struct VertexOut
{
	float4 VertexPosition		:POSITION;
	float2 TexCoord				:TEXCOORD;
	float4 Position				:TEXCOORD2;
	float4 Color				:COLOR0;
};


/*
  Vertex program for displaying particle system with rectangle rendertexture 
*/
VertexOut VertexProgram( float4 Position :POSITION,
						float4 Texcoord: TEXCOORD,
						float4 Color:COLOR0,
						float3 BillboardSize: NORMAL,
						uniform float4x4 ModelViewProj	:state.matrix.mvp
						)									
{
	VertexOut Out;	
	
	Out.Color=Color;
	
	Out.VertexPosition=mul(ModelViewProj, Position);
	Out.TexCoord=Texcoord.xy;
	
	Out.Position=Out.VertexPosition;
	Out.Position.x=Texcoord.w;
	Out.Position.z=(Out.Position.z/Out.Position.w+1)/2;
	Out.Position.y=Out.Position.z-0.5*Out.Position.x;
	
	return Out;	
}

/*
  Fragment program for displaying particle system with rectangle rendertexture
*/
void FragmentProgram(	VertexOut	In,
						uniform sampler2D Texture,
						uniform sampler2D frontTexture,
						out float4 Color:COLOR
						)
{
	float d=tex2D(frontTexture,In.TexCoord).r;	
	float d2=1.0-d;
	
	float frontDepth;
	float backDepth;
	
	frontDepth=In.Position.y+d*In.Position.x;
	backDepth=In.Position.y+d2*In.Position.x;	
			
	if(d==1)
	{
		frontDepth=1;
		backDepth=0;
	}
	backDepth=1-backDepth;
	
	Color=float4(frontDepth,backDepth,0,tex2D(Texture,In.TexCoord).r*0.17*In.Color.a);	
	//Color=float4(frontDepth,backDepth,0,1-backDepth-frontDepth);	
}