struct VS_OUT
{
	float4 hPosition	: POSITION;
	float4 cPosition	: TEXCOORD1;
	float2 texCoord		: TEXCOORD0;
	float r				: TEXCOORD2;	
	float4 center		: TEXCOORD3;
	float4 Color		: TEXCOORD4;
};

VS_OUT HPS_Smoke_S_VS (float4 position : POSITION,	
		float4 texCoord : TEXCOORD0,
		float4 Color: COLOR0,
		uniform float4x4 worldView,
		uniform float4x4 Proj,
		uniform float4x4 worldViewProj)
{
	VS_OUT OUT;
  
	float2 offset = texCoord.zw;
	float4 cPosition;   
	cPosition = mul(worldView, position);
	OUT.center = cPosition;	
	cPosition.xy += offset;				
	OUT.cPosition = cPosition;
	OUT.r = abs(texCoord.z);		
 
    OUT.hPosition = mul( Proj, cPosition );
     
    OUT.texCoord = texCoord.xy;
    OUT.Color = Color;    
	return OUT;
} 


float4 HPS_Smoke_S_PS(VS_OUT IN,
						uniform float4x4 Proj,
						uniform sampler2D Texture	) : COLOR
{
	float4 Color = 0;
	float f = 0;
	float b = 1;
	float alpha = 0;
		
	float d = length( IN.cPosition.xy- IN.center.xy);
	
	if( d < IN.r )
	{	 
	 float w = sqrt( IN.r * IN.r - d * d );
	 float4 fPosition = IN.cPosition;
	 float4 bPosition = IN.cPosition;
	 fPosition.z -= w;
	 bPosition.z += w;
	 fPosition = mul(Proj, fPosition);
	 bPosition = mul(Proj, bPosition);
	 f = fPosition.z / fPosition.w;
	 b = bPosition.z / bPosition.w;
	 
	// alpha = pow(w / IN.r, 4);		
	}
	else
	 discard;
	
	Color.r = b;
	Color.g = 1 - f;
	
	alpha = 1;
	Color.a = alpha * IN.Color.a;
	Color.a *= tex2D(Texture, IN.texCoord).r * 0.7;
	
	
	return Color; 
}