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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.
#ifndef SRC_TINT_TRANSFORM_CANONICALIZE_ENTRY_POINT_IO_H_
#define SRC_TINT_TRANSFORM_CANONICALIZE_ENTRY_POINT_IO_H_
#include "src/tint/transform/transform.h"
namespace tint::transform {
/// CanonicalizeEntryPointIO is a transform used to rewrite shader entry point
/// interfaces into a form that the generators can handle. Each entry point
/// function is stripped of all shader IO attributes and wrapped in a function
/// that provides the shader interface.
/// The transform config determines whether to use global variables, structures,
/// or parameters for the shader inputs and outputs, and optionally adds
/// additional builtins to the shader interface.
///
/// Before:
/// ```
/// struct Locations{
/// @location(1) loc1 : f32;
/// @location(2) loc2 : vec4<u32>;
/// };
///
/// @fragment
/// fn frag_main(@builtin(position) coord : vec4<f32>,
/// locations : Locations) -> @location(0) f32 {
/// if (coord.w > 1.0) {
/// return 0.0;
/// }
/// var col : f32 = (coord.x * locations.loc1);
/// return col;
/// }
/// ```
///
/// After (using structures for all parameters):
/// ```
/// struct Locations{
/// loc1 : f32;
/// loc2 : vec4<u32>;
/// };
///
/// struct frag_main_in {
/// @builtin(position) coord : vec4<f32>;
/// @location(1) loc1 : f32;
/// @location(2) loc2 : vec4<u32>
/// };
///
/// struct frag_main_out {
/// @location(0) loc0 : f32;
/// };
///
/// fn frag_main_inner(coord : vec4<f32>,
/// locations : Locations) -> f32 {
/// if (coord.w > 1.0) {
/// return 0.0;
/// }
/// var col : f32 = (coord.x * locations.loc1);
/// return col;
/// }
///
/// @fragment
/// fn frag_main(in : frag_main_in) -> frag_main_out {
/// let inner_retval = frag_main_inner(in.coord, Locations(in.loc1, in.loc2));
/// var wrapper_result : frag_main_out;
/// wrapper_result.loc0 = inner_retval;
/// return wrapper_result;
/// }
/// ```
///
/// @note Depends on the following transforms to have been run first:
/// * Unshadow
class CanonicalizeEntryPointIO final : public Castable<CanonicalizeEntryPointIO, Transform> {
public:
/// ShaderStyle is an enumerator of different ways to emit shader IO.
enum class ShaderStyle {
/// Target SPIR-V (using global variables).
kSpirv,
/// Target GLSL (using global variables).
kGlsl,
/// Target MSL (using non-struct function parameters for builtins).
kMsl,
/// Target HLSL (using structures for all IO).
kHlsl,
};
/// Configuration options for the transform.
struct Config final : public Castable<Config, Data> {
/// Constructor
/// @param style the approach to use for emitting shader IO.
/// @param sample_mask an optional sample mask to combine with shader masks
/// @param emit_vertex_point_size `true` to generate a pointsize builtin
explicit Config(ShaderStyle style,
uint32_t sample_mask = 0xFFFFFFFF,
bool emit_vertex_point_size = false);
/// Copy constructor
Config(const Config&);
/// Destructor
~Config() override;
/// The approach to use for emitting shader IO.
const ShaderStyle shader_style;
/// A fixed sample mask to combine into masks produced by fragment shaders.
const uint32_t fixed_sample_mask;
/// Set to `true` to generate a pointsize builtin and have it set to 1.0
/// from all vertex shaders in the module.
const bool emit_vertex_point_size;
};
/// Constructor
CanonicalizeEntryPointIO();
~CanonicalizeEntryPointIO() override;
/// @copydoc Transform::Apply
ApplyResult Apply(const Program* program,
const DataMap& inputs,
DataMap& outputs) const override;
private:
struct State;
};
} // namespace tint::transform
#endif // SRC_TINT_TRANSFORM_CANONICALIZE_ENTRY_POINT_IO_H_