ShaderGen
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#.
Shaders 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).
Example Shader
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_;
}