This is a sample of using Metal Shading Language in Unity Shaders.

##Prerequisites

Unity: 2019

Pretty much like GLSL snippets, Metal snippets should be surrounded with METALPROGRAM/ENDMETAL. Please note that you specify entry points for vertex program and fragment shader like for "normal" unity shaders:

#pragma vertex vert
#pragma fragment frag

To connect your shaders with Unity you need to mark vertex inputs, uniforms and textures. Please note that for uniforms only one (shared between vertex program and fragment shaders) uniform buffer is supported.

Use METAL_VERTEX_INPUT to mark vertex data. Arguments are: 0 for position, 1 - normal, 2 - tangent, 3 - color, 4-7 - uvs

struct InputVP
{
	float4 pos METAL_VERTEX_INPUT(0);
	float2 uv  METAL_VERTEX_INPUT(3);
};

Use METAL_TEX_INPUT to mark used textures. Arguments are: first is metal type to use, second is the bind point and third is the property name.

METAL_TEX_INPUT(texture2d<half, access::sample>, 0, _MainTex)

Use METAL_BUFFER_INPUT to mark used buffers. HLSL analogue is StructuredBuffer, but unlike HLSL you need to pass element count yourself. Arguments are: first is the type of element, second is the bind point and third is the property name.

METAL_BUFFER_INPUT(ColorInput, 1, _ColorBuffer)

As metal do not have implicit UAV counters, unity is forced to allocate extra space in all Compute Buffers, so you also need METAL_BUFFER_INPUT_DATA to extract data pointer. Arguments are: first is the type of element, second is the property name.

METAL_BUFFER_INPUT_DATA(ColorInput, _ColorBuffer)

Use METAL_CONST_MATRIX and METAL_CONST_VECTOR to mark uniform declarations. Arguments are: METAL_CONST_VECTOR(type, dim, name) and METAL_CONST_MATRIX(type, rows, cols, name)

struct Globals
{
	METAL_CONST_MATRIX(float, 4,4, unity_ObjectToWorld);
	METAL_CONST_MATRIX(float, 4,4, unity_MatrixVP);
	METAL_CONST_VECTOR(half, 4, _Color);
};