Camera rotation

src/main/java/labs/introtoprogramming/lab5/Main.java

@@ -7,6 +7,7 @@
 import labs.introtoprogramming.lab5.gui.SceneRendererWindow;
 import labs.introtoprogramming.lab5.scene.Scene;
 import labs.introtoprogramming.lab5.scene.Camera;
+import labs.introtoprogramming.lab5.scene.SceneObject;
 import labs.introtoprogramming.lab5.scene.Transform;
 import labs.introtoprogramming.lab5.scenes.DemoScene;
 
@@ -22,9 +23,11 @@ public static void main(String[] args) {
 
   private void run() {
     Scene demoScene = new DemoScene();
+    SceneObject empty = new SceneObject();
     Camera camera = createCamera();
+    camera.getTransform().setParent(empty.getTransform());
     demoScene.addSceneObjects(camera);
-    demoScene.addController(new KeyAndMouseMovementController(camera));
+    demoScene.addController(new KeyAndMouseMovementController(empty));
 
     SceneRendererWindow window = new SceneRendererWindow(demoScene);
     window.setTitle(APP_TILE);

src/main/java/labs/introtoprogramming/lab5/scene/BasicRaytracingRender.java

@@ -25,13 +25,14 @@ public BasicRaytracingRender(Raster raster) {
   @Override
   public void render(Scene scene) {
     Camera camera = scene.getCamera().orElseThrow(NoCameraException::new);
+    Transform transform = camera.getTransform();
     Vector3 pos = camera.getTransform().position();
     int width = raster.getWidth();
     int height = raster.getHeight();
     double aspectRatio = camera.aspectRatio();
     double fieldOfView = Math.tan(camera.fieldOfView() / 2);
     Ray primaryRay = new Ray(pos, Vector3.ZERO);
-    Transform transform = camera.getTransform();
+    primaryRay.setOrigin(transform.applyPoint(transform.position()));
     for (int y = 0; y < height; y++) {
       double normalizedY = 1 - 2 * (y + 0.5) / height;
       double cameraY =  normalizedY * fieldOfView;
@@ -40,7 +41,6 @@ public void render(Scene scene) {
         double cameraX = normalizedX * aspectRatio * fieldOfView;
         Vector3 direction = new Vector3(cameraX, cameraY, -1).normalize();
         primaryRay.setDirection(transform.applyVector(direction).normalize());
-        primaryRay.setOrigin(transform.applyPoint(transform.position()));
         Color color = getColor(primaryRay, scene);
         raster.setPixel(x, y,
                 (byte) color.getRed(),

src/main/java/labs/introtoprogramming/lab5/scene/Transform.java

@@ -8,6 +8,7 @@ public class Transform {
   private Vector3 rotation;
   private Vector3 scale;
   private Matrix44 matrix;
+  private Transform parent;
 
   /**
    * Container of object transformations.
@@ -65,6 +66,9 @@ public void setScale(Vector3 scale) {
    * @return transformed vector to local space
    */
   public Vector3 applyVector(Vector3 v) {
+    if (parent != null) {
+      v = parent.applyVector(v);
+    }
     return matrix.applyVector(v);
   }
 
@@ -75,6 +79,9 @@ public Vector3 applyVector(Vector3 v) {
    * @return transformed point to local space
    */
   public Vector3 applyPoint(Vector3 v) {
+    if (parent != null) {
+      v = parent.applyPoint(v);
+    }
     return matrix.applyPoint(v);
   }
 
@@ -89,4 +96,8 @@ public Vector3 applyPoint(Vector3 v) {
   public void setMatrix(Vector3 right, Vector3 up, Vector3 forward, Vector3 translate) {
     matrix.setMatrix(right, up, forward, translate);
   }
+
+  public void setParent(Transform parent) {
+    this.parent = parent;
+  }
 }