Add a camera class

4 files changed, 38 insertions, 26 deletions

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 268dd02..996db85 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1,3 +1,3 @@
 include_directories(${CMAKE_SOURCE_DIR}/include)
 
-add_executable(path-tracer main.cpp vec3.cpp color.cpp ray.cpp sphere.cpp hittable_list.cpp)
+add_executable(path-tracer main.cpp vec3.cpp color.cpp ray.cpp sphere.cpp hittable_list.cpp camera.cpp)
diff --git a/src/camera.cpp b/src/camera.cpp
new file mode 100644
index 0000000..cd43359
--- /dev/null
+++ b/src/camera.cpp
@@ -0,0 +1,22 @@
+#include "camera.hpp"
+
+camera::camera(point3 position, double aspect_ratio, double focal_length)
+    : position(position), focal_length(focal_length) {
+    auto viewport_height = 2.0;
+    auto viewport_width =  viewport_height * aspect_ratio;
+
+    horizontal = vec3 { viewport_width, 0.0, 0.0 };
+    vertical = vec3 { 0.0, viewport_height, 0.0 };
+
+    bottom_left_pixel = position - horizontal / 2.0 - vertical / 2.0 - vec3 { 0.0, 0.0, focal_length };
+
+    std::cerr << bottom_left_pixel << std::endl;
+}
+
+ray camera::get_ray(double u, double v) const {
+    point3 viewport_pixel = bottom_left_pixel + u * horizontal + v * vertical;
+    return ray {
+        position,
+        viewport_pixel - position
+    };
+}
diff --git a/src/color.cpp b/src/color.cpp
index 53a79f9..b0e60e1 100644
--- a/src/color.cpp
+++ b/src/color.cpp
@@ -1,7 +1,11 @@
 #include "color.hpp"
 
-void write_color(std::ostream& out, const color& pixel_color) {
-    out << static_cast<uint32_t>(255.0 * pixel_color.x) << ' '
-        << static_cast<uint32_t>(255.0 * pixel_color.y) << ' '
-        << static_cast<uint32_t>(255.0 * pixel_color.z) << std::endl;
+void write_color(std::ostream& out, const color& pixel_color, uint32_t samples_per_pixel) {
+
+    auto scale = 1.0 / samples_per_pixel;
+    auto scaled_color = pixel_color * scale;
+
+    out << static_cast<uint32_t>(255.0 * scaled_color.x) << ' '
+        << static_cast<uint32_t>(255.0 * scaled_color.y) << ' '
+        << static_cast<uint32_t>(255.0 * scaled_color.z) << std::endl;
 }
diff --git a/src/main.cpp b/src/main.cpp
index f6b3012..15fd165 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -42,17 +42,7 @@ int main() {
     const vec3 vertical { 0.0, viewport_height / height, 0.0 };
 
     // We use a right handed coord system
-    const point3 eye_pos {};
-    const double focal_length = 1.0;
-
-    const point3 viewport_first_pixel {
-        -viewport_width / 2.0,
-        -viewport_height / 2.0,
-        -focal_length
-    };
-
-    const point3 first_pixel = eye_pos + viewport_first_pixel;
-    std::cerr << viewport_first_pixel << std::endl;
+    camera camera { {}, aspect_ratio, 1.0 };
 
     // PPM format header
     std::cout << "P3\n" << width << '\n' << height << "\n 255" << std::endl;
@@ -60,18 +50,14 @@ int main() {
     std::cerr << "Generating image" << std::endl;
 
     for (ssize_t row = height - 1; row >= 0; row--) {
-        std::cerr << row << " lines remaining" << std::endl;
+        // std::cerr << row << " lines remaining" << std::endl;
         for (size_t column = 0; column < width; column++) {
-            vec3 x = horizontal * column;
-            vec3 y = vertical * row;
-
-            vec3 pixel_pos = first_pixel + x + y;
-            vec3 direction = pixel_pos - eye_pos;
-
-            ray ray { eye_pos, direction };
+            auto u = double(column) / (width - 1.0);
+            auto v = double(row) / (height - 1.0);
+            auto ray = camera.get_ray(u, v);
 
-            write_color(std::cout, ray_color(ray, world));
-            // write_color(std::cout, color(direction.unit().y, direction.unit().y, direction.unit().y));
+            write_color(std::cout, ray_color(ray, world), 1.0);
+            // write_color(std::cout, color(ray.direction.unit().y, ray.direction.unit().y, ray.direction.unit().y));
             // write_color(std::cout, color(y.y, y.y, y.y));
         }
     }