Hello everybody !
Is there any solution to make quadtone images ?
I see the Matchbox crok_2color.glsl or Duotone.mx but not quadtone.
Here is the GLSL 2 Color matchbox :
uniform sampler2D source;
uniform float Amount, Exposure;
uniform float dark_low, dark_high, light_low, light_high;
uniform float adsk_result_w, adsk_result_h;
uniform float brightness, contrast, saturation;
uniform vec3 light_tint, dark_tint;
vec2 resolution = vec2(adsk_result_w, adsk_result_h);
const vec3 lumc = vec3(0.2125, 0.7154, 0.0721);
void main(void)
{
vec2 uv = gl_FragCoord.xy / resolution.xy;
vec3 original = texture2D(source, uv).rgb;
vec3 col = original;
float bri = (col.x+col.y+col.z)/3.0;
float v = smoothstep(dark_low, dark_high, bri);
col = mix(dark_tint * bri, col, v);
v = smoothstep(light_low, light_high, bri);
col = mix(col, min(light_tint * col, 1.0), v);
col = mix(original, col, Amount);
vec3 avg_lum = vec3(0.5, 0.5, 0.5);
vec3 intensity = vec3(dot(col.rgb, lumc));
vec3 sat_color = mix(intensity, col.rgb, saturation);
vec3 con_color = mix(avg_lum, sat_color, contrast);
vec3 fin_col = con_color - 1.0 + brightness;
gl_FragColor = vec4(fin_col, 1.0) * Exposure;
}
Maybe it’s not too complicated to do it with 4 colors…
If anyone has a tip to reproduce it in Flame 
Thank you
Shiver
