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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_NUM_WORKGROUPS_FROM_UNIFORM_H_
#define SRC_TINT_TRANSFORM_NUM_WORKGROUPS_FROM_UNIFORM_H_
#include <optional>
#include "src/tint/sem/binding_point.h"
#include "src/tint/transform/transform.h"
// Forward declarations
namespace tint {
class CloneContext;
} // namespace tint
namespace tint::transform {
/// NumWorkgroupsFromUniform is a transform that implements the `num_workgroups`
/// builtin by loading it from a uniform buffer.
///
/// The generated uniform buffer will have the form:
/// ```
/// struct num_workgroups_struct {
/// num_workgroups : vec3<u32>;
/// };
///
/// @group(0) @binding(0)
/// var<uniform> num_workgroups_ubo : num_workgroups_struct;
/// ```
/// The binding group and number used for this uniform buffer is provided via
/// the `Config` transform input.
///
/// @note Depends on the following transforms to have been run first:
/// * CanonicalizeEntryPointIO
class NumWorkgroupsFromUniform final : public Castable<NumWorkgroupsFromUniform, Transform> {
public:
/// Constructor
NumWorkgroupsFromUniform();
/// Destructor
~NumWorkgroupsFromUniform() override;
/// Configuration options for the NumWorkgroupsFromUniform transform.
struct Config final : public Castable<Data, transform::Data> {
/// Constructor
/// @param ubo_bp the binding point to use for the generated uniform buffer. If ubo_bp
/// contains no value, a free binding point will be used to ensure the generated program is
/// valid. Specifically, binding 0 of the largest used group plus 1 is used if at least one
/// resource is bound, otherwise group 0 binding 0 is used.
explicit Config(std::optional<sem::BindingPoint> ubo_bp);
/// Copy constructor
Config(const Config&);
/// Destructor
~Config() override;
/// The binding point to use for the generated uniform buffer. If ubo_bp contains no value,
/// a free binding point will be used. Specifically, binding 0 of the largest used group
/// plus 1 is used if at least one resource is bound, otherwise group 0 binding 0 is used.
std::optional<sem::BindingPoint> ubo_binding;
};
/// @copydoc Transform::Apply
ApplyResult Apply(const Program* program,
const DataMap& inputs,
DataMap& outputs) const override;
};
} // namespace tint::transform
#endif // SRC_TINT_TRANSFORM_NUM_WORKGROUPS_FROM_UNIFORM_H_