// phong_preLighting_vertex.cg
//
// NOTE: This file cannot be directly compiled through CG... 
// it first must be parsed to insert channel-specific 
// instructions.
//

// OUTPUT data from this vertex program
//
struct vert2frag
{
    float4 hPosition            : POSITION;
    float4 wPosition            : TEXCOORD0;
	float4 ambientTexUv			: TEXCOORD2;
	float3 wNormal				: TEXCOORD1;

#if defined(COLOR_PER_VERTEX_AMBIENT)
	// Optional color per vertex
	float4	colorPerVertex		: COLOR0;

	#if defined(COLOR_PER_VERTEX_MASK)
		// Optional color per vertex mask, mapped to
		// user attribute 0
		float colorPerVertexMask;
	#endif	
#endif // COLOR_PER_VERTEX_AMBIENT	
};

// INPUT data for this vertex program
//
struct app2vert
{
    float4 position             : POSITION;
    float4 normal               : NORMAL;
	float4 ambientTexUv			: TEXCOORD0;

#if defined(COLOR_PER_VERTEX_AMBIENT)
	float4	colorPerVertex		: COLOR0;

	#if defined(COLOR_PER_VERTEX_MASK)
		// Optional color per vertex mask, mapped to
		// user attribute 0
		float colorPerVertexMask;
	#endif	
#endif // COLOR_PER_VERTEX_AMBIENT
};

vert2frag main(app2vert IN, 
               uniform float4x4 modelViewProj,				
               uniform float4x4 objToWorldMatrix,
			   uniform float4x4 objToWorldMatrix_invtrans)
{
    vert2frag OUT;

    modelViewProj = glstate.matrix.mvp;

    // Compute the clip-space vertex position.
    //
    OUT.hPosition = mul(modelViewProj, IN.position);

    // Compute the world-space vertex position.
    //
    OUT.wPosition = mul(objToWorldMatrix, IN.position);

    // Copy the texture coordinates.
    //
    OUT.ambientTexUv = IN.ambientTexUv;

    // Compute the geometric normal, expressed in world space.
	// Note: we pass in the tangent and binormal vector
	// rather than the normal. Then in the fragment program,
	// we recompute the normal using a cross-product. This ensures
	// that we'll get the correct normal even when the model matrix
	// has non-proportional scale, and it's cheaper than multiplying
	// by the inverse-transpose.
    //
	float4 oNormal = float4(normalize(IN.normal.xyz), 0);
	OUT.wNormal = mul(objToWorldMatrix_invtrans, oNormal).xyz;

#ifdef COLOR_PER_VERTEX_AMBIENT

	#if defined(COLOR_PER_VERTEX_MASK)
	
		#if defined(COLOR_PER_VERTEX_OPERATOR_modulate) || defined(COLOR_PER_VERTEX_OPERATOR_divide) || defined(COLOR_PER_VERTEX_OPERATOR_modulate2x)
			// Change mask to 1, and pass over white for modulation.
			if (IN.colorPerVertexMask < 0.5)
			{
				OUT.colorPerVertexMask = 1.0;
				OUT.colorPerVertex = float4(1.0, 1.0, 1.0, 1.0);
			}
			else
			{
				// Pass-through color-per-vertex.
				OUT.colorPerVertexMask = IN.colorPerVertexMask;
				OUT.colorPerVertex = float4(IN.colorPerVertex.rgba);
			}
		#else
			// Pass-through color-per-vertex.
			OUT.colorPerVertexMask = IN.colorPerVertexMask;
			OUT.colorPerVertex = float4(IN.colorPerVertex.rgba);
		#endif
	
	#else
		// Pass-through color-per-vertex.
		OUT.colorPerVertex = float4(IN.colorPerVertex.rgba);
	#endif	
#endif // COLOR_PER_VERTEX_AMBIENT

    return OUT;
}