#version 450 // These come in from the previous shader (vertex) layout(location = 0) in vec4 out_color; // This goes out to the bound image in window_size_dependent setup layout(location = 0) out vec4 f_color; void main() { if (int(out_color.w) % 2 == 0) { f_color = out_color; f_color.w = 255.0; } }