bool isect_plane(in vec3 ro, in vec3 rd, in vec4 plane, out HitPoint hit);
bool isect_sphere(in vec3 ro, in vec3 rd, in vec3 pos, float rad, out HitPoint hit);
+/* schlick's approximation: [5.0, 1.0, R(0deg)] */
+float hack_fresnel(vec3 i, vec3 n, vec3 fresnel_val);
+
vec3 tex_chess(in vec3 col1, in vec3 col2, in vec2 spos);
-const Material mtl_sph = Material(vec3(1.0, 1.0, 1.0) * 0.1, vec3(1.0, 1.0, 1.0), 80.0, 0.8, 0.0, 1.0);
-const Material mtl_glass = Material(vec3(1.0, 1.0, 1.0) * 0.01, vec3(1.0, 1.0, 1.0), 80.0, 0.0, 0.99, 1.52);
-const Material mtl_air = Material(vec3(1.0, 1.0, 1.0) * 0.01, vec3(1.0, 1.0, 1.0), 80.0, 0.0, 0.99, 1.0);
-const Material mtl_floor = Material(vec3(0.5, 0.5, 0.5), vec3(0.0, 0.0, 0.0), 1.0, 0.0, 0.0, 1.0);
+#define GREY(x) vec3(x, x, x)
+
+const Material mtl_sph = Material(GREY(0.1), GREY(1.0), 80.0, 0.8, 0.0, 0.0);
+const Material mtl_glass = Material(GREY(0.0), GREY(0.99), 80.0, 0.99, 0.99, 1.52);
+const Material mtl_air = Material(GREY(0.0), GREY(0.99), 80.0, 0.99, 0.99, 1.0);
+const Material mtl_floor = Material(GREY(0.5), GREY(0.0), 1.0, 0.0, 0.0, 0.0);
const vec3 light_pos = vec3(-10, 50, 30);
float entering = step(0.0, dot(-stack[top].ray.dir, hit.norm));
vec3 norm = faceforward(hit.norm, stack[top].ray.dir, hit.norm);
+ float fr = hack_fresnel(-stack[top].ray.dir, norm, vec3(5.0, 4.0, 0.01));
+ // fr = 1 everywhere when ior < 0.5 to avoid affecting the metal sphere
+ fr = min(1.0, (1.0 - step(0.5, hit.mtl.ior)) + fr);
+
int op = stack[top].op++;
if(op == 0) {
// reflection
- float energy = stack[top].ray.energy * hit.mtl.refl;
+ float energy = stack[top].ray.energy * hit.mtl.refl * fr;
+ if(hit.mtl.refr > 1e-4) {
+ energy += fr * 0.01;
+ }
if(energy > 1e-4) {
int next = top + 1;
stack[next].op = 0;
}
} else if(op == 1) {
// refraction
- float energy = stack[top].ray.energy * hit.mtl.refr;
+ float energy = stack[top].ray.energy * hit.mtl.refr * (1.0 - fr);
if(energy > 1e-4) {
float next_ior = mix(stack[top - 1].ray.ior, hit.mtl.ior, entering);
float ior = stack[top].ray.ior / next_ior;
return true;
}
+/* schlick's approximation: [5.0, 1.0, R(0deg)] */
+float hack_fresnel(vec3 i, vec3 n, vec3 fresnel_val)
+{
+ return fresnel_val.z + pow(1.0 - dot(i, n), fresnel_val.x) * fresnel_val.y;
+}
+
vec3 tex_chess(in vec3 col1, in vec3 col2, in vec2 spos)
{
float foo = step(0.5, mod(spos.x * 8.0, 1.0)) * 2.0 - 1.0;