add image texture

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

@@ -5,6 +5,7 @@ import eu.jonahbauer.raytracing.render.texture.CheckerTexture;
 import eu.jonahbauer.raytracing.render.texture.Color;
 import eu.jonahbauer.raytracing.render.camera.SimpleCamera;
 import eu.jonahbauer.raytracing.render.material.*;
+import eu.jonahbauer.raytracing.render.texture.ImageTexture;
 import eu.jonahbauer.raytracing.scene.Hittable;
 import eu.jonahbauer.raytracing.scene.Scene;
 import eu.jonahbauer.raytracing.scene.SkyBox;
@@ -32,6 +33,7 @@ public class Examples {
         register("CORNELL", Examples::getCornellBox);
         register("CORNELL_SMOKE", Examples::getCornellBoxSmoke);
         register("DIAGRAMM", Examples::getDiagramm);
+        register("EARTH", Examples::getEarth);
     }
 
     public static @NotNull IntFunction<Example> getByName(@NotNull String name) {
@@ -255,6 +257,23 @@ public class Examples {
         );
     }
 
+    public static @NotNull Example getEarth(int height) {
+        if (height <= 0) height = 450;
+
+        return new Example(
+                new Scene(
+                        getSkyBox(),
+                        new Sphere(Vec3.ZERO, 2, new LambertianMaterial(new ImageTexture("/earthmap.jpg")))
+                ),
+                SimpleCamera.builder()
+                        .withImage(height * 16 / 9, height)
+                        .withFieldOfView(Math.toRadians(20))
+                        .withPosition(new Vec3(12, 0, 0))
+                        .withTarget(Vec3.ZERO)
+                        .build()
+        );
+    }
+
     private static @NotNull SkyBox getSkyBox() {
         return SkyBox.gradient(new Color(0.5, 0.7, 1.0), Color.WHITE);
     }

src/main/java/eu/jonahbauer/raytracing/render/canvas/Image.java

@@ -3,6 +3,7 @@ package eu.jonahbauer.raytracing.render.canvas;
 import eu.jonahbauer.raytracing.render.texture.Color;
 import org.jetbrains.annotations.NotNull;
 
+import java.awt.image.BufferedImage;
 import java.util.Objects;
 
 public final class Image implements Canvas {
@@ -21,6 +22,16 @@ public final class Image implements Canvas {
         this.data = new Color[height][width];
     }
 
+    public Image(@NotNull BufferedImage image) {
+        this(image.getWidth(), image.getHeight());
+
+        for (int y = 0; y < height; y++) {
+            for (int x = 0; x < width; x++) {
+                this.data[y][x] = new Color(image.getRGB(x, y));
+            }
+        }
+    }
+
     @Override
     public int getWidth() {
         return width;

src/main/java/eu/jonahbauer/raytracing/render/texture/ImageTexture.java

@@ -0,0 +1,43 @@
+package eu.jonahbauer.raytracing.render.texture;
+
+import eu.jonahbauer.raytracing.math.Vec3;
+import eu.jonahbauer.raytracing.render.canvas.Image;
+import org.jetbrains.annotations.NotNull;
+
+import javax.imageio.ImageIO;
+import java.awt.image.BufferedImage;
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.util.Objects;
+
+public record ImageTexture(@NotNull Image image) implements Texture {
+
+    public ImageTexture {
+        Objects.requireNonNull(image, "image");
+    }
+
+    public ImageTexture(@NotNull BufferedImage image) {
+        this(new Image(image));
+    }
+
+    public ImageTexture(@NotNull String path) {
+        this(read(path));
+    }
+
+    private static @NotNull BufferedImage read(@NotNull String path) {
+        try (var in = Objects.requireNonNull(ImageTexture.class.getResourceAsStream(path))) {
+            return ImageIO.read(in);
+        } catch (IOException ex) {
+            throw new UncheckedIOException(ex);
+        }
+    }
+
+    @Override
+    public @NotNull Color get(double u, double v, @NotNull Vec3 p) {
+        u = Math.clamp(u, 0, 1);
+        v = 1 - Math.clamp(v, 0, 1);
+        int x = (int) (u * (image.getWidth() - 1));
+        int y = (int) (v * (image.getHeight() - 1));
+        return image.get(x, y);
+    }
+}