dolphin/Data/User/Shaders/fire2.txt

uniform samplerRECT samp0 : register(s0);

void main(out float4 ocol0 : COLOR0, in float2 uv0 : TEXCOORD0)
{
  float4 c0 = texRECT(samp0, uv0).rgba;
  float red   = 0.0;
  float green = 0.0;
  float blue  = 0.0;
  float avg = (c0.r + c0.g + c0.b) / 3;

  red = c0.r + (c0.g / 2) + (c0.b / 3);
  green = c0.r / 3;
  
  ocol0 = float4(red, green, blue, 1.0);
}