meshula

float D_GGX(float linearRoughness, float NoH, const vec3 h) {
    // Walter et al. 2007, "Microfacet Models for Refraction through Rough Surfaces"

    // In mediump, there are two problems computing 1.0 - NoH^2
    // 1) 1.0 - NoH^2 suffers floating point cancellation when NoH^2 is close to 1 (highlights)
    // 2) NoH doesn't have enough precision around 1.0
    // Both problem can be fixed by computing 1-NoH^2 in highp and providing NoH in highp as well

    // However, we can do better using Lagrange's identity:
    //      ||a x b||^2 = ||a||^2 ||b||^2 - (a . b)^2

meshula

#include "cinder/app/AppCocoaTouch.h"
#include "cinder/app/Renderer.h"
#include "cinder/Camera.h"
#include "cinder/CinderResources.h"
#include "cinder/ImageIo.h"
#include "cinder/gl/Texture.h"

#include <vector>
#include <map>
#include <list>