| // Copyright 2013 The Flutter Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef FLUTTER_IMPELLER_RENDERER_SHADER_STAGE_COMPATIBILITY_CHECKER_H_ |
| #define FLUTTER_IMPELLER_RENDERER_SHADER_STAGE_COMPATIBILITY_CHECKER_H_ |
| |
| namespace impeller { |
| /// This is a classed use to check that the input slots of fragment shaders |
| /// match the output slots of the vertex shaders. |
| /// If they don't match it will result in linker errors when creating the |
| /// pipeline. It's not used at runtime. |
| template <typename VertexShaderT, typename FragmentShaderT> |
| class ShaderStageCompatibilityChecker { |
| public: |
| static constexpr bool CompileTimeStrEqual(const char* str1, |
| const char* str2) { |
| return *str1 == *str2 && |
| (*str1 == '\0' || CompileTimeStrEqual(str1 + 1, str2 + 1)); |
| } |
| |
| /// Returns `true` if the shader input slots for the fragment shader match the |
| /// ones declared as outputs in the vertex shader. |
| static constexpr bool Check() { |
| constexpr size_t num_outputs = VertexShaderT::kAllShaderStageOutputs.size(); |
| constexpr size_t num_inputs = FragmentShaderT::kAllShaderStageInputs.size(); |
| |
| if (num_inputs > num_outputs) { |
| return false; |
| } |
| |
| for (size_t i = 0; i < num_inputs; ++i) { |
| const ShaderStageIOSlot* input_slot = |
| FragmentShaderT::kAllShaderStageInputs[i]; |
| for (size_t j = 0; j < num_outputs; ++j) { |
| const ShaderStageIOSlot* output_slot = |
| VertexShaderT::kAllShaderStageOutputs[j]; |
| if (input_slot->location == output_slot->location) { |
| if (!CompileTimeStrEqual(input_slot->name, output_slot->name) || |
| input_slot->set != output_slot->set || |
| input_slot->binding != output_slot->binding || |
| input_slot->type != output_slot->type || |
| input_slot->bit_width != output_slot->bit_width || |
| input_slot->vec_size != output_slot->vec_size || |
| input_slot->columns != output_slot->columns || |
| input_slot->offset != output_slot->offset) { |
| return false; |
| } |
| } |
| } |
| } |
| |
| return true; |
| } |
| }; |
| |
| // The following shaders don't define output slots. |
| // TODO(https://github.com/flutter/flutter/issues/146852): Make impellerc emit |
| // an empty array for output slots. |
| struct CheckerboardVertexShader; |
| struct ClipVertexShader; |
| |
| template <typename FragmentShaderT> |
| class ShaderStageCompatibilityChecker<CheckerboardVertexShader, |
| FragmentShaderT> { |
| public: |
| static constexpr bool Check() { return true; } |
| }; |
| |
| template <typename FragmentShaderT> |
| class ShaderStageCompatibilityChecker<ClipVertexShader, FragmentShaderT> { |
| public: |
| static constexpr bool Check() { return true; } |
| }; |
| } // namespace impeller |
| #endif // FLUTTER_IMPELLER_RENDERER_SHADER_STAGE_COMPATIBILITY_CHECKER_H_ |