example.metal

struct VertexArgBufferA {
    const device Uniforms *uniforms               [[ id(WKSUniformArgBuffer) ]];
    const device UniformDrawStateA *uniDrawState  [[ id(WKSUniformDrawStateArgBuffer) ]];
};

// Vertex shader for simple line on the globe
vertex ProjVertexA vertexLineOnly_globe(
    VertexA vert [[stage_in]],
    const device VertexArgBufferA & vertArgs [[buffer(WKSVertexArgBuffer)]])
{
    ProjVertexA outVert;
    
    outVert.color = float4(vert.color) * vertArgs.uniDrawState->fade;
    if (vertArgs.uniDrawState->clipCoords) {
        outVert.dotProd = 1.0;
        outVert.position = vertArgs.uniforms->mvpMatrix * float4(vert.position,1.0);
    } else {
        float4 pt = vertArgs.uniforms->mvMatrix * float4(vert.position, 1.0);
        pt /= pt.w;
        float4 testNorm = vertArgs.uniforms->mvNormalMatrix * float4(vert.normal,0.0);
        outVert.dotProd = dot(-pt.xyz,testNorm.xyz);
        outVert.position = vertArgs.uniforms->mvpMatrix * float4(vert.position,1.0);
    }
    
    return outVert;
}