#version 450 layout(location = 0) in vec3 v_normal; layout(location = 0) out vec4 f_color; const vec3 LIGHT = vec3(0.0, 0.0, 1.0); void main() { float brightness = dot(normalize(v_normal), normalize(LIGHT)); vec3 dark_color = vec3(0.6, 0.0, 0.0); vec3 regular_color = vec3(1.0, 0.0, 0.0); f_color = vec4(mix(dark_color, regular_color, brightness), 1.0); }