Weird shader compiler error

Question

I am trying to draw a full screen quad without a vertex buffer. SV_VertexID should do the trick, although I get a weird error in my shader on the following line:

PS_IN VS(uint VertexID : SV_VertexID)// << this is the line that causes trouble
{
    PS_IN output = (PS_IN)0;

    float4 pos = float4( (VertexID << 1) & 2, VertexID & 2 ,0,1);
    output.pos = mul(pos, wvp );

    float4 t = mul(pos, texTransform);
    output.tex = float2(t.x,t.y);

    return output;
}

The error message:

invalid type used for 'SV_VertexID' input semantics, must be integral

This is how I compile the shader:

fxc.exe /Tvs_4_0_level_9_3 /EVS /Fo Texture_VS.fxo Texture.fx

I dont understand why, as the type is integral. Why do I get this compiler error?

Answer 1

Do you do a #define uint float or similar anywhere?

That code compiled for me as vs_5_0 once I added appropriate definitions of PS_IN etc. Are you compiling it as a pixel shader or something?

http://msdn.microsoft.com/en-us/library/windows/desktop/bb509647%28v=vs.85%29.aspx

Other system values (SV_VertexID, SV_InstanceID, SV_IsFrontFace) can only be input into the first active shader in the pipeline that can interpret the particular value; after that the shader function must pass the values to subsequent stages.