uniform sampler2D samp9;

out vec4 ocol0;
in vec2 uv0;

uniform vec4 resolution;

void main()
{
  float4 c0 = texture(samp9, uv0);
  float4 c1 = texture(samp9, uv0 + float2(1,1)*resolution.zw);
  float4 c2 = texture(samp9, uv0 + float2(-1,-1)*resolution.zw);
  float red   = c0.r;
  float green = c0.g;
  float blue  = c0.b;
  float alpha = c0.a;
  
  red = c0.r - c1.b;
  blue = c0.b - c2.r + (c0.g - c0.r);

  ocol0 = float4(red, 0.0, blue, alpha);
}