uniform extern texture ScreenTexture;

float diamondMatrix[5][5] =	{
							{ 0.2, 0.4, 0.5, 0.4, 0.2},
							{ 0.4, 0.6, 0.8, 0.6, 0.4},
							{ 0.5, 0.8, 0.9, 0.8, 0.5},
							{ 0.4, 0.6, 0.8, 0.6, 0.4},
							{ 0.2, 0.4, 0.5, 0.4, 0.2}
							};

float xPixelWidth = (float)1 / (float)1280;
float yPixelWidth = (float)1 / (float)720;
//bool isBlack = false;

sampler ScreenS = sampler_state
{
	Texture = <ScreenTexture>;
};

int edgeWidth; // Set to 2, 1, or 0. 3 crashes Shader Model 2.

//XNA3.0 float4 PixelShader(float2 texCoord: TEXCOORD0) : COLOR
float4 GreyScale(float2 texCoord: TEXCOORD0) : COLOR
{
	float4 color = tex2D(ScreenS, texCoord);
	float grey = (color.r * 0.2126 + color.g * 0.7152 + color.b * 0.0722);
	color.r = grey;
	color.g = grey;
	color.b = grey;

	return color;
}

float4 PixelShaderFunction(float2 texCoord: TEXCOORD0) : COLOR
{
	/*
	float4 color = tex2D(ScreenS, texCoord);

	if (texCoord[0] > 0.5f)
	{
		color[0] = 1 - color[0];
		color[1] = 1 - color[1];
		color[2] = 1 - color[2];
	}
	*/

	int xPixelPos = (texCoord.x / xPixelWidth) % 5;
	int yPixelPos = (texCoord.y / yPixelWidth) % 5;


	float4 color = tex2D(ScreenS, texCoord);

	float intensity = color[0];
	//float intensity = 0.5;
	/*
	//Draw a 1px border around anything totally transparent
	float4 edgeColor;
	float2 coord;

	for(int i = -1; i <= 1; i++)
	{
		for(int j = -1; j <= 1; j++)
		{
			coord = texCoord;
			coord[0] += i * xPixelWidth;
			coord[1] += j * yPixelWidth;

			edgeColor = tex2D(ScreenS, coord);

			if(edgeColor[1] == 1)
			{
				color[0] = 0;
				color[1] = 0;
				color[2] = 0;
			}
		}
	}*/

	if(intensity < diamondMatrix[xPixelPos][yPixelPos])
	{
		return float4(0, 0, 0, color[3]);
	}
	else
	{
		return float4(1, 1, 1, color[3]);
	}
}
technique
{
	pass P0
	{
		//XNA3.0 PixelShader = compile ps_2_0 PixelShader();
		PixelShader = compile ps_2_0 GreyScale();
	}
	pass P1
	{
		PixelShader = compile ps_2_0 PixelShaderFunction();
	}
}