Shaders

Zenith.NET compiles Slang entry points for the active GraphicsApi, then creates Shader objects from the resulting descriptions. Pipeline creation combines those shader objects with workload-specific state.

Compile from a File

Pass the active graphics API, the source file, and the entry-point name to ZenithCompiler.CompileFromFile:

ShaderDesc vertexDesc = ZenithCompiler.CompileFromFile(context.GraphicsApi, "Shaders/Basic.slang", "VSMain");

Shader vertexShader = context.CreateShader(vertexDesc);

The name argument identifies the Slang entry point. Compile each entry point required by the pipeline, then assign the resulting shaders to its description.

Compile from Source

Use CompileFromSource when the Slang source is already available as a string:

const string source = """
[shader("compute")]
[numthreads(8, 8, 1)]
void CSMain(uint3 dispatchThreadID : SV_DispatchThreadID)
{
}
""";

ShaderDesc computeDesc = ZenithCompiler.CompileFromSource(context.GraphicsApi, source, "CSMain");

Shader computeShader = context.CreateShader(computeDesc);

Provide additional lookup directories through searchPaths when the shader imports other source files:

ShaderDesc desc = ZenithCompiler.CompileFromFile(context.GraphicsApi, "Shaders/Lighting.slang", "PSMain", ["Shaders", "Shaders/Shared"]);

Create a Pipeline

Assign compiled shaders to the pipeline description that matches the workload:

ComputePipeline pipeline = context.CreateComputePipeline(new() { ComputeShader = computeShader });

Graphics pipelines use vertex and fragment shaders, while mesh shading pipelines use mesh and fragment shaders and may also use a task shader. For both pipeline types, the attachment formats and render state must match the render pass where the pipeline is used.

Use Thread-Group Size

Compute shader reflection stores the entry point's thread-group dimensions in ShaderDesc.ThreadGroupSize. Use those values when converting a workload size into dispatch groups:

ThreadGroupSize threadGroupSize = computeShader.Desc.ThreadGroupSize;

uint groupCountX = (width + threadGroupSize.X - 1) / threadGroupSize.X;
uint groupCountY = (height + threadGroupSize.Y - 1) / threadGroupSize.Y;

commandBuffer.SetPipeline(pipeline);
commandBuffer.Dispatch(groupCountX, groupCountY, 1);

Round each dimension up to a complete group and handle threads outside the workload in the shader.

Manage Shader Lifetime

Shader objects are required while creating a pipeline and can be disposed after pipeline creation returns. Keep the pipeline alive until every submitted command that uses it has completed.