# HG changeset patch
# User John Tsiombikas <nuclear@member.fsf.org>
# Date 1397512777 -10800
# Node ID 252999cd1a3fe2d085c827fb0c689018d764d21c
# Parent  859ccadca671e71dbedf9e378d70774f9b175745
added reflection and refraction

diff -r 859ccadca671 -r 252999cd1a3f src/main.cc
--- a/src/main.cc	Mon Apr 14 18:35:37 2014 +0300
+++ b/src/main.cc	Tue Apr 15 00:59:37 2014 +0300
@@ -156,7 +156,9 @@
 
 	Box *box = new Box;
 	box->mtl.diffuse = Vector3(0.1, 0.4, 1.0);
-	box->mtl.roughness = 0.9;
+	box->mtl.specular = Vector3(0.3, 0.6, 1.0);
+	box->mtl.roughness = 0.2;
+	box->mtl.reflect = 0.8;
 	box->set_position(Vector3(0, -1.1, 0));
 	box->set_scaling(Vector3(4, 0.1, 4));
 	scene->add(box);
diff -r 859ccadca671 -r 252999cd1a3f src/raytrace.cc
--- a/src/raytrace.cc	Mon Apr 14 18:35:37 2014 +0300
+++ b/src/raytrace.cc	Tue Apr 15 00:59:37 2014 +0300
@@ -22,17 +22,23 @@
 
 Vector3 shade(const RayHit &hit, int iter)
 {
+	const Material &mtl = hit.obj->mtl;
+
 	Vector3 pos = hit.ray.origin + hit.ray.dir * hit.dist;
 	Vector3 norm = hit.obj->hit_normal(hit);
 	norm = normalize(transform(normal_matrix(hit.obj->get_matrix()), norm));
 	Vector3 vdir = -normalize(hit.ray.dir);
 
+	float ior = mtl.ior;
+
+	if(dot(norm, hit.ray.dir) > 0.0) {
+		norm = -norm;
+		ior = 1.0 / mtl.ior;
+	}
+
 	Vector3 color = scene->get_ambient();
 
-	const Vector3 &kd = hit.obj->mtl.diffuse;
-	const Vector3 &ks = hit.obj->mtl.specular;
-	float roughness = hit.obj->mtl.roughness;
-
+	// for each light, calculate local illumination
 	int num_lights = scene->get_light_count();
 	for(int i=0; i<num_lights; i++) {
 		const Light *lt = scene->get_light(i);
@@ -44,15 +50,29 @@
 			// if we can see the light, calculate and add its contribution
 			ldir.normalize();
 			float ndotl = positive(dot(norm, ldir));
-			Vector3 diffuse = kd * lcol * ndotl;
+			Vector3 diffuse = mtl.diffuse * lcol * ndotl;
 
 			Vector3 hdir = normalize(ldir + vdir);
 			float ndoth = positive(dot(norm, hdir));
-			Vector3 specular = ks * lcol * pow(ndoth, roughness * 128.0);
+			Vector3 specular = mtl.specular * lcol * pow(ndoth, mtl.roughness * 128.0);
 
-			color = color + lerp(specular, diffuse, roughness);
+			color = color + lerp(specular, diffuse, mtl.roughness);
 		}
 	}
 
+	if(mtl.reflect > 1e-4 && iter < 6) {
+		Ray reflray(pos, reflect(vdir, norm));
+
+		Vector3 rcol = ray_trace(reflray, iter + 1) * mtl.specular * mtl.reflect;
+		color = color + rcol;
+	}
+
+	if(mtl.refract > 1e-4 && iter < 6) {
+		Ray refrray(pos, refract(vdir, norm,  ior));
+
+		Vector3 rcol = ray_trace(refrray, iter + 1) * mtl.specular * mtl.refract;
+		color = color + rcol;
+	}
+
 	return color;
 }
diff -r 859ccadca671 -r 252999cd1a3f src/vmath.h
--- a/src/vmath.h	Mon Apr 14 18:35:37 2014 +0300
+++ b/src/vmath.h	Tue Apr 15 00:59:37 2014 +0300
@@ -97,6 +97,25 @@
 			a.z + (b.z - a.z) * t);
 }
 
+inline Vector3 reflect(const Vector3 &v, const Vector3 &n)
+{
+	float vdotn = dot(v, n);
+	return n * vdotn * 2.0 - v;
+}
+
+inline Vector3 refract(const Vector3 &v, const Vector3 &n, float ior)
+{
+	float cos_inc = dot(v, -n);
+	float radical = 1.0 + ior * ior * (cos_inc * cos_inc - 1.0);
+
+	if(radical < 0.0) {	// total internal reflection
+		return -reflect(v, n);
+	}
+
+	float beta = ior * cos_inc - sqrt(radical);
+	return v * ior + n * beta;
+}
+
 // ---- Vector4 ----
 
 class Vector4 {