feat(shading): basic shading

src/main/java/labs/introtoprogramming/lab5/object/Sphere.java

@@ -20,6 +20,7 @@ public Sphere(Transform transform, double radius) {
     this.radius = radius;
   }
 
+  @SuppressWarnings("Duplicates")
   @Override
   public boolean intersect(Ray ray) {
     Vector3 originToCenter = transform.position().subtract(ray.getOrigin());
@@ -55,4 +56,8 @@ public Box getBoundary() {
     Vector3 size = Vector3.ONE.multiply(radius);
     return new Box(new Transform(), pos.subtract(size), pos.add(size));
   }
+
+  public Vector3 getNormal(Vector3 hitPoint) {
+    return hitPoint.subtract(transform.position()).normalize();
+  }
 }

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

@@ -8,7 +8,11 @@
 import java.awt.Color;
 
 public class BasicRaytracingRender implements SceneRender {
+
+  private static final boolean DEFAULT_APPLY_SHADING = true;
+
   private Raster raster;
+  private boolean applyShading = DEFAULT_APPLY_SHADING;
 
   public BasicRaytracingRender(Scene scene) {
     this(scene.getCamera().orElseThrow(NoCameraException::new));
@@ -52,12 +56,40 @@ public void render(Scene scene) {
 
   Color getColor(Ray primaryRay, Scene scene) {
     SceneObject obj = findInteraction(primaryRay, scene);
-    return obj != null ? obj.getMesh().color() : scene.getBackgroundColor();
+
+    if (obj == null) {
+      return scene.getBackgroundColor();
+    }
+
+    if (!applyShading) {
+      return obj.getMesh().color();
+    }
+
+    double c = 0;
+
+    for (Light light : scene.getLights()) {
+      Vector3 hitNormal = obj.getNormal(primaryRay.getPoint());
+      double bias = 0.001;
+      Ray nRay = new Ray(primaryRay.getPoint().add(hitNormal.multiply(bias)), light.getTransform().rotation().multiply(-1));
+      boolean visible = findInteraction(nRay, scene, light.getMaxDist(primaryRay.getPoint())) == null;
+      if (visible) {
+        c += obj.albedo() / Math.PI * light.illuminate(hitNormal, light.getTransform().position().distance(obj.getTransform().position()));
+      }
+    }
+
+    if (c > 1) {
+      c = 1;
+    }
+
+    return new Color((int) (obj.getMesh().color().getRed() * c), (int) (obj.getMesh().color().getGreen() * c), (int) (obj.getMesh().color().getBlue() * c));
   }
 
   SceneObject findInteraction(Ray primaryRay, Scene scene) {
+    return findInteraction(primaryRay, scene, Double.POSITIVE_INFINITY);
+  }
+
+  SceneObject findInteraction(Ray primaryRay, Scene scene, double minDistance) {
     SceneObject intersection = null;
-    double minDistance = Double.POSITIVE_INFINITY;
     for (SceneObject obj : scene.getSceneObjects()) {
       if (obj.intersect(primaryRay)) {
         double distance = primaryRay.getScale();
@@ -67,6 +99,9 @@ SceneObject findInteraction(Ray primaryRay, Scene scene) {
         }
       }
     }
+    if (intersection != null) {
+      primaryRay.setScale(minDistance);
+    }
     return intersection;
   }
 }

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

@@ -37,10 +37,10 @@ public List<SceneObject> getSceneObjects() {
   }
 
   @Override
-  public List<PointLight> getLights() {
+  public List<Light> getLights() {
     return entities.stream()
-            .filter(obj -> obj instanceof PointLight)
-            .map(obj -> (PointLight) obj)
+            .filter(obj -> obj instanceof Light)
+            .map(obj -> (Light) obj)
             .collect(Collectors.toList());
   }
 

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

@@ -0,0 +1,22 @@
+package labs.introtoprogramming.lab5.scene;
+
+import java.awt.Color;
+import labs.introtoprogramming.lab5.geometry.Vector3;
+
+public class DistantLight extends Light {
+
+  Vector3 direction;
+
+  public DistantLight(Transform transform, double intensity) {
+    super(transform, intensity);
+  }
+
+  @Override
+  public double illuminate(Vector3 normal, double distance) {
+    return Math.max(intensity() * normal.dotProduct(getTransform().rotation().multiply(-1)), 0);
+  }
+
+  public double getMaxDist(Vector3 point) {
+    return Double.POSITIVE_INFINITY;
+  }
+}

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

@@ -0,0 +1,21 @@
+package labs.introtoprogramming.lab5.scene;
+
+import labs.introtoprogramming.lab5.geometry.Vector3;
+
+public abstract class Light extends SceneObject {
+
+  private double intensity;
+
+  public Light(Transform transform, double intensity) {
+    super(transform);
+    this.intensity = intensity;
+  }
+
+  public double intensity() {
+    return intensity;
+  }
+
+  public abstract double illuminate(Vector3 normal, double distance);
+
+  public abstract double getMaxDist(Vector3 point);
+}

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

@@ -1,4 +1,19 @@
 package labs.introtoprogramming.lab5.scene;
 
-public abstract class PointLight extends SceneObject {
+import labs.introtoprogramming.lab5.geometry.Vector3;
+
+public class PointLight extends Light {
+  public PointLight(Transform transform, double intensity) {
+    super(transform, intensity);
+  }
+
+  @Override
+  public double illuminate(Vector3 normal, double distance) {
+    return Math.max((intensity() * normal.dotProduct(getTransform().rotation().multiply(-1))) / (4 * Math.PI * Math.pow(distance, 2)), 0);
+  }
+
+  @Override
+  public double getMaxDist(Vector3 point) {
+    return point.distance(transform.position());
+  }
 }

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

@@ -13,7 +13,7 @@ public abstract class Scene {
 
   public abstract List<SceneObject> getSceneObjects();
 
-  public abstract List<PointLight> getLights();
+  public abstract List<Light> getLights();
 
   public abstract List<Controller> getControllers();
 

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

@@ -1,12 +1,17 @@
 package labs.introtoprogramming.lab5.scene;
 
+import java.awt.Color;
 import labs.introtoprogramming.lab5.geometry.Ray;
+import labs.introtoprogramming.lab5.geometry.Vector3;
 import labs.introtoprogramming.lab5.object.Box;
 
 public class SceneObject {
 
+  private static double DEFAULT_ALBEDO = 0.18;
+
   protected Transform transform;
   protected Mesh mesh;
+  protected double albedo = DEFAULT_ALBEDO;
 
   /**
    * Base class of scene objects.
@@ -39,7 +44,13 @@ public boolean intersect(Ray ray) {
     return false;
   }
 
+  public Vector3 getNormal(Vector3 hitPoint) { return Vector3.ZERO; }
+
   public Box getBoundary() {
     return null;
   }
+
+  public double albedo() {
+    return albedo;
+  }
 }

src/main/java/labs/introtoprogramming/lab5/scenes/DemoScene.java

@@ -1,18 +1,26 @@
 package labs.introtoprogramming.lab5.scenes;
 
+import java.awt.Color;
 import labs.introtoprogramming.lab5.geometry.Vector3;
 import labs.introtoprogramming.lab5.object.Box;
 import labs.introtoprogramming.lab5.object.Sphere;
 import labs.introtoprogramming.lab5.scene.BasicScene;
+import labs.introtoprogramming.lab5.scene.DistantLight;
+import labs.introtoprogramming.lab5.scene.PointLight;
 import labs.introtoprogramming.lab5.scene.Transform;
 
 public class DemoScene extends BasicScene {
 
   public DemoScene() {
+    Box other = new Box(new Transform(new Vector3(0, -6, 0)), 10);
+    Sphere sphere = new Sphere(new Transform(Vector3.FORWARD.multiply(-3)), 1);
+    sphere.getMesh().setColor(Color.RED);
     addSceneObjects(
-            new Sphere(new Transform(Vector3.FORWARD.multiply(-3)), 1),
-            new Box(new Transform(Vector3.FORWARD.multiply(-10)), 1),
-            new Box(new Transform(Vector3.RIGHT.multiply(5)), 1)
+            sphere,
+            new Box(new Transform(new Vector3(2, 2, -3)), 1),
+            other,
+            new DistantLight(new Transform(Vector3.ZERO, new Vector3(0, -1, 0)), 10)
+            //new PointLight(new Transform(new Vector3(0, 0, -1), new Vector3(0, -1, 0)), 1000)
     );
   }
 }