The shader is precompiled into binary and loaded when the program is running, which can improve performance and save startup time.

1. Use google shaderc to precompile and load shader

1.1 Download code https://github.com/google/shaderc

insert image description here
The third_party file needs to put the dependent third party.
Because of the problem of computer access to google, shaderc-2023.4\utils\git-sync-depsthe third party cannot be downloaded automatically through the script. Manually download
https://codeload.github.com/KhronosGroup/SPIRV-Tools/zip/refs/tags/v2023. 3.rc1
https://codeload.github.com/KhronosGroup/SPIRV-Headers/zip/refs/tags/sdk-1.3.250.1
https://codeload.github.com/KhronosGroup/glslang/zip/refs/tags/ sdk-1.3.250.1
insert image description here

1.2 configuration

Use CMake (cmake-gui) to build shaderc, generate vs project
Don't forget to configure the third-party library directory
insert image description here

1.3 compile

VS compiles shaderc to get header files and libraries
insert image description here

All libraries are dynamic libraries of MDD

2. Introduce shaderc into the engine

2.1 Add header files and libraries to CmakeLists.txt

insert image description here

shaderc provides two ways to reference,

Use libshaderc_combined directly, which is a static library
用glslang, OSDependent, OGLCompiler,shaderc_util, SPIRV, HLSL, SPIRV-Tools, and SPIRV-Tools-opt.

2.2 Source code modification

It will judge whether there is a cache file, if not, generate a shader bin file, and load the bin file if there is one openGLShader.cpp.CompileOrGetOpenGLBinaries
insert image description here

shaderc::SpvCompilationResult module = compiler.CompileGlslToSpv(source_text, Utils::GLShaderStageToShaderC(stage), m_FilePath.c_str(), options);

CreateProgramThe shader will be created according to the bin file, skipping the compilation process.

glShaderBinary(1, &shaderID, GL_SHADER_BINARY_FORMAT_SPIR_V, spirv.data(), spirv.size() * sizeof(uint32_t));
glSpecializeShader(shaderID, "main", 0, nullptr, nullptr);
glAttachShader(program, shaderID);

insert image description here

3. Performance

The way to directly compile the shader code, each shader consumes 20ms
The first time the shader is compiled to generate the bin file, each shader consumes 2000ms
The way to directly load the shader bin file, each shader consumes 5ms

Shader precompilation of self-made game engine