# HG changeset patch
# User John Tsiombikas <nuclear@member.fsf.org>
# Date 1402054780 -10800
# Node ID 4a0a288ffb278110448f652591ad131f0f692ace
# Parent  0ced900e15a76a57c3afb4d40b5427b1c18fed2e
phong/lafortune BRDF

diff -r 0ced900e15a7 -r 4a0a288ffb27 liberebus/src/brdf.cc
--- a/liberebus/src/brdf.cc	Mon Jun 02 00:53:01 2014 +0300
+++ b/liberebus/src/brdf.cc	Fri Jun 06 14:39:40 2014 +0300
@@ -130,3 +130,45 @@
 {
 	return 1.0f;
 }
+
+// --- class PhongRefl ---
+PhongRefl::PhongRefl()
+{
+	shininess = 42.0;
+}
+
+Vector3 PhongRefl::sample_dir(const Vector3 &norm, const Vector3 &outdir) const
+{
+	// construct orthonormal basis with k being the reflection dir
+	Vector3 refl = outdir.reflection(norm).normalized();
+	Vector3 up = Vector3(0, 0, 1);
+	if(fabs(dot_product(refl, up)) - 1.0 < 0.001) {
+		up = Vector3(0, 1, 0);
+	}
+	Vector3 right = cross_product(up, refl);
+	up = cross_product(refl, right);
+
+	// construct the matrix transposed to move the sample from reflection
+	// space to world space
+	Matrix3x3 xform;
+	xform.set_column_vector(right, 0);
+	xform.set_column_vector(up, 1);
+	xform.set_column_vector(refl, 2);
+
+	float phi = acos(pow(randf(), 1.0 / (shininess + 1)));
+	float theta = 2.0 * M_PI * randf();
+
+	Vector3 v;
+	v.x = cos(theta) * sin(phi);
+	v.y = sin(theta) * sin(phi);
+	v.z = cos(phi);
+	v.transform(xform);
+	return v;
+}
+
+float PhongRefl::eval(const Vector3 &norm, const Vector3 &outdir, const Vector3 &indir) const
+{
+	Vector3 refl = outdir.reflection(norm);
+	float dot = std::max<float>(dot_product(indir, refl), 0.0f);
+	return pow(dot, shininess);
+}
diff -r 0ced900e15a7 -r 4a0a288ffb27 liberebus/src/brdf.h
--- a/liberebus/src/brdf.h	Mon Jun 02 00:53:01 2014 +0300
+++ b/liberebus/src/brdf.h	Fri Jun 06 14:39:40 2014 +0300
@@ -53,4 +53,14 @@
 	float eval(const Vector3 &norm, const Vector3 &outdir, const Vector3 &indir) const override;
 };
 
+class PhongRefl : public Reflectance {
+public:
+	float shininess;
+
+	PhongRefl();
+
+	Vector3 sample_dir(const Vector3 &norm, const Vector3 &outdir) const override;
+	float eval(const Vector3 &norm, const Vector3 &outdir, const Vector3 &indir) const override;
+};
+
 #endif	// BRDF_H_
diff -r 0ced900e15a7 -r 4a0a288ffb27 liberebus/src/rt.cc
--- a/liberebus/src/rt.cc	Mon Jun 02 00:53:01 2014 +0300
+++ b/liberebus/src/rt.cc	Fri Jun 06 14:39:40 2014 +0300
@@ -2,7 +2,7 @@
 #include "rt.h"
 #include "erebus_impl.h"
 
-#define MAX_ITER	8
+#define MAX_ITER	6
 
 Color ray_trace(struct erebus *ctx, const Ray &ray, int iter)
 {
@@ -40,14 +40,18 @@
 	Vector2 texcoords = hit.calc_texcoords();
 
 	Color color = mtl->get_attrib_color("diffuse", texcoords.x, texcoords.y);
-	Color res = mtl->get_attrib_color("emissive") + color * scn->get_env().ambient;
+	Color specular = mtl->get_attrib_color("specular", texcoords.x, texcoords.y);
+	Color res = mtl->get_attrib_color("emissive", texcoords.x, texcoords.y) +
+		color * scn->get_env().ambient;
+	float shininess = mtl->get_attrib_value("shininess");
 
 	Vector3 sample_dir;
 	float prob = brdf->sample(norm, -hit.world_ray.dir, &sample_dir);
-	if(iter < max_iter && randf() <= prob) {
+	if(iter < max_iter && randf() <= prob && ray.energy * prob > 0.001) {
 		Ray sample_ray;
 		sample_ray.origin = ray.origin + ray.dir * hit.dist;
 		sample_ray.dir = sample_dir;
+		sample_ray.energy = ray.energy * prob;
 
 		res += ray_trace(ctx, sample_ray, iter + 1) * color;
 	}
diff -r 0ced900e15a7 -r 4a0a288ffb27 liberebus/src/scene.cc
--- a/liberebus/src/scene.cc	Mon Jun 02 00:53:01 2014 +0300
+++ b/liberebus/src/scene.cc	Fri Jun 06 14:39:40 2014 +0300
@@ -140,9 +140,22 @@
 
 bool Scene::load(FILE *fp)
 {
-	static char buf[256];
+	static char buf[4096];
+	int offset = 0;
 
-	while(fgets(buf, sizeof buf, fp)) {
+	while(fgets(buf + offset, sizeof buf - offset, fp)) {
+		// handle line continuations
+		int len = strlen(buf);
+		if(strcmp(buf + len - 2, "\\\n") == 0 || strcmp(buf + len - 2, "\\\r") == 0) {
+			offset = len - 2;
+			continue;
+		}
+		if(strcmp(buf + len - 3, "\\\r\n") == 0) {
+			offset = len - 3;
+			continue;
+		}
+		offset = 0;
+
 		char *line = strip_wspace(buf);
 		if(!line || !*line || *line == '#') {
 			continue;
@@ -198,6 +211,13 @@
 				brdf = new LambertRefl;
 				if(!composite) break;
 
+			} else if(strcmp(argv[i], "phong") == 0) {
+				if(composite && brdf) {
+					composite->add_brdf(brdf, weight);
+				}
+				brdf = new PhongRefl;
+				if(!composite) break;
+
 			} else if(strcmp(argv[i], "mirror") == 0) {
 				if(composite && brdf) {
 					composite->add_brdf(brdf, weight);
diff -r 0ced900e15a7 -r 4a0a288ffb27 test/scene
--- a/test/scene	Mon Jun 02 00:53:01 2014 +0300
+++ b/test/scene	Fri Jun 06 14:39:40 2014 +0300
@@ -1,8 +1,12 @@
 # test scene
 
-sphere -position 0 0 0 -scaling 1 1 1 -diffuse 1 0.6 0.5
+sphere -position 0 0 0 -scaling 1 1 1 -diffuse 1 0.6 0.5 -brdf composite \
+	-brdf lambert -brdf-weight 0.5 \
+	-brdf phong -brdf-weight 0.5
 
-box -position 0 -1.25 0 -scaling 4 0.5 4 -diffuse 0.3 0.4 1.0 -brdf composite -brdf lambert -brdf-weight 0.3 -brdf mirror -brdf-weight 0.7
+box -position 0 -1.25 0 -scaling 4 0.5 4 -diffuse 0.3 0.4 1.0 -brdf composite \
+	-brdf lambert -brdf-weight 0.3 \
+	-brdf mirror -brdf-weight 0.7
 box -position 0 3.75 0 -scaling 20 10 20 -diffuse 1.0 1.0 1.0 -brdf lambert
 
 box -position 0 4 0 -scaling 3 0.1 3 -emissive 6 6 6