Merge pull request #860 from RayTracing/bounding-box

Bounding box

Author: hollasch

CHANGELOG.md

@@ -20,6 +20,7 @@ Change Log -- Ray Tracing in One Weekend
   - Fix: CSS fix for cases where code listing overflow; change to fit content (#826)
   - Change: `hittable` member variable `ptr` renamed to `object`
   - Change: general rename of `mat_ptr` to `mat` (material)
+  - Change: hittable::bounding_box() signature has changed to always return a value (#859)
 
 ### In One Weekend
   - Added: More commentary about the choice between `double` and `float` (#752)

books/RayTracingInOneWeekend.html

@@ -1297,6 +1297,8 @@
             return min <= x && x <= max;
         }
 
+        static const interval empty, universe;
+
       public:
         double min, max;
     };
@@ -1347,7 +1349,7 @@
             return hit_anything;
         }
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-    [Listing [hittable-list-with-interval]: <kbd>[hittable.h]</kbd>
+    [Listing [hittable-list-with-interval]: <kbd>[hittable_list.h]</kbd>
         hittable_list::hit() using interval]
 
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++

books/RayTracingTheNextWeek.html

@@ -809,15 +809,10 @@
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     double f(double d)
     {
-        if(d <= 0.5)
-        {
+        if (d <= 0.5)
             return sqrt(2.0) * random_double();
-        }
         else
-        {
             return sqrt(2.0) + (2 - sqrt(2.0)) * random_double();
-        }
-
     }
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     [Listing [crude-approx]: A crude, first-order approximation to nonuniform PDF]
@@ -1513,6 +1508,7 @@
             return color(0,0,0);
         }
 
+
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++ highlight
         virtual bool scatter(
             const ray& r_in, const hit_record& rec, color& albedo, ray& scattered, double& pdf
@@ -2352,16 +2348,11 @@
             if (!object->hit(r, ray_t, rec))
                 return false;
 
-            if (!object->hit(r, ray_tmin, ray_tmax, rec))
-                return false;
-
             rec.front_face = !rec.front_face;
             return true;
         }
 
-        bool bounding_box(aabb& output_box) const override {
-            return object->bounding_box(output_box);
-        }
+        aabb bounding_box() const override { return object->bounding_box(); }
 
       public:
         shared_ptr<hittable> object;
@@ -2566,7 +2557,7 @@
       public:
         virtual bool hit(const ray& r, interval ray_t, hit_record& rec) const = 0;
 
-        virtual bool bounding_box(aabb& output_box) const = 0;
+        virtual aabb bounding_box() const = 0;
 
 
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++ highlight

books/RayTracingTheRestOfYourLife.html

@@ -19,8 +19,7 @@
 class sphere : public hittable {
   public:
     sphere() {}
-    sphere(point3 ctr, double r, shared_ptr<material> m)
-      : center(ctr), radius(r), mat(m) {};
+    sphere(point3 ctr, double r, shared_ptr<material> m) : center(ctr), radius(r), mat(m) {};
 
     bool hit(const ray& r, interval ray_t, hit_record& rec) const override {
         vec3 oc = r.origin() - center;

src/InOneWeekend/sphere.h

@@ -21,7 +21,9 @@ class xy_rect : public hittable {
     xy_rect() {}
 
     xy_rect(double _x0, double _x1, double _y0, double _y1, double _k, shared_ptr<material> _m)
-      : x0(_x0), x1(_x1), y0(_y0), y1(_y1), k(_k), mat(_m) {};
+      : x0(_x0), x1(_x1), y0(_y0), y1(_y1), k(_k), mat(_m),
+        bbox(point3(x0, y0, k-0.0001), point3(x1, y1, k+0.0001))
+    {}
 
     bool hit(const ray& r, interval ray_t, hit_record& rec) const override {
         auto t = (k-r.origin().z()) / r.direction().z();
@@ -44,16 +46,12 @@ class xy_rect : public hittable {
         return true;
     }
 
-    bool bounding_box(aabb& output_box) const override {
-        // The bounding box must have non-zero width in each dimension, so pad the Z
-        // dimension a small amount.
-        output_box = aabb(point3(x0, y0, k-0.0001), point3(x1, y1, k+0.0001));
-        return true;
-    }
+    aabb bounding_box() const override { return bbox; }
 
   public:
     shared_ptr<material> mat;
     double x0, x1, y0, y1, k;
+    aabb bbox;
 };
 
 
@@ -62,7 +60,9 @@ class xz_rect : public hittable {
     xz_rect() {}
 
     xz_rect(double _x0, double _x1, double _z0, double _z1, double _k, shared_ptr<material> _m)
-      : x0(_x0), x1(_x1), z0(_z0), z1(_z1), k(_k), mat(_m) {};
+      : x0(_x0), x1(_x1), z0(_z0), z1(_z1), k(_k), mat(_m),
+        bbox(point3(x0, k-0.0001, z0), point3(x1, k+0.0001, z1))
+    {}
 
     bool hit(const ray& r, interval ray_t, hit_record& rec) const override {
         auto t = (k-r.origin().y()) / r.direction().y();
@@ -85,16 +85,12 @@ class xz_rect : public hittable {
         return true;
     }
 
-    bool bounding_box(aabb& output_box) const override {
-        // The bounding box must have non-zero width in each dimension, so pad the Y
-        // dimension a small amount.
-        output_box = aabb(point3(x0, k-0.0001, z0), point3(x1, k+0.0001, z1));
-        return true;
-    }
+    aabb bounding_box() const override { return bbox; }
 
   public:
     shared_ptr<material> mat;
     double x0, x1, z0, z1, k;
+    aabb bbox;
 };
 
 
@@ -103,7 +99,9 @@ class yz_rect : public hittable {
     yz_rect() {}
 
     yz_rect(double _y0, double _y1, double _z0, double _z1, double _k, shared_ptr<material> _m)
-      : y0(_y0), y1(_y1), z0(_z0), z1(_z1), k(_k), mat(_m) {};
+      : y0(_y0), y1(_y1), z0(_z0), z1(_z1), k(_k), mat(_m),
+        bbox(point3(k-0.0001, y0, z0), point3(k+0.0001, y1, z1))
+    {}
 
     bool hit(const ray& r, interval ray_t, hit_record& rec) const override {
         auto t = (k-r.origin().x()) / r.direction().x();
@@ -126,16 +124,12 @@ class yz_rect : public hittable {
         return true;
     }
 
-    bool bounding_box(aabb& output_box) const override {
-        // The bounding box must have non-zero width in each dimension, so pad the X
-        // dimension a small amount.
-        output_box = aabb(point3(k-0.0001, y0, z0), point3(k+0.0001, y1, z1));
-        return true;
-    }
+    aabb bounding_box() const override { return bbox; }
 
   public:
     shared_ptr<material> mat;
     double y0, y1, z0, z1, k;
+    aabb bbox;
 };
 
 

src/TheNextWeek/aarect.h

@@ -13,6 +13,7 @@
 
 #include "rtweekend.h"
 
+#include "aabb.h"
 #include "aarect.h"
 #include "hittable_list.h"
 
@@ -21,10 +22,9 @@ class box : public hittable {
   public:
     box() {}
 
-    box(const point3& p0, const point3& p1, shared_ptr<material> mat) {
-        box_min = p0;
-        box_max = p1;
-
+    box(const point3& p0, const point3& p1, shared_ptr<material> mat)
+      : box_min(p0), box_max(p1), bbox(p0, p1)
+    {
         sides.add(make_shared<xy_rect>(p0.x(), p1.x(), p0.y(), p1.y(), p1.z(), mat));
         sides.add(make_shared<xy_rect>(p0.x(), p1.x(), p0.y(), p1.y(), p0.z(), mat));
 
@@ -39,15 +39,13 @@ class box : public hittable {
         return sides.hit(r, ray_t, rec);
     }
 
-    bool bounding_box(aabb& output_box) const override {
-        output_box = aabb(box_min, box_max);
-        return true;
-    }
+    aabb bounding_box() const override { return bbox; }
 
   public:
     point3 box_min;
     point3 box_max;
     hittable_list sides;
+    aabb bbox;
 };
 
 

src/TheNextWeek/box.h

@@ -53,16 +53,11 @@ class bvh_node : public hittable {
             right = make_shared<bvh_node>(objects, mid, end);
         }
 
-        aabb box_left, box_right;
-
-        if (!left->bounding_box(box_left) || !right->bounding_box(box_right))
-            std::cerr << "No bounding box in bvh_node constructor.\n";
-
-        box = aabb(box_left, box_right);
+        bbox = aabb(left->bounding_box(), right->bounding_box());
     }
 
     bool hit(const ray& r, interval ray_t, hit_record& rec) const override {
-        if (!box.hit(r, ray_t))
+        if (!bbox.hit(r, ray_t))
             return false;
 
         bool hit_left = left->hit(r, ray_t, rec);
@@ -71,27 +66,18 @@ class bvh_node : public hittable {
         return hit_left || hit_right;
     }
 
-    bool bounding_box(aabb& output_box) const override {
-        output_box = box;
-        return true;
-    }
+    aabb bounding_box() const override { return bbox; }
 
   public:
     shared_ptr<hittable> left;
     shared_ptr<hittable> right;
-    aabb box;
+    aabb bbox;
 
   private:
     static bool box_compare(
         const shared_ptr<hittable> a, const shared_ptr<hittable> b, int axis_index
     ) {
-        aabb box_a;
-        aabb box_b;
-
-        if (!a->bounding_box(box_a) || !b->bounding_box(box_b))
-            std::cerr << "No bounding box in bvh_node constructor.\n";
-
-        return box_a.axis(axis_index).min < box_b.axis(axis_index).min;
+        return a->bounding_box().axis(axis_index).min < b->bounding_box().axis(axis_index).min;
     }
 
     static bool box_x_compare (const shared_ptr<hittable> a, const shared_ptr<hittable> b) {

src/TheNextWeek/bvh.h

@@ -35,7 +35,7 @@ class constant_medium : public hittable {
 
         hit_record rec1, rec2;
 
-        if (!boundary->hit(r, universe, rec1))
+        if (!boundary->hit(r, interval::universe, rec1))
             return false;
 
         if (!boundary->hit(r, interval(rec1.t+0.0001, infinity), rec2))
@@ -75,9 +75,7 @@ class constant_medium : public hittable {
         return true;
     }
 
-    bool bounding_box(aabb& output_box) const override {
-        return boundary->bounding_box(output_box);
-    }
+    aabb bounding_box() const override { return boundary->bounding_box(); }
 
   public:
     shared_ptr<hittable> boundary;

src/TheNextWeek/constant_medium.h

@@ -40,14 +40,17 @@ class hittable {
   public:
     virtual bool hit(const ray& r, interval ray_t, hit_record& rec) const = 0;
 
-    virtual bool bounding_box(aabb& output_box) const = 0;
+    virtual aabb bounding_box() const = 0;
 };
 
 
 class translate : public hittable {
   public:
     translate(shared_ptr<hittable> p, const vec3& displacement)
-      : object(p), offset(displacement) {}
+      : object(p), offset(displacement)
+    {
+        bbox = object->bounding_box() + offset;
+    }
 
     bool hit(const ray& r, interval ray_t, hit_record& rec) const override {
         ray moved_r(r.origin() - offset, r.direction(), r.time());
@@ -60,17 +63,12 @@ class translate : public hittable {
         return true;
     }
 
-    bool bounding_box(aabb& output_box) const override {
-        if (!object->bounding_box(output_box))
-            return false;
-
-        output_box += offset;
-        return true;
-    }
+    aabb bounding_box() const override { return bbox; }
 
   public:
     shared_ptr<hittable> object;
     vec3 offset;
+    aabb bbox;
 };
 
 
@@ -80,7 +78,7 @@ class rotate_y : public hittable {
         auto radians = degrees_to_radians(angle);
         sin_theta = sin(radians);
         cos_theta = cos(radians);
-        hasbox = object->bounding_box(bbox);
+        bbox = object->bounding_box();
 
         point3 min( infinity,  infinity,  infinity);
         point3 max(-infinity, -infinity, -infinity);
@@ -138,16 +136,12 @@ class rotate_y : public hittable {
         return true;
     }
 
-    bool bounding_box(aabb& output_box) const override {
-        output_box = bbox;
-        return hasbox;
-    }
+    aabb bounding_box() const override { return bbox; }
 
   public:
     shared_ptr<hittable> object;
     double sin_theta;
     double cos_theta;
-    bool hasbox;
     aabb bbox;
 };