gh-3780.slang

//TEST:SIMPLE(filecheck=CHECK): -target spirv -emit-spirv-directly -skip-spirv-validation

// CHECK: OpEntryPoint

const static float2 positions[3] = {
  float2(0.0, -0.5),
  float2(0.5, 0.5),
  float2(-0.5, 0.5)
};

const static float3 colors[3] = {
  float3(1.0, 1.0, 0.0),
  float3(0.0, 1.0, 1.0),
  float3(1.0, 0.0, 1.0)
};

struct Vertex
{
    float4 pos : SV_Position;
    float3 color;
};

const static uint MAX_VERTS = 3;
const static uint MAX_PRIMS = 1;

[outputtopology("triangle")]
[numthreads(3, 1, 1)]
[shader("mesh")]
void entry_mesh(
    in uint tig : SV_GroupIndex,
    out vertices Vertex verts[MAX_VERTS],
    out indices uint3 triangles[MAX_PRIMS])
{
    const uint numVertices = 3;
    const uint numPrimitives = 1;
    SetMeshOutputCounts(numVertices, numPrimitives);

    if(tig < numVertices) {
        verts[tig] = {float4(positions[tig], 0, 1), colors[tig]};
    }

    if(tig < numPrimitives) {
        triangles[tig] = uint3(0,1,2);
    }
}

struct FragmentOut
{
    [[vk::location(0)]] float3 color;
};

[shader("fragment")]
FragmentOut entry_fragment(in Vertex vertex)
{
    FragmentOut frag_out;
    frag_out.color = float3(1,1,1);
    return frag_out;
}