ifsrenderer-linux / WpfDisplay / Library / PostEffects / ChromaticAberration.ifsfx

@Name: Chromatic Aberration
@Version: 1.0
@Description: Multi-level chromatic aberration effect.
@Reference: https://en.wikipedia.org/wiki/Chromatic_aberration

@Spread: 0.01
@Levels: 64
@CircleSize: 0.5
@CenterOffset: 0.0 0.0 0.0
@CircleFeather: 0.1

float mask = smoothstep(float(@CircleSize), float(@CircleSize) + float(@CircleFeather), length((uv + @CenterOffset.xy) - vec2(0.5)));
vec2 offset = ((uv - vec2(0.5)) + @CenterOffset.xy) * mask;

vec3 sum = vec3(0.0);
vec3 accumulated_rgb = vec3(0.0);
int loop_levels = int(@Levels);
for(int i = 0; i < loop_levels; i++){
    float t = 2.0 * float(i) / float(loop_levels - 1);
    vec3 slice = vec3(1.0 - t, 1.0 - abs(t - 1.0), t - 1.0);
    slice = max(slice, 0.0);
    sum += slice;
    vec2 slice_offset = (t - 1.0) * float(@Spread) * offset;
    accumulated_rgb += slice * texture(input_tex, uv + slice_offset).rgb;
}

if (sum.x > 0.0 && sum.y > 0.0 && sum.z > 0.0) {
    accumulated_rgb /= sum;
}

output_color = vec4(accumulated_rgb, input_color.a);