Updates from progression 3, 2024-0722

Author: hollasch

books/RayTracingTheRestOfYourLife.html

@@ -1818,7 +1818,7 @@
 see.
 
   ![<span class='num'>Image 4:</span> Cornell box, with imperfect PDF
-  ](../images/img-3.04-cornell-refactor2.jpg class='pixel')
+  ](../images/img-3.04-cornell-imperfect.jpg class='pixel')
 
 Make sure to return the PDF to the scattering PDF.
 
@@ -1870,7 +1870,6 @@
             return true;
         }
 
-
         double scattering_pdf(const ray& r_in, const hit_record& rec, const ray& scattered)
         const override {
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++ highlight
@@ -1887,7 +1886,7 @@
 our uniform hemispherical diffuse. When rendering, we should get a slightly different image.
 
   ![<span class='num'>Image 5:</span> Cornell box, with uniform hemispherical sampling
-  ](../images/img-3.04-cornell-refactor2.jpg class='pixel')
+  ](../images/img-3.05-cornell-uniform-hemi.jpg class='pixel')
 
 It’s pretty close to our old picture, but there are differences that are not just noise. The front
 of the tall box is much more uniform in color. If you aren't sure what the best sampling pattern for
@@ -2399,7 +2398,7 @@
             ray scattered;
             color attenuation;
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++ highlight
-            double pdf_value; // TODO: What are we supposed to do with the returned PDF?
+            double pdf_value;
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++
             color color_from_emission = rec.mat->emitted(rec.u, rec.v, rec.p);
 
@@ -2409,6 +2408,11 @@
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++
                 return color_from_emission;
 
+            double scattering_pdf = rec.mat->scattering_pdf(r, rec, scattered);
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++ highlight
+            pdf_value = scattering_pdf;
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++
+
             ...
         }
 
@@ -2536,7 +2540,7 @@
 
             ray scattered;
             color attenuation;
-            double pdf_value; // TODO: What are we supposed to do with the returned PDF?
+            double pdf_value;
             color color_from_emission = rec.mat->emitted(rec.u, rec.v, rec.p);
 
             if (!rec.mat->scatter(r, rec, attenuation, scattered, pdf_value))
@@ -2798,7 +2802,7 @@
 
             ray scattered;
             color attenuation;
-            double pdf_value; // TODO: What are we supposed to do with the returned PDF?
+            double pdf_value;
             color color_from_emission = rec.mat->emitted(r, rec, rec.u, rec.v, rec.p);
 
             if (!rec.mat->scatter(r, rec, attenuation, scattered, pdf_value))
@@ -2869,6 +2873,8 @@
 
     ...
 
+
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++ highlight
     class hittable_pdf : public pdf {
       public:
         hittable_pdf(const hittable& objects, const point3& origin)
@@ -3034,15 +3040,15 @@
 
             ray scattered;
             color attenuation;
-            double pdf_value; // TODO: What are we supposed to do with the returned PDF?
+            double pdf_value;
             color color_from_emission = rec.mat->emitted(r, rec, rec.u, rec.v, rec.p);
 
             if (!rec.mat->scatter(r, rec, attenuation, scattered, pdf_value))
                 return color_from_emission;
 
 
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++ highlight
-            hittable_pdf light_pdf(light_ptr, rec.p);
+            hittable_pdf light_pdf(lights, rec.p);
             scattered = ray(rec.p, light_pdf.generate(), r.time());
             pdf_value = light_pdf.value(scattered.direction());
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++
@@ -3084,6 +3090,15 @@
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++
 
         camera cam;
+
+        cam.aspect_ratio      = 1.0;
+        cam.image_width       = 600;
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++ highlight
+        cam.samples_per_pixel = 10;
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++
+        cam.max_depth         = 50;
+        cam.background        = color(0,0,0);
+
         ...
 
 
@@ -3203,7 +3218,7 @@
 
 
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++ highlight
-            auto p0 = make_shared<hittable_pdf>(light_ptr, rec.p);
+            auto p0 = make_shared<hittable_pdf>(lights, rec.p);
             auto p1 = make_shared<cosine_pdf>(rec.normal);
             mixture_pdf mixed_pdf(p0, p1);
 
@@ -3224,7 +3239,7 @@
 </div>
 
 <div class='together'>
-1000 samples per pixel yields:
+Updating `main.cc` to 1000 samples per pixel (not listed) yields:
 
   ![<span class='num'>Image 11:</span> Cornell box, mixture density of cosine and light sampling
   ](../images/img-3.11-cosine-and-light.jpg class='pixel')
@@ -3311,6 +3326,15 @@
 <div class='together'>
 We can redesign `material` and stuff all the new arguments into a class like we did for `hittable`:
 
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++
+    #include "rtweekend.h"
+
+    #include "onb.h"
+    #include "texture.h"
+
+    class hit_record;
+
+
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++ highlight
     class scatter_record {
       public:
@@ -3513,8 +3537,6 @@
         double fuzz;
     };
 
-    ...
-
     class dielectric : public material {
       public:
         dielectric(double refraction_index) : refraction_index(refraction_index) {}
@@ -3717,6 +3739,8 @@
       public:
         ...
 
+        aabb bounding_box() const override { return bbox; }
+
 
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++ highlight
         double pdf_value(const point3& origin, const vec3& direction) const override {
@@ -3818,6 +3842,8 @@
       public:
         ...
 
+        aabb bounding_box() const override { return bbox; }
+
 
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++ highlight
         double pdf_value(const point3& origin, const vec3& direction) const override {
@@ -3854,7 +3880,7 @@
         hittable_list lights;
         lights.add(
             make_shared<quad>(point3(343,554,332), vec3(-130,0,0), vec3(0,0,-105), empty_material));
-        lights.add(make_shared<sphere>(point3(190, 90, 190), 90, m));
+        lights.add(make_shared<sphere>(point3(190, 90, 190), 90, empty_material));
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++
 
         ...

images/img-3.04-cornell-imperfect.jpg

@@ -47,10 +47,11 @@ int main() {
     world.add(make_shared<sphere>(point3(190,90,190), 90, glass));
 
     // Light Sources
+    auto empty_material = shared_ptr<material>();
     hittable_list lights;
-    auto m = shared_ptr<material>();
-    lights.add(make_shared<quad>(point3(343,554,332), vec3(-130,0,0), vec3(0,0,-105), m));
-    lights.add(make_shared<sphere>(point3(190, 90, 190), 90, m));
+    lights.add(
+        make_shared<quad>(point3(343,554,332), vec3(-130,0,0), vec3(0,0,-105), empty_material));
+    lights.add(make_shared<sphere>(point3(190, 90, 190), 90, empty_material));
 
     camera cam;