| // Copyright 2020 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_FIRST_INDEX_OFFSET_H_ |
| #define SRC_TINT_TRANSFORM_FIRST_INDEX_OFFSET_H_ |
| |
| #include "src/tint/transform/transform.h" |
| |
| namespace tint::transform { |
| |
| /// Adds firstVertex/Instance (injected via root constants) to |
| /// vertex/instance index builtins. |
| /// |
| /// This transform assumes that Name transform has been run before. |
| /// |
| /// Unlike other APIs, D3D always starts vertex and instance numbering at 0, |
| /// regardless of the firstVertex/Instance value specified. This transformer |
| /// adds the value of firstVertex/Instance to each builtin. This action is |
| /// performed by adding a new constant equal to original builtin + |
| /// firstVertex/Instance to each function that references one of these builtins. |
| /// |
| /// Note that D3D does not have any semantics for firstVertex/Instance. |
| /// Therefore, these values must by passed to the shader. |
| /// |
| /// Before: |
| /// ``` |
| /// @builtin(vertex_index) var<in> vert_idx : u32; |
| /// fn func() -> u32 { |
| /// return vert_idx; |
| /// } |
| /// ``` |
| /// |
| /// After: |
| /// ``` |
| /// struct TintFirstIndexOffsetData { |
| /// tint_first_vertex_index : u32; |
| /// tint_first_instance_index : u32; |
| /// }; |
| /// @builtin(vertex_index) var<in> tint_first_index_offset_vert_idx : u32; |
| /// @binding(N) @group(M) var<uniform> tint_first_index_data : |
| /// TintFirstIndexOffsetData; |
| /// fn func() -> u32 { |
| /// const vert_idx = (tint_first_index_offset_vert_idx + |
| /// tint_first_index_data.tint_first_vertex_index); |
| /// return vert_idx; |
| /// } |
| /// ``` |
| /// |
| class FirstIndexOffset final : public Castable<FirstIndexOffset, Transform> { |
| public: |
| /// BindingPoint is consumed by the FirstIndexOffset transform. |
| /// BindingPoint specifies the binding point of the first index uniform |
| /// buffer. |
| struct BindingPoint final : public Castable<BindingPoint, transform::Data> { |
| /// Constructor |
| BindingPoint(); |
| |
| /// Constructor |
| /// @param b the binding index |
| /// @param g the binding group |
| BindingPoint(uint32_t b, uint32_t g); |
| |
| /// Destructor |
| ~BindingPoint() override; |
| |
| /// `@binding()` for the first vertex / first instance uniform buffer |
| uint32_t binding = 0; |
| /// `@group()` for the first vertex / first instance uniform buffer |
| uint32_t group = 0; |
| }; |
| |
| /// Data is outputted by the FirstIndexOffset transform. |
| /// Data holds information about shader usage and constant buffer offsets. |
| struct Data final : public Castable<Data, transform::Data> { |
| /// Constructor |
| /// @param has_vtx_or_inst_index True if the shader uses vertex_index or |
| /// instance_index |
| explicit Data(bool has_vtx_or_inst_index); |
| |
| /// Copy constructor |
| Data(const Data&); |
| |
| /// Destructor |
| ~Data() override; |
| |
| /// True if the shader uses vertex_index |
| const bool has_vertex_or_instance_index; |
| }; |
| |
| /// Constructor |
| FirstIndexOffset(); |
| /// Destructor |
| ~FirstIndexOffset() 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; |
| |
| private: |
| uint32_t binding_ = 0; |
| uint32_t group_ = 0; |
| }; |
| |
| } // namespace tint::transform |
| |
| #endif // SRC_TINT_TRANSFORM_FIRST_INDEX_OFFSET_H_ |