Movable and rotatable camera + dielectric materials

1 files changed, 15 insertions, 7 deletions

diff --git a/src/camera.cpp b/src/camera.cpp
index 21cf506..520cc1e 100644
--- a/src/camera.cpp
+++ b/src/camera.cpp
@@ -1,14 +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;
+#include "rt.hpp"
 
-    horizontal = vec3 { viewport_width, 0.0, 0.0 };
-    vertical = vec3 { 0.0, viewport_height, 0.0 };
+camera::camera(point3 position, point3 target, double v_fov, double aspect_ratio)
+    : position(position) {
 
-    bottom_left_pixel = position - horizontal / 2.0 - vertical / 2.0 - vec3 { 0.0, 0.0, focal_length };
+    auto forward = (position - target).unit();
+    auto right = vec3{ 0.0, 1.0, 0.0 }.cross(forward).unit();
+    auto up = forward.cross(right).unit();
+
+    auto h = tan(deg_to_rad(v_fov) / 2.0);
+    auto viewport_height = 2.0 * h;
+    auto viewport_width = viewport_height * aspect_ratio;
+
+    horizontal = viewport_width * right;
+    vertical = viewport_height * up;
+
+    bottom_left_pixel = position - horizontal / 2.0 - vertical / 2.0 - forward;
 }
 
 ray camera::get_ray(double u, double v) const {