/* -*- mode: c++; c-basic-offset: 4; indent-tabs-mode: nil -*- */

float4 main(in float4 texcoord : TEXCOORD0,
            uniform sampler3D volume,
            uniform sampler1D tf) : COLOR
{
    float4 sample = tex3D(volume, texcoord.xyz);

    // sample the transfer function texture
    float4 color = tex1D(tf, sample.x);

    // single slice render, only flat shading, completely opaque.
    color.w = 1;

    return color;
}