// A simple, circular vignette, with a cosĀ² falloff. uniform float PREFIX(inv_radius); uniform vec2 PREFIX(aspect_correction); vec4 FUNCNAME(vec2 tc) { vec4 x = LAST_INPUT(tc); const float pihalf = 0.5 * 3.14159265358979324; vec2 normalized_pos = (tc - PREFIX(center)) * PREFIX(aspect_correction); float dist = (length(normalized_pos) - PREFIX(inner_radius)) * PREFIX(inv_radius); float linear_falloff = clamp(dist, 0.0, 1.0) * pihalf; float falloff = cos(linear_falloff) * cos(linear_falloff); x.rgb *= vec3(falloff); return x; }