From bcbc0719b38169f9b122461ae2857f7ab9344387 Mon Sep 17 00:00:00 2001
From: K Tyl <me@ktyl.dev>
Date: Sat, 6 Jun 2020 18:28:30 +0100
Subject: [PATCH] add hittable world

---
 src/main.cpp | 45 +++++++++++++++------------------------------
 1 file changed, 15 insertions(+), 30 deletions(-)

diff --git a/src/main.cpp b/src/main.cpp
index a329384..5a5220e 100755
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1,6 +1,8 @@
+#include "rtweekend.h"
+
+#include "hittable_list.h"
+#include "sphere.h"
 #include "colour.h"
-#include "vec3.h"
-#include "ray.h"
 
 #include <iostream>
 
@@ -8,37 +10,16 @@ const double ASPECT_RATIO = 16.0 / 9.0;
 const int WIDTH = 384;
 const int HEIGHT = static_cast<int>(WIDTH / ASPECT_RATIO);
 
-double hit_sphere(const point3& centre, double radius, const ray& r)
+colour ray_colour(const ray& r, const hittable& world)
 {
-    vec3 oc = r.origin() - centre;
-
-    auto a = r.direction().length_squared();
-    auto half_b = dot(oc, r.direction());
-    auto c = oc.length_squared() - radius*radius;
-
-    auto discriminant = half_b*half_b - a*c;
-
-    if (discriminant < 0)
+    hit_record rec;
+    if (world.hit(r, 0, infinity, rec))
     {
-        return -1.0;
-    }
-    else
-    {
-        return (-half_b - sqrt(discriminant)) / a;
-    }
-}
-
-colour ray_colour(const ray& r)
-{
-    auto t = hit_sphere(point3(0,0,-1), 0.5, r);
-    if (t > 0.0)
-    {
-        vec3 N = unit_vector(r.at(t) - vec3(0,0,-1));
-        return 0.5*colour(N.x()+1, N.y()+1, N.z()+1);
+        return 0.5 * (rec.normal + colour(1,1,1));
     }
 
     vec3 unit_direction = unit_vector(r.direction());
-    t = 0.5 * (unit_direction.y() + 1.0);
+    auto t = 0.5 * (unit_direction.y() + 1.0);
 
     auto a = colour(1.0, 0.5, 0.6);
     auto b = colour(0.0, 0.0, 0.0);
@@ -48,6 +29,8 @@ colour ray_colour(const ray& r)
 
 int main()
 {
+    std::cout << "P3\n" << WIDTH << ' ' << HEIGHT << "\n255\n";
+
     auto viewport_height = 2.0;
     auto viewport_width = ASPECT_RATIO * viewport_height;
     auto focal_length = 1.0;
@@ -57,7 +40,9 @@ int main()
     auto vertical = vec3(0, viewport_height, 0);
     auto lower_left_corner = origin - horizontal/2 - vertical/2 - vec3(0,0,focal_length);
 
-    std::cout << "P3\n" << WIDTH << ' ' << HEIGHT << "\n255\n";
+    hittable_list world;
+    world.add(make_shared<sphere>(point3(0,0,-1), 0.5));
+    world.add(make_shared<sphere>(point3(0,-100.5,-1), 100));
 
     for (int y = HEIGHT - 1; y >= 0; --y)
     {
@@ -68,7 +53,7 @@ int main()
             auto v = double(y) / (HEIGHT-1);
             ray r(origin, lower_left_corner + u*horizontal + v*vertical - origin);
             
-            colour pixel_colour = ray_colour(r);
+            colour pixel_colour = ray_colour(r, world);
             write_colour(std::cout, pixel_colour);
         }
     }