precision mediump float; uniform sampler2D Texture; uniform vec2 samplesOffset[4]; varying vec2 texCoord; void main() { vec3 color = vec3(0, 0, 0); for (int i = 0; i < 4; ++i) { color += texture2D(Texture, texCoord + samplesOffset[i]).rgb; } color /= 4; gl_FragColor = vec4(texture2D(Texture, texCoord ), 1.0); }