struct VS_OUT
{
	float4 hPosition : POSITION;
	float4 cPosition : TEXCOORD0;
	float  radius	 : TEXCOORD2;
	float4 texCoord	 : TEXCOORD1;
};

VS_OUT VP(float4 mPosition : POSITION,
		  uniform float4x4 worldView,
		  uniform float4x4 Proj,
		  uniform float4x4 worldViewProj
		  float2 texCoord :TEXCOORD0)
{
 VS_OUT Out;
 Out.texCoord.xy = texCoord; 
 Out.texCoord.zw = (texCoord * 2.0) - 1.0; 
 
 float2 offset = texCoord.zw;
 float4 cPosition = mul(worldView, mPosition);
 cPosition.xy += offset;
   
 Out.hPosition = mul( Proj, cPosition );
 Out.cPosition = cPosition;
 Out.radius = abs(offset.x);
 
  return OUT;
}

float4 FP(VS_OUT In,
		  uniform float4x4 Proj,
		  uniform sampler2D Texture):COLOR
{
	float4 color = 1;
	float front = 0;
	float back = 1;
	
	float4 tex = tex2D(Texture, In.texCoord.xy);
	float d = length(In.TexCoord.zw);
	float w = sqrt(In.radius * In.radius - d * d);
	if(d < r)
	{
		float4 positionF; float4 positionB;
		positionF = positionB = In.cPosition;
		positionF.z -= w;
		positionB.z += w;
		positionF = mul(Proj, positionF);
		positionB = mul(Proj, positionB);
		positionF = (positionF / positionF.w + 1.0) / 2.0;
		positionB = (positionB / positionB.w + 1.0) / 2.0;
	}
	color.rgb = positionF.z;
	
	return color;
}