struct VS_OUTPUT
{
    float4 vPosition : POSITION;
};

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

VS_OUTPUT main(uint vertexID : SV_VertexID)
{
    VS_OUTPUT output;
    output.vPosition = float4(vertices[vertexID], 0.0, 1.0);
    return output;
}