Shaders

A game's own shaders are compiled to SPIR-V when the game builds, so the Vulkan renderer never compiles a shader while the game runs. BSGameLib.Game brings the compiler, bsshaderc, and the build step; nothing else needs installing.

Shaders compiled at build

Write shaders in GLSL the way the engine's own are written, for OpenGL, with .vert and .frag extensions, and list them in the project file:

<ItemGroup>
  <EmbeddedResource Include="Shaders\*" />
  <BSGameLibShader Include="Shaders\*.vert;Shaders\*.frag" />
</ItemGroup>

The EmbeddedResource line embeds the GLSL itself, which the OpenGL renderer uses. The BSGameLibShader line prepares each shader for Vulkan exactly as the engine would at runtime, compiles it, and embeds the SPIR-V where the Vulkan renderer looks for it. The stage comes from the extension.

Shaders already written for Vulkan go in BSGameLibRawShader items instead. They are compiled as they are and embedded as <RootNamespace>.Shaders.<Name><Vert|Frag>.spv, for code that loads SPIR-V by name.

The compiler runs on the machine doing the build, so building for another platform works.

Shaders the build never saw

A shader that only exists at runtime (read from a file, downloaded, or generated) has no precompiled SPIR-V. Without a runtime compiler the Vulkan renderer reports it once and draws without it. To compile such shaders, add BSGameLib.Game.ShaderCompiler:

dotnet add package BSGameLib.Game.ShaderCompiler --prerelease

using BSGameLib.Game.ShaderCompiler;
using Microsoft.Extensions.DependencyInjection;

protected override void Configure(IServiceCollection services) =>
  services.AddShaderCompiler();

Compiled shaders are cached on disk, by default in BSGameLib/ShaderCache under the local application data folder, shared between games; AddShaderCompiler(options => ...) sets CacheDirectory, or turns the cache off with UseDiskCache. It is a separate package because it carries shaderc's native library, which a game does not need when every shader is compiled at build.

The materials, lighting and full-screen effects that use these shaders are in Materials, effects and lighting.