#version 330 core out vec4 FragColor; in vec2 TexCoords; uniform sampler2D screenTexture; void main() { vec3 col = texture(screenTexture, TexCoords).rgb; float grayscale = 0.2126 * col.r + 0.7152 * col.g + 0.0722 * col.b; FragColor = vec4(vec3(grayscale), 1.0); }