Defocus blur + Final render

The last of the RaytracingInOneWeekend post.
Very cool thing to go through.

README.md

@@ -1,7 +1,7 @@
 # Raytracing in one weekend
 
 
-[!img]()
+![Movable lens](results/Camerazoom.png)
 
 
 

src/camera.h

@@ -8,7 +8,9 @@ class camera{
             point3 lookat,
             vec3 vup,
             double vfov ,
-            double aspect_ratio
+            double aspect_ratio,
+            double aperture,
+            double focus_dist
         ){
             
              
@@ -18,18 +20,21 @@ class camera{
              auto viewport_height = 2.0 * h;
              auto viewport_width = aspect_ratio * viewport_height;
             
-             auto w = unit_vector(lookfrom - lookat);
-             auto u = unit_vector(cross(vup, w));
-             auto v = cross(w,u);
+             w = unit_vector(lookfrom - lookat);
+             u = unit_vector(cross(vup, w));
+             v = cross(w,u);
 
             origin = lookfrom;
-            horizontal = viewport_width * u;
-            vertical =  viewport_height * v;
-            lower_left_corner = origin - horizontal/2 - vertical/2 - w;
+            horizontal = focus_dist * viewport_width * u;
+            vertical =  focus_dist * viewport_height * v;
+            lower_left_corner = origin - horizontal/2 - vertical/2 - focus_dist * w;
+            lens_radius = aperture /2;
         }
 
         ray get_ray(double s, double t) const {
-            return ray(origin, lower_left_corner + s * horizontal + t*vertical - origin);
+            vec3 rd = lens_radius * random_in_unit_disk();
+            vec3 offset = u * rd.x() + v * rd.y();
+            return ray(origin + offset, lower_left_corner + s * horizontal + t * vertical - origin - offset);
         }
 
         private:
@@ -37,4 +42,6 @@ class camera{
             point3 lower_left_corner;
             vec3 horizontal;
             vec3 vertical;
+            vec3 u,v,w;
+            double lens_radius;
 };

src/program.cpp

@@ -27,33 +27,76 @@ color ray_color(const ray& r, const hittable& world, int depth){
     return (1.0-t)*color(1.0, 1.0, 1.0) + t*color(0.5,0.7,1.0);
 }
 
+hittable_list random_scene(){
+  hittable_list world;
+
+  auto ground_material = make_shared<lambertian>(color(0.5,0.5,0.5));
+  world.add(make_shared<sphere>(point3(0,-1000,0), 1000, ground_material));
+
+  for(int a = -11; a < 11; a++){
+    for(int b = -11; b < 11; b++){
+      auto choose_mat = random_double();
+      point3 center(a + 0.9 * random_double(), 0.2 , b+0.9* random_double());
+
+      if((center - point3(4,0.2,0)).length() > 0.9){
+        shared_ptr<material> sphere_material;
+
+        if(choose_mat < 0.8){
+          // diffuse
+          auto albedo = color::random() * color::random();
+          sphere_material = make_shared<lambertian>(albedo);
+          world.add(make_shared<sphere>(center, 0.2, sphere_material));
+        } 
+        else if(choose_mat < 0.95){
+          // metal
+          auto albedo = color::random(0.5,1);
+          auto fuzz = random_double(0,0.5);
+          sphere_material = make_shared<metal>(albedo, fuzz );
+          world.add(make_shared<sphere>(center, 0.2, sphere_material));
+        }else{
+          // glass
+          sphere_material = make_shared<dielectric>(1.5);
+          world.add(make_shared<sphere>(center, 0.2, sphere_material));
+        }
+      }
+    }
+  }
+
+auto material1 = make_shared<dielectric>(1.5);
+world.add(make_shared<sphere>(point3(0,1,0), 1.0, material1));
+
+auto material2 = make_shared<lambertian>(color(0.4, 0.2, 0.1));
+world.add(make_shared<sphere>(point3(-4,1,0), 1.0, material2));
+
+auto material3 = make_shared<metal>(color(0.7, 0.6, 0.5), 0.0);
+world.add(make_shared<sphere>(point3(4,1,0), 1.0, material3));
+
+return world;
+
+
+}
+
 
 int main ()
 {
     // Image 
-    const auto aspect_ratio = 16.0 /9.0;
-    const int image_width = 400;
+    const auto aspect_ratio = 3.0 /2.0;
+    const int image_width = 1200;
     const int image_height = static_cast<int>(image_width /aspect_ratio);
-    const int samples_per_pixel = 100; 
+    const int samples_per_pixel = 500; 
     const int max_depth = 50;
 
     // World 
-    hittable_list world;
-
-    auto material_ground = make_shared<lambertian>(color(0.8, 0.8, 0.0));
-    auto material_center = make_shared<lambertian>(color(0.1, 0.2, 0.5));
-    auto material_left   = make_shared<dielectric>(1.5);
-    auto material_right  = make_shared<metal>(color(0.8, 0.6, 0.2), 0.0);
-
-    world.add(make_shared<sphere>(point3( 0.0, -100.5, -1.0), 100.0, material_ground));
-    world.add(make_shared<sphere>(point3( 0.0,    0.0, -1.0),   0.5, material_center));
-    world.add(make_shared<sphere>(point3(-1.0,    0.0, -1.0),   0.5, material_left));
-    world.add(make_shared<sphere>(point3(-1.0,    0.0, -1.0), -0.45, material_left));
-    world.add(make_shared<sphere>(point3( 1.0,    0.0, -1.0),   0.5, material_right));
-
+    auto world = random_scene();
 
     // Camera
-    camera cam(point3(-2,2,1), point3(0,0,-1), vec3(0,1,0), 20, aspect_ratio);
+    point3 lookfrom(13,2,3);
+    point3 lookat(0,0,0);
+    vec3 vup(0,1,0);
+    auto dist_to_focus = 10.0;
+    auto aperture = 0.1;
+
+    camera cam(lookfrom, lookat , vup, 20, aspect_ratio, aperture, dist_to_focus);
 
     // Render
     std::cout<< "P3\n" << image_width << ' ' << image_height << "\n255\n";

src/vector3.h

@@ -137,4 +137,12 @@ vec3 refract(const vec3& uv, const vec3& n, double etai_over_etat){
     vec3 r_out_perp = etai_over_etat * (uv + cos_theta*n);
     vec3 r_out_parallel = -sqrt(fabs(1.0 - r_out_perp.length_squared())) * n;
     return r_out_perp + r_out_parallel; 
+}
+
+vec3 random_in_unit_disk(){
+    while(true){
+        auto p = vec3(random_double(-1,1) , random_double(-1,1), 0);
+        if(p.length_squared() >= 1) continue;
+        return p;
+    }
 }