diff --git a/camera.h b/camera.h
index f87f2af..d85f555 100644
--- a/camera.h
+++ b/camera.h
@@ -1,20 +1,30 @@
 #ifndef CAMERA_H
 #define CAMERA_H
 
+#include <cmath>
+
 #include "vec3.h"
 
 class Camera {
 public:
-  Camera() {
-    auto aspect_ratio = 16.0 / 9.0;
-    auto viewport_height = 2.0;
+  Camera(Point3 lookfrom,
+          Point3 lookat,
+          Vec3 vup,
+          double vfov, // vertical field-of-view in degrees
+          double aspect_ratio) {
+    auto theta = degrees_to_radians(vfov);
+    auto h = std::tan(theta/2);
+    auto viewport_height = 2.0 * h;
     auto viewport_width = aspect_ratio * viewport_height;
-    auto focal_length = 1.0;
 
-    origin = Point3(0, 0, 0);
-    horizontal = Vec3(viewport_width, 0.0, 0.0);
-    vertical = Vec3(0.0, viewport_height, 0.0);
-    lower_left_corner = origin - horizontal / 2 - vertical / 2 - Vec3(0, 0, focal_length);
+    auto w = unit_vector(lookfrom - lookat);
+    auto u = unit_vector(cross(vup, w));
+    auto v = cross(w, u);
+
+    origin = lookfrom;
+    horizontal = viewport_width * u;
+    vertical = viewport_height * v;
+    lower_left_corner = origin - horizontal / 2 - vertical / 2 - w;
   }
 
   Ray get_ray(double u, double v) const {
diff --git a/wtracer.cpp b/wtracer.cpp
index 9752d4b..eabefbf 100644
--- a/wtracer.cpp
+++ b/wtracer.cpp
@@ -49,8 +49,9 @@ int main() {
 
 
     world.add(std::make_shared<Sphere>(Point3(-1, 0, -1), 0.5, std::make_shared<Dielectric>(1.45)));
+    world.add(std::make_shared<Sphere>(Point3(-1, 0, -1), -0.45, std::make_shared<Dielectric>(1.45)));
 
-    Camera cam;
+    Camera cam(Point3(-2, 2, 1), Point3(0, 0, -1), Vec3(0, 1, 0), 75, aspect_ratio);
 
     auto image = std::make_unique<Color[]>(image_height*image_width);