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// Copyright 2022 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_CLAMP_FRAG_DEPTH_H_
#define SRC_TINT_TRANSFORM_CLAMP_FRAG_DEPTH_H_
#include "src/tint/transform/transform.h"
// Forward declarations
namespace tint {
class CloneContext;
} // namespace tint
namespace tint::transform {
/// Add clamping of the `@builtin(frag_depth)` output of fragment shaders using two push constants
/// provided by the outside environment. For example the following code:
///
/// ```
/// @fragment fn main() -> @builtin(frag_depth) f32 {
/// return 0.0;
/// }
/// ```
///
/// Is transformed to:
///
/// ```
/// enable chromium_experimental_push_constant;
///
/// struct FragDepthClampArgs {
/// min : f32,
/// max : f32,
/// }
///
/// var<push_constant> frag_depth_clamp_args : FragDepthClampArgs;
///
/// fn clamp_frag_depth(v : f32) -> f32 {
/// return clamp(v, frag_depth_clamp_args.min, frag_depth_clamp_args.max);
/// }
///
/// @fragment
/// fn main() -> @builtin(frag_depth) f32 {
/// return clamp_frag_depth(0.0);
/// }
/// ```
class ClampFragDepth final : public Castable<ClampFragDepth, Transform> {
public:
/// Constructor
ClampFragDepth();
/// Destructor
~ClampFragDepth() override;
/// @param program the program to inspect
/// @param data optional extra transform-specific input data
/// @returns true if this transform should be run for the given program
bool ShouldRun(const Program* program, const DataMap& data = {}) const override;
protected:
/// Runs the transform using the CloneContext built for transforming a
/// program. Run() is responsible for calling Clone() on the CloneContext.
/// @param ctx the CloneContext primed with the input program and
/// ProgramBuilder
/// @param inputs optional extra transform-specific input data
/// @param outputs optional extra transform-specific output data
void Run(CloneContext& ctx, const DataMap& inputs, DataMap& outputs) const override;
};
} // namespace tint::transform
#endif // SRC_TINT_TRANSFORM_CLAMP_FRAG_DEPTH_H_