in vec3 TexCoords;
out vec4 FragColor;

uniform samplerCube textureSource;
uniform vec2 ScaleU;

void main()
{
    vec3 sampleDir = normalize(TexCoords);
    vec3 right = normalize(cross(sampleDir, vec3(0.0, 1.0, 0.0)));
    vec3 up = normalize(cross(right, sampleDir));

    vec3 color = vec3(0.0);
    float total = 0.0;
    for (float x = -4.0; x <= 4.0; x += 1.0) {
        for (float y = -4.0; y <= 4.0; y += 1.0) {
            vec3 offset = right * ScaleU.x * x + up * ScaleU.y * y;
            color += texture(textureSource, normalize(sampleDir + offset)).rgb;
            total += 1.0;
        }
    }
    FragColor = vec4(color / total, 1.0);
}