()),
b.Member("ug", b.ty.f32()), b.Member("vg", b.ty.f32()),
b.Member("ub", b.ty.f32())};
params_struct_sym = b.Symbols().New("ExternalTextureParams");
b.Structure(params_struct_sym, member_list,
ast::DecorationList{b.StructBlock()});
}
/// Constructs a StatementList containing all the statements making up the
/// bodies of the textureSampleExternal and textureLoadExternal functions.
/// @param callType determines which function body to generate
/// @returns a statement list that makes of the body of the chosen function
ast::StatementList createTexFnExtStatementList(sem::IntrinsicType callType) {
using f32 = ProgramBuilder::f32;
const ast::CallExpression* single_plane_call;
const ast::CallExpression* plane_0_call;
const ast::CallExpression* plane_1_call;
if (callType == sem::IntrinsicType::kTextureSampleLevel) {
// textureSampleLevel(plane0, smp, coord.xy, 0.0);
single_plane_call =
b.Call("textureSampleLevel", "plane0", "smp", "coord", 0.0f);
// textureSampleLevel(plane0, smp, coord.xy, 0.0);
plane_0_call =
b.Call("textureSampleLevel", "plane0", "smp", "coord", 0.0f);
// textureSampleLevel(plane1, smp, coord.xy, 0.0);
plane_1_call =
b.Call("textureSampleLevel", "plane1", "smp", "coord", 0.0f);
} else if (callType == sem::IntrinsicType::kTextureLoad) {
// textureLoad(plane0, coords.xy, 0);
single_plane_call = b.Call("textureLoad", "plane0", "coord", 0);
// textureLoad(plane0, coords.xy, 0);
plane_0_call = b.Call("textureLoad", "plane0", "coord", 0);
// textureLoad(plane1, coords.xy, 0);
plane_1_call = b.Call("textureLoad", "plane1", "coord", 0);
}
return {
// if (params.numPlanes == 1u) {
// return singlePlaneCall
// }
b.If(b.create<ast::BinaryExpression>(
ast::BinaryOp::kEqual, b.MemberAccessor("params", "numPlanes"),
b.Expr(1u)),
b.Block(b.Return(single_plane_call))),
// let y = plane0Call.r - 0.0625;
b.Decl(b.Const("y", nullptr,
b.Sub(b.MemberAccessor(plane_0_call, "r"), 0.0625f))),
// let uv = plane1Call.rg - 0.5;
b.Decl(b.Const("uv", nullptr,
b.Sub(b.MemberAccessor(plane_1_call, "rg"), 0.5f))),
// let u = uv.x;
b.Decl(b.Const("u", nullptr, b.MemberAccessor("uv", "x"))),
// let v = uv.y;
b.Decl(b.Const("v", nullptr, b.MemberAccessor("uv", "y"))),
// let r = 1.164 * y + params.vr * v;
b.Decl(b.Const("r", nullptr,
b.Add(b.Mul(1.164f, "y"),
b.Mul(b.MemberAccessor("params", "vr"), "v")))),
// let g = 1.164 * y - params.ug * u - params.vg * v;
b.Decl(
b.Const("g", nullptr,
b.Sub(b.Sub(b.Mul(1.164f, "y"),
b.Mul(b.MemberAccessor("params", "ug"), "u")),
b.Mul(b.MemberAccessor("params", "vg"), "v")))),
// let b = 1.164 * y + params.ub * u;
b.Decl(b.Const("b", nullptr,
b.Add(b.Mul(1.164f, "y"),
b.Mul(b.MemberAccessor("params", "ub"), "u")))),
// return vec4<f32>(r, g, b, 1.0);
b.Return(b.vec4<f32>("r", "g", "b", 1.0f)),
};
}
/// Creates the textureSampleExternal function if needed and returns a call
/// expression to it.
/// @param expr the call expression being transformed
/// @param syms the expanded symbols to be used in the new call
/// @returns a call expression to textureSampleExternal
const ast::CallExpression* createTexSmpExt(const ast::CallExpression* expr,
NewBindingSymbols syms) {
ast::ExpressionList params;
const ast::Expression* plane_0_binding_param = ctx.Clone(expr->args[0]);
if (expr->args.size() != 3) {
TINT_ICE(Transform, b.Diagnostics())
<< "expected textureSampleLevel call with a "
"texture_external to have 3 parameters, found "
<< expr->args.size() << " parameters";
}
if (!texture_sample_external_sym.IsValid()) {
texture_sample_external_sym = b.Symbols().New("textureSampleExternal");
// Emit the textureSampleExternal function.
ast::VariableList varList = {
b.Param("plane0",
b.ty.sampled_texture(ast::TextureDimension::k2d, b.ty.f32())),
b.Param("plane1",
b.ty.sampled_texture(ast::TextureDimension::k2d, b.ty.f32())),
b.Param("smp", b.ty.sampler(ast::SamplerKind::kSampler)),
b.Param("coord", b.ty.vec2(b.ty.f32())),
b.Param("params", b.ty.type_name(params_struct_sym))};
ast::StatementList statementList =
createTexFnExtStatementList(sem::IntrinsicType::kTextureSampleLevel);
b.Func(texture_sample_external_sym, varList, b.ty.vec4(b.ty.f32()),
statementList, {});
}
const ast::IdentifierExpression* exp = b.Expr(texture_sample_external_sym);
params = {plane_0_binding_param, b.Expr(syms.plane_1),
ctx.Clone(expr->args[1]), ctx.Clone(expr->args[2]),
b.Expr(syms.params)};
return b.Call(exp, params);
}
/// Creates the textureLoadExternal function if needed and returns a call
/// expression to it.
/// @param expr the call expression being transformed
/// @param syms the expanded symbols to be used in the new call
/// @returns a call expression to textureLoadExternal
const ast::CallExpression* createTexLdExt(const ast::CallExpression* expr,
NewBindingSymbols syms) {
ast::ExpressionList params;
const ast::Expression* plane_0_binding_param = ctx.Clone(expr->args[0]);
if (expr->args.size() != 2) {
TINT_ICE(Transform, b.Diagnostics())
<< "expected textureLoad call with a texture_external "
"to have 2 parameters, found "
<< expr->args.size() << " parameters";
}
if (!texture_load_external_sym.IsValid()) {
texture_load_external_sym = b.Symbols().New("textureLoadExternal");
// Emit the textureLoadExternal function.
ast::VariableList var_list = {
b.Param("plane0",
b.ty.sampled_texture(ast::TextureDimension::k2d, b.ty.f32())),
b.Param("plane1",
b.ty.sampled_texture(ast::TextureDimension::k2d, b.ty.f32())),
b.Param("coord", b.ty.vec2(b.ty.i32())),
b.Param("params", b.ty.type_name(params_struct_sym))};
ast::StatementList statement_list =
createTexFnExtStatementList(sem::IntrinsicType::kTextureLoad);
b.Func(texture_load_external_sym, var_list, b.ty.vec4(b.ty.f32()),
statement_list, {});
}
const ast::IdentifierExpression* exp = b.Expr(texture_load_external_sym);
params = {plane_0_binding_param, b.Expr(syms.plane_1),
ctx.Clone(expr->args[1]), b.Expr(syms.params)};
return b.Call(exp, params);
}
};
MultiplanarExternalTexture::NewBindingPoints::NewBindingPoints(
BindingsMap inputBindingsMap)
: bindings_map(std::move(inputBindingsMap)) {}
MultiplanarExternalTexture::NewBindingPoints::~NewBindingPoints() = default;
MultiplanarExternalTexture::MultiplanarExternalTexture() = default;
MultiplanarExternalTexture::~MultiplanarExternalTexture() = default;
// Within this transform, an instance of a texture_external binding is unpacked
// into two texture_2d<f32> bindings representing two possible planes of a
// single texture and a uniform buffer binding representing a struct of
// parameters. Calls to textureLoad or textureSampleLevel that contain a
// texture_external parameter will be transformed into a newly generated version
// of the function, which can perform the desired operation on a single RGBA
// plane or on seperate Y and UV planes.
void MultiplanarExternalTexture::Run(CloneContext& ctx,
const DataMap& inputs,
DataMap&) {
auto* new_binding_points = inputs.Get<NewBindingPoints>();
if (!new_binding_points) {
ctx.dst->Diagnostics().add_error(
diag::System::Transform,
"missing new binding point data for " + std::string(TypeInfo().name));
return;
}
State state(ctx, new_binding_points);
state.Process();
ctx.Clone();
}
} // namespace transform
} // namespace tint