dolphin/Data/User/Shaders/invertedoutline.txt

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(5,5)*resolution.zw);

  ocol0 = c0 - c1;
}