shader OslCamera(
    matrix objectTransform = matrix(1,0,0,0,0,1,0,0,0,0,1,0,0,0,0,1),

    float objectSize   = 3.6,
    output point pos             = P,
    output vector dir            = I,
    output float tMax            = 1.0/0.0)



{
   point cubePos = 0;

    // left
    if( u <= 0.5  && v <= 0.5)
    {
        cubePos = point(-0.5, -0.5 + 2 * v, -0.5 + 2 * u);
    }
    // right
    else if(u >= 0.5  && v < 0.5)
    {
        cubePos = point(-0.5 + (u-0.5)*2, -0.5 + 2 * v, 0.5);
    }
    // top
    else if (u > 0.5 && v >= 0.5)
    {
        cubePos = point(-0.5 + (u-0.5)*2, 0.5, 0.5 - (v-0.5)*2);
    }
    else
    {
        tMax = 0;
    }

    matrix objScale = matrix(objectSize);
    matrix finalTrans = objectTransform * objScale;
    point worldPos = transform(finalTrans, cubePos);
    dir = worldPos - P;

}