1 files changed, 64 insertions, 0 deletions
diff --git a/view.h b/view.h
new file mode 100644
index 0000000..e27176e
--- /dev/null
+++ b/view.h
@@ -0,0 +1,64 @@
+#ifndef VIEW_H
+#define VIEW_H
+
+#include "random.h"
+#include "vec3.h"
+
+#include <cmath>
+
+struct View
+{
+    static constexpr auto lookat = point3(0, 0, -1); // Point camera is looking at
+    static constexpr auto vup    = vec3(0, 1, 0);    // Camera-relative "up" direction
+
+    float fieldOfView = 90.f;
+    float focalLength;
+    float viewportHeight;
+    float viewportWidth;
+
+    point3 camera;
+    vec3 viewportX;
+    vec3 viewportY;
+    vec3 pixelDX;
+    vec3 pixelDY;
+    vec3 viewportUL;
+    vec3 pixelUL;
+
+    View() {
+        recalculate();
+    }
+
+    void recalculate() {
+        focalLength = (camera - lookat).length();
+        viewportHeight = 2 * std::tan(fieldOfView * 3.14159265 / 180.0 / 2.0) * focalLength;
+        viewportWidth  = viewportHeight * Aspect;
+
+        const auto w = (camera - lookat).normalize();
+        const auto u = cross(vup, w).normalize();
+        const auto v = cross(w, u);
+
+        viewportX = viewportWidth * u;
+        viewportY = -viewportHeight * v;
+
+        pixelDX = viewportX / Width;
+        pixelDY = viewportY / Height;
+        viewportUL = camera - focalLength * w - viewportX / 2 - viewportY / 2;
+        pixelUL = viewportUL + 0.5 * (pixelDX + pixelDY);
+    }
+
+    ray getRay(int x, int y, bool addRandom = false) const {
+        double X = x;
+        double Y = y;
+
+        if (addRandom) {
+            X += randomN() - 0.5;
+            Y += randomN() - 0.5;
+        }
+
+        auto pixel = pixelUL + X * pixelDX + Y * pixelDY;
+        return ray(camera, pixel - camera);
+    }
+};
+
+#endif // VIEW_H
+