// laplace filter
float time=0.5;
float sampleDist = 1.0f/512.0f;  // distance one pixel in u/v

sampler2D image : register(s0);

static const float2 offsets[4] = {
	-1,  0,
	0,  1,
	1,  0,
	0, -1,
};

float4 main(
	float4 Pos : POSITION,
	float2 texCoord: TEXCOORD0) : COLOR 
{
	//float4 img = tex2D(image, texCoord);
	//return img;

	//  blur  (4 neigbours average)
	float4 sum = 0;
	float scale = 0.25;
	float offset=0;

	
	//laplace filter
	sum  = -4 * tex2D(image, texCoord);	
	scale = 4.0;
	offset = 0.5;

	for (int i = 0; i < 4; i++) {
		sum += tex2D(image, texCoord + sampleDist * offsets[i]);
	}

	sum = offset + sum * scale;	  
	return sum;
	//return lerp(sum,float4(1,1,1,1)-sum,time);	  //-sum
}