Clean up camera module

src/camera.cc

@@ -12,9 +12,7 @@
 #pragma mark - Generic Camera
 
 Camera::Camera()
-    : height(Vector3::Y),
-      width(4.0 / 3.0 * Vector3::X),
-      direction(Vector3::Z),
+    : direction(Vector3::Z),
       mRight(1.33, 0, 0),
       mUp(Vector3::Y)
 { }
@@ -24,41 +22,6 @@ Camera::~Camera()
 { }
 
 
-/*
- * Camera::get_width --
- * Camera::set_width --
- * Camera::get_height --
- * Camera::set_height --
- *
- * Get and set width and height vectors.
- */
-const Vector3 &
-Camera::get_width()
-    const
-{
-    return width;
-}
-
-void
-Camera::set_width(const Vector3 &w)
-{
-    width = w;
-}
-
-const Vector3 &
-Camera::get_height()
-    const
-{
-    return height;
-}
-
-void
-Camera::set_height(const Vector3 &h)
-{
-    height = h;
-}
-
-
 /*
  * Camera::get_direction --
  * Camera::set_direction --
@@ -148,13 +111,15 @@ OrthographicCamera::compute_primary_ray(const int x,
                                         const int height)
     const
 {
-    // Calculate the point on the image plane that the given (x,y) coordinate pair corresponds to.
-    float dir_x = (x / width) + 0.5;
-    float dir_y = (y / height) + 0.5;
-    Vector3 ray_origin = (dir_x * get_width()) + (dir_y * get_height()) + get_direction();
+    /*
+     * Center x and y in the pixel and convert them to be coordinates between
+     * -0.5 and 0.5.
+     */
+    double x0 = (x + 0.5) / width + 0.5;
+    double y0 = ((height - 1.0) - (y - 0.5)) / height - 0.5;
 
-    // Calculate the direction of the ray, given the camera's origin and normalize that vector.
-    Vector3 ray_direction = (ray_origin - get_origin()).normalize();
-
-    return Ray(ray_origin, ray_direction);
+    Vector3 origin = LinearCombination(1.0, get_origin(),
+                                       x0, GetRight(),
+                                       y0, GetUp());
+    return Ray(origin, get_direction());
 }