The false color replacement happens in a fragment shader that is quite
simple. It requires two textures (the one you want to display and the
one you want to use to false colorization). Then you can do (in your
fragment shader):
uniform sampler2D texture;
uniform sampler1D color_lut;
void main()
{
vec2 uv = gl_TexCoord[0].xy;
vec4 color = texture2D(texture, uv);
gl_FragColor = texture1D(color_lut,color.a);
}
Nicolas