A proof-of-concept library which generates shader code from C#. Currently, the project can generate HLSL (D3D11), GLSL-330 (core-GL-compatible), GLSLES-300 (OpenGL ES-compatible), GLSL-450 (Vulkan-compatible), and Metal shader code from a single shader source specified in C#.
Writing shader code in C# could have quite a few benefits:
- Easily share type definitions between graphics code in C# and shaders.
- For example, one could re-use the same structure to describe the input to a vertex shader, as well as to store the actual vertex data in your C# program.
- Shader uniforms ("constant buffers") can be shared as well.
- Analysis done at code-generation time can be used to build extra metadata about the shaders, enabling reflection-like capabilities.
- The full vertex input specification can be generated when doing the C# analysis for code generation.
- The layouts and order for all global shader resources can be captured.
- Validation can be performed to ensure, for example, uniforms are multiples of 16-bytes in size, etc.
- C# refactoring tools can be used.
- C# niceties like inheritance, composition, partial declarations, etc. can be leveraged for easier shader writing (speculative).
Here is an example vertex and fragment shader, written in C# with ShaderGen:
public class MinExample { public Matrix4x4 Projection; public Matrix4x4 View; public Matrix4x4 World; public Texture2DResource SurfaceTexture; public SamplerResource Sampler; public struct VertexInput { [PositionSemantic] public Vector3 Position; [TextureCoordinateSemantic] public Vector2 TextureCoord; } public struct FragmentInput { [SystemPositionSemanticAttribute] public Vector4 Position; [TextureCoordinateSemantic] public Vector2 TextureCoord; } [VertexShader] public FragmentInput VertexShaderFunc(VertexInput input) { FragmentInput output; Vector4 worldPosition = Mul(World, new Vector4(input.Position, 1)); Vector4 viewPosition = Mul(View, worldPosition); output.Position = Mul(Projection, viewPosition); output.TextureCoord = input.TextureCoord; return output; } [FragmentShader] public Vector4 FragmentShaderFunc(FragmentInput input) { return Sample(SurfaceTexture, Sampler, input.TextureCoord); } }
Here is some representative output from the library (subject to change, etc.):
HLSL Vertex Shader
struct MinExample_VertexInput { float3 Position : POSITION0; float2 TextureCoord : TEXCOORD0; }; struct MinExample_FragmentInput { float4 Position : SV_Position; float2 TextureCoord : TEXCOORD0; }; cbuffer ProjectionBuffer : register(b0) { float4x4 Projection; } cbuffer ViewBuffer : register(b1) { float4x4 View; } cbuffer WorldBuffer : register(b2) { float4x4 World; } MinExample_FragmentInput VertexShaderFunc( MinExample_VertexInput input) { MinExample_FragmentInput output; float4 worldPosition = mul(World, float4(input.Position, 1)); float4 viewPosition = mul(View, worldPosition); output.Position = mul(Projection, viewPosition); output.TextureCoord = input.TextureCoord; return output; }
HLSL Fragment Shader
struct MinExample_VertexInput { float3 Position : POSITION0; float2 TextureCoord : TEXCOORD0; }; struct MinExample_FragmentInput { float4 Position : SV_Position; float2 TextureCoord : TEXCOORD0; }; Texture2D SurfaceTexture : register(t0); SamplerState Sampler : register(s0); float4 FragmentShaderFunc( MinExample_FragmentInput input) : SV_Target { return SurfaceTexture.Sample(Sampler, input.TextureCoord); }
GLSL (450) Vertex Shader
#version 450 #extension GL_ARB_separate_shader_objects : enable #extension GL_ARB_shading_language_420pack : enable struct MinExample_VertexInput { vec3 Position; vec2 TextureCoord; }; struct MinExample_FragmentInput { vec4 Position; vec2 TextureCoord; }; layout(set = 0, binding = 0) uniform Projection { mat4 field_Projection; }; layout(set = 0, binding = 1) uniform View { mat4 field_View; }; layout(set = 0, binding = 2) uniform World { mat4 field_World; }; layout(set = 0, binding = 3) uniform texture2D SurfaceTexture; layout(set = 0, binding = 4) uniform sampler Sampler; MinExample_FragmentInput VertexShaderFunc( MinExample_VertexInput input_) { MinExample_FragmentInput output_; vec4 worldPosition = field_World * vec4(input_.Position, 1); vec4 viewPosition = field_View * worldPosition; output_.Position = field_Projection * viewPosition; output_.TextureCoord = input_.TextureCoord; return output_; } layout(location = 0) in vec3 Position; layout(location = 1) in vec2 TextureCoord; layout(location = 0) out vec2 fsin_0; void main() { MinExample_VertexInput input_; input_.Position = Position; input_.TextureCoord = TextureCoord; MinExample_FragmentInput output_ = VertexShaderFunc(input_); fsin_0 = output_.TextureCoord; gl_Position = output_.Position; gl_Position.y = -gl_Position.y; // Correct for Vulkan clip coordinates }
GLSL (450) Fragment Shader
#version 450 #extension GL_ARB_separate_shader_objects : enable #extension GL_ARB_shading_language_420pack : enable struct MinExample_VertexInput { vec3 Position; vec2 TextureCoord; }; struct MinExample_FragmentInput { vec4 Position; vec2 TextureCoord; }; layout(set = 0, binding = 0) uniform Projection { mat4 field_Projection; }; layout(set = 0, binding = 1) uniform View { mat4 field_View; }; layout(set = 0, binding = 2) uniform World { mat4 field_World; }; layout(set = 0, binding = 3) uniform texture2D SurfaceTexture; layout(set = 0, binding = 4) uniform sampler Sampler; vec4 FragmentShaderFunc( MinExample_FragmentInput input_) { return texture(sampler2D(SurfaceTexture, Sampler), input_.TextureCoord); } layout(location = 0) in vec2 fsin_0; layout(location = 0) out vec4 _outputColor_; void main() { MinExample_FragmentInput input_; input_.Position = gl_FragCoord; input_.TextureCoord = fsin_0; vec4 output_ = FragmentShaderFunc(input_); _outputColor_ = output_; }