dolphin/Data/User/Shaders/firewater.txt

uniform samplerRECT samp0 : register(s0);

void main(out float4 ocol0 : COLOR0, in float2 uv0 : TEXCOORD0)
{
  float4 c0 = texRECT(samp0, uv0).rgba;
  float4 c1 = texRECT(samp0, uv0 + float2(1,1)).rgba;
  float4 c2 = texRECT(samp0, uv0 + float2(-1,-1)).rgba;
  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);
}