#version 150 core in vec3 Color; out vec4 outColor; void main() { outColor = vec4(1.0 - Color.r, 1.0 - Color.g, 1.0 - Color.b, 1.0); // or outColor = vec4(1.0 - Color.x, 1.0 - Color.y, 1.0 - Color.z, 1.0); // or even outColor = vec4(1.0 - Color, 1.0); }