add cornell box

src/main/java/eu/jonahbauer/raytracing/Main.java

@@ -18,12 +18,11 @@ import org.jetbrains.annotations.NotNull;
 import java.io.IOException;
 import java.nio.file.Path;
 import java.util.ArrayList;
-import java.util.List;
 import java.util.Random;
 
 public class Main {
     public static void main(String[] args) throws IOException {
-        var example = getLight();
+        var example = getCornellBox();
         var scene = example.scene();
         var camera = example.camera();
 
@@ -125,6 +124,32 @@ public class Main {
         );
     }
 
+    private static @NotNull Example getCornellBox() {
+        var red = new LambertianMaterial(new Color(.65, .05, .05));
+        var white = new LambertianMaterial(new Color(.73, .73, .73));
+        var green = new LambertianMaterial(new Color(.12, .45, .15));
+        var light = new DiffuseLight(new Color(15.0, 15.0, 15.0));
+
+        return new Example(
+                new Scene(
+                        new Parallelogram(new Vec3(555, 0, 0), new Vec3(0, 555, 0), new Vec3(0, 0, 555), green),
+                        new Parallelogram(new Vec3(0, 0, 0), new Vec3(0, 555, 0), new Vec3(0, 0, 555), red),
+                        new Parallelogram(new Vec3(343, 554, 332), new Vec3(-130, 0, 0), new Vec3(0, 0, -105), light),
+                        new Parallelogram(new Vec3(0, 0, 0), new Vec3(555, 0 ,0), new Vec3(0, 0, 555), white),
+                        new Parallelogram(new Vec3(555, 555, 555), new Vec3(-555, 0 ,0), new Vec3(0, 0, -555), white),
+                        new Parallelogram(new Vec3(0, 0, 555), new Vec3(555, 0 ,0), new Vec3(0, 555, 0), white),
+                        Hittables.box(new Vec3(130, 0, 65), new Vec3(295, 165, 230), white),
+                        Hittables.box(new Vec3(265, 0, 295), new Vec3(430, 330, 460), white)
+                ),
+                SimpleCamera.builder()
+                        .withImage(600, 600)
+                        .withFieldOfView(Math.toRadians(40))
+                        .withPosition(new Vec3(278, 278, -800))
+                        .withTarget(new Vec3(278, 278, 0))
+                        .build()
+        );
+    }
+
     private static @NotNull Scene getSimpleScene() {
         return new Scene(
                 getSkyBox(),

src/main/java/eu/jonahbauer/raytracing/scene/util/Hittables.java

@@ -0,0 +1,35 @@
+package eu.jonahbauer.raytracing.scene.util;
+
+import eu.jonahbauer.raytracing.math.Vec3;
+import eu.jonahbauer.raytracing.render.material.Material;
+import eu.jonahbauer.raytracing.scene.Hittable;
+import eu.jonahbauer.raytracing.scene.hittable2d.Parallelogram;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.ArrayList;
+
+public final class Hittables {
+    private Hittables() {
+        throw new UnsupportedOperationException();
+    }
+
+    public static @NotNull Hittable box(@NotNull Vec3 a, @NotNull Vec3 b, @NotNull Material material) {
+        var sides = new ArrayList<Hittable>();
+
+        var min = Vec3.min(a, b);
+        var max = Vec3.max(a, b);
+
+        var dx = new Vec3(max.x() - min.x(), 0, 0);
+        var dy = new Vec3(0, max.y() - min.y(), 0);
+        var dz = new Vec3(0, 0, max.z() - min.z());
+
+        sides.add(new Parallelogram(new Vec3(min.x(), min.y(), max.z()), dx, dy, material)); // front
+        sides.add(new Parallelogram(new Vec3(max.x(), min.y(), max.z()), dz.neg(), dy, material)); // right
+        sides.add(new Parallelogram(new Vec3(max.x(), min.y(), min.z()), dx.neg(), dy, material)); // back
+        sides.add(new Parallelogram(new Vec3(min.x(), min.y(), min.z()), dz, dy, material)); // left
+        sides.add(new Parallelogram(new Vec3(min.x(), max.y(), max.z()), dx, dz.neg(), material)); // top
+        sides.add(new Parallelogram(new Vec3(min.x(), min.y(), min.z()), dx, dz, material)); // bottom
+
+        return new HittableList(sides);
+    }
+}