// input
struct vtxin 
{
  float4 position: POSITION;
  float3 normal: NORMAL;
  float4 color: COLOR0;
  float4 texCoord: TEXCOORD0;
};

// vtx output
struct vtxout
{
  float4 position: POSITION; // eye space
  float4 texCoord: TEXCOORD0;    

  float4 color: COLOR0;  
  float4 worldPos: TEXCOORD1; // world position
  float3 normal: TEXCOORD2;
  float4 mypos: TEXCOORD3;
};


// fragment input
struct fragin
{
	float4 color: COLOR0;  
	float4 position: POSITION; // eye space
	float4 texCoord: TEXCOORD0;    

	float4 projPos: WPOS;
	float4 worldPos: TEXCOORD1; // world position
	float3 normal: TEXCOORD2;
	float4 mypos: TEXCOORD3;
};


struct pixel
{
  float4 col: COLOR0;
  float4 pos: COLOR1;
  float4 norm: COLOR2;
};

#pragma position_invariant vtx

vtxout vtx(vtxin IN, 
		   const uniform float4x4 ModelViewProj,
		   uniform float4x4 ModelView)
{
	vtxout OUT;

	OUT.color = IN.color;
	OUT.texCoord = IN.texCoord;

	//OUT.worldPos = mul(glstate.matrix.inverse.projection, OUT.position);
	OUT.worldPos = mul(ModelView, IN.position);
	// transform the vertex position into eye space
	OUT.position = mul(glstate.matrix.mvp, IN.position);

	OUT.normal = IN.normal;
	OUT.mypos = OUT.position;

	return OUT;
}


pixel fragtex(fragin IN, 
			  uniform sampler2D dirtTex,
			  uniform float maxDepth,
			  uniform sampler2D tex,
			  uniform float3 currentPos)
{
	pixel pix;

	float4 texColor = tex2D(tex, IN.texCoord.xy);

	// save color in first render target
	// hack: use combination of emmisive + diffuse (emmisive used as constant ambient term)
	pix.col = (glstate.material.emission + glstate.material.diffuse) * texColor; 
	
	// save world position in second render target
	pix.pos = IN.worldPos * maxDepth;
	// save world space normal in third rt
	pix.norm.xyz = IN.normal;

	// store projection coordinates with positions (used for ssao)
	pix.norm.w = IN.projPos.w;
	// write the depth
	pix.pos.w = IN.mypos.z / IN.mypos.w;

	// account for alpha blending
	if (pix.col.w < 0.5f)
		discard;

	// hack: squeeze some information about ambient into the texture
	//pix.col.w = glstate.material.emission.x;
	pix.col.w = length((currentPos - IN.worldPos) * maxDepth);

	return pix;
}


pixel frag(fragin IN, uniform float maxDepth, uniform float3 currentPos)
{
	pixel pix;

	// hack: use comination of emmisive + diffuse (emmisive used as constant ambient term)
	pix.col = glstate.material.diffuse + glstate.material.emission;
	pix.pos = IN.worldPos * maxDepth;

	pix.norm.xyz = IN.normal;
	
	// store projection coordinates with positions (used for ssao)
	pix.norm.w = IN.mypos.w;
	// the projected depth
	pix.pos.w = IN.mypos.z / IN.mypos.w;
	
	// hack: squeeze some information about the ambient term into the target
	//pix.col.w = glstate.material.emission.x;
	pix.col.w = length((currentPos - IN.worldPos) * maxDepth);

	return pix;
}