add texture support

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

@@ -1,7 +1,8 @@
 package eu.jonahbauer.raytracing;
 
 import eu.jonahbauer.raytracing.math.Vec3;
-import eu.jonahbauer.raytracing.render.Color;
+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.scene.Hittable;
@@ -61,7 +62,10 @@ public class Examples {
 
         var rng = new Random(1);
         var objects = new ArrayList<Hittable>();
-        objects.add(new Sphere(new Vec3(0, -1000, 0), 1000, new LambertianMaterial(new Color(0.5, 0.5, 0.5))));
+        objects.add(new Sphere(
+                new Vec3(0, -1000, 0), 1000,
+                new LambertianMaterial(new CheckerTexture(0.32, new Color(.2, .3, .1), new Color(.9, .9, .9)))
+        ));
 
         for (int a = -11; a < 11; a++) {
             for (int b = -11; b < 11; b++) {

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

@@ -1,6 +1,6 @@
 package eu.jonahbauer.raytracing.render.canvas;
 
-import eu.jonahbauer.raytracing.render.Color;
+import eu.jonahbauer.raytracing.render.texture.Color;
 import org.jetbrains.annotations.NotNull;
 
 import java.util.function.Function;

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

@@ -1,6 +1,6 @@
 package eu.jonahbauer.raytracing.render.canvas;
 
-import eu.jonahbauer.raytracing.render.Color;
+import eu.jonahbauer.raytracing.render.texture.Color;
 import org.jetbrains.annotations.NotNull;
 
 import java.util.Objects;

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

@@ -1,6 +1,6 @@
 package eu.jonahbauer.raytracing.render.canvas;
 
-import eu.jonahbauer.raytracing.render.Color;
+import eu.jonahbauer.raytracing.render.texture.Color;
 import org.jetbrains.annotations.NotNull;
 
 import javax.swing.*;

src/main/java/eu/jonahbauer/raytracing/render/material/DielectricMaterial.java

@@ -2,7 +2,8 @@ package eu.jonahbauer.raytracing.render.material;
 
 import eu.jonahbauer.raytracing.math.Ray;
 import eu.jonahbauer.raytracing.math.Vec3;
-import eu.jonahbauer.raytracing.render.Color;
+import eu.jonahbauer.raytracing.render.texture.Color;
+import eu.jonahbauer.raytracing.render.texture.Texture;
 import eu.jonahbauer.raytracing.scene.HitResult;
 import org.jetbrains.annotations.NotNull;
 
@@ -10,13 +11,13 @@ import java.util.Objects;
 import java.util.Optional;
 import java.util.random.RandomGenerator;
 
-public record DielectricMaterial(double refractionIndex, @NotNull Color albedo) implements Material {
+public record DielectricMaterial(double refractionIndex, @NotNull Texture texture) implements Material {
     public DielectricMaterial(double refractionIndex) {
         this(refractionIndex, Color.WHITE);
     }
 
     public DielectricMaterial {
-        Objects.requireNonNull(albedo, "albedo");
+        Objects.requireNonNull(texture, "texture");
     }
 
     @Override
@@ -30,7 +31,8 @@ public record DielectricMaterial(double refractionIndex, @NotNull Color albedo)
         var newDirection = (reflect ? Optional.<Vec3>empty() : Vec3.refract(ray.direction(), hit.normal(), ri))
                 .orElseGet(() -> Vec3.reflect(ray.direction(), hit.normal()));
 
-        return Optional.of(new ScatterResult(new Ray(hit.position(), newDirection), albedo));
+        var attenuation = texture.get(hit);
+        return Optional.of(new ScatterResult(new Ray(hit.position(), newDirection), attenuation));
     }
 
     private double reflectance(double cos) {

src/main/java/eu/jonahbauer/raytracing/render/material/DiffuseLight.java

@@ -1,14 +1,15 @@
 package eu.jonahbauer.raytracing.render.material;
 
 import eu.jonahbauer.raytracing.math.Ray;
-import eu.jonahbauer.raytracing.render.Color;
+import eu.jonahbauer.raytracing.render.texture.Color;
+import eu.jonahbauer.raytracing.render.texture.Texture;
 import eu.jonahbauer.raytracing.scene.HitResult;
 import org.jetbrains.annotations.NotNull;
 
 import java.util.Optional;
 import java.util.random.RandomGenerator;
 
-public record DiffuseLight(@NotNull Color emit) implements Material {
+public record DiffuseLight(@NotNull Texture texture) implements Material {
     @Override
     public @NotNull Optional<ScatterResult> scatter(@NotNull Ray ray, @NotNull HitResult hit, @NotNull RandomGenerator random) {
         return Optional.empty();
@@ -16,6 +17,6 @@ public record DiffuseLight(@NotNull Color emit) implements Material {
 
     @Override
     public @NotNull Color emitted(@NotNull HitResult hit) {
-        return emit;
+        return texture.get(hit);
     }
 }

src/main/java/eu/jonahbauer/raytracing/render/material/IsotropicMaterial.java

@@ -2,7 +2,7 @@ package eu.jonahbauer.raytracing.render.material;
 
 import eu.jonahbauer.raytracing.math.Ray;
 import eu.jonahbauer.raytracing.math.Vec3;
-import eu.jonahbauer.raytracing.render.Color;
+import eu.jonahbauer.raytracing.render.texture.Color;
 import eu.jonahbauer.raytracing.scene.HitResult;
 import org.jetbrains.annotations.NotNull;
 

src/main/java/eu/jonahbauer/raytracing/render/material/LambertianMaterial.java

@@ -2,7 +2,7 @@ package eu.jonahbauer.raytracing.render.material;
 
 import eu.jonahbauer.raytracing.math.Ray;
 import eu.jonahbauer.raytracing.math.Vec3;
-import eu.jonahbauer.raytracing.render.Color;
+import eu.jonahbauer.raytracing.render.texture.Texture;
 import eu.jonahbauer.raytracing.scene.HitResult;
 import org.jetbrains.annotations.NotNull;
 
@@ -10,9 +10,9 @@ import java.util.Objects;
 import java.util.Optional;
 import java.util.random.RandomGenerator;
 
-public record LambertianMaterial(@NotNull Color albedo) implements Material {
+public record LambertianMaterial(@NotNull Texture texture) implements Material {
     public LambertianMaterial {
-        Objects.requireNonNull(albedo, "albedo");
+        Objects.requireNonNull(texture, "texture");
     }
 
     @Override
@@ -20,7 +20,8 @@ public record LambertianMaterial(@NotNull Color albedo) implements Material {
         var newDirection = hit.normal().plus(Vec3.random(random, true));
         if (newDirection.isNearZero()) newDirection = hit.normal();
 
+        var attenuation = texture.get(hit);
         var scattered = new Ray(hit.position(), newDirection);
-        return Optional.of(new ScatterResult(scattered, albedo));
+        return Optional.of(new ScatterResult(scattered, attenuation));
     }
 }

src/main/java/eu/jonahbauer/raytracing/render/material/Material.java

@@ -1,7 +1,7 @@
 package eu.jonahbauer.raytracing.render.material;
 
 import eu.jonahbauer.raytracing.math.Ray;
-import eu.jonahbauer.raytracing.render.Color;
+import eu.jonahbauer.raytracing.render.texture.Color;
 import eu.jonahbauer.raytracing.scene.HitResult;
 import org.jetbrains.annotations.NotNull;
 

src/main/java/eu/jonahbauer/raytracing/render/material/MetallicMaterial.java

@@ -2,7 +2,7 @@ package eu.jonahbauer.raytracing.render.material;
 
 import eu.jonahbauer.raytracing.math.Ray;
 import eu.jonahbauer.raytracing.math.Vec3;
-import eu.jonahbauer.raytracing.render.Color;
+import eu.jonahbauer.raytracing.render.texture.Texture;
 import eu.jonahbauer.raytracing.scene.HitResult;
 import org.jetbrains.annotations.NotNull;
 
@@ -10,14 +10,14 @@ import java.util.Objects;
 import java.util.Optional;
 import java.util.random.RandomGenerator;
 
-public record MetallicMaterial(@NotNull Color albedo, double fuzz) implements Material {
+public record MetallicMaterial(@NotNull Texture texture, double fuzz) implements Material {
 
-    public MetallicMaterial(@NotNull Color albedo) {
-        this(albedo, 0);
+    public MetallicMaterial(@NotNull Texture texture) {
+        this(texture, 0);
     }
 
     public MetallicMaterial {
-        Objects.requireNonNull(albedo, "albedo");
+        Objects.requireNonNull(texture, "texture");
         if (fuzz < 0 || !Double.isFinite(fuzz)) throw new IllegalArgumentException("fuzz must be non-negative");
     }
 
@@ -27,6 +27,7 @@ public record MetallicMaterial(@NotNull Color albedo, double fuzz) implements Ma
         if (fuzz > 0) {
             newDirection = newDirection.unit().plus(Vec3.random(random, true).times(fuzz));
         }
-        return Optional.of(new ScatterResult(new Ray(hit.position(), newDirection), albedo));
+        var attenuation = texture.get(hit);
+        return Optional.of(new ScatterResult(new Ray(hit.position(), newDirection), attenuation));
     }
 }

src/main/java/eu/jonahbauer/raytracing/render/renderer/SimpleRenderer.java

@@ -2,7 +2,7 @@ package eu.jonahbauer.raytracing.render.renderer;
 
 import eu.jonahbauer.raytracing.math.Range;
 import eu.jonahbauer.raytracing.math.Ray;
-import eu.jonahbauer.raytracing.render.Color;
+import eu.jonahbauer.raytracing.render.texture.Color;
 import eu.jonahbauer.raytracing.render.camera.Camera;
 import eu.jonahbauer.raytracing.render.canvas.Canvas;
 import eu.jonahbauer.raytracing.scene.Scene;

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

@@ -0,0 +1,17 @@
+package eu.jonahbauer.raytracing.render.texture;
+
+import eu.jonahbauer.raytracing.math.Vec3;
+import org.jetbrains.annotations.NotNull;
+
+public record CheckerTexture(double scale, @NotNull Texture even, @NotNull Texture odd) implements Texture {
+
+
+    @Override
+    public @NotNull Color get(double u, double v, @NotNull Vec3 p) {
+        var x = (int) Math.floor(p.x() / scale);
+        var y = (int) Math.floor(p.y() / scale);
+        var z = (int) Math.floor(p.z() / scale);
+        var even = (x + y + z) % 2 == 0;
+        return even ? even().get(u, v, p) : odd().get(u, v, p);
+    }
+}

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

@@ -1,10 +1,11 @@
-package eu.jonahbauer.raytracing.render;
+package eu.jonahbauer.raytracing.render.texture;
 
+import eu.jonahbauer.raytracing.math.Vec3;
 import org.jetbrains.annotations.NotNull;
 
 import java.util.Random;
 
-public record Color(double r, double g, double b) {
+public record Color(double r, double g, double b) implements Texture {
     public static final @NotNull Color BLACK = new Color(0.0, 0.0, 0.0);
     public static final @NotNull Color WHITE = new Color(1.0, 1.0, 1.0);
     public static final @NotNull Color RED = new Color(1.0, 0.0, 0.0);
@@ -68,7 +69,9 @@ public record Color(double r, double g, double b) {
         }
     }
 
-    public Color {}
+    public Color(int rgb) {
+        this((rgb >> 16) & 0xFF, (rgb >> 8) & 0xFF, rgb & 0xFF);
+    }
     
     public Color(int red, int green, int blue) {
         this(red / 255f, green / 255f, blue / 255f);
@@ -86,7 +89,12 @@ public record Color(double r, double g, double b) {
         return toInt(b);
     }
 
+    @Override
+    public @NotNull Color get(double u, double v, @NotNull Vec3 p) {
+        return this;
+    }
+
     private static int toInt(double value) {
-        return Math.max(0, Math.min(255, (int) (255.99 * value)));
+        return Math.clamp((int) (255.99 * value), 0, 255);
     }
 }

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

@@ -0,0 +1,13 @@
+package eu.jonahbauer.raytracing.render.texture;
+
+import eu.jonahbauer.raytracing.math.Vec3;
+import eu.jonahbauer.raytracing.scene.HitResult;
+import org.jetbrains.annotations.NotNull;
+
+public interface Texture {
+    default @NotNull Color get(@NotNull HitResult hit) {
+        return get(hit.u(), hit.v(), hit.position());
+    }
+
+    @NotNull Color get(double u, double v, @NotNull Vec3 p);
+}

src/main/java/eu/jonahbauer/raytracing/scene/HitResult.java

@@ -7,17 +7,18 @@ import org.jetbrains.annotations.NotNull;
 import java.util.Objects;
 
 public record HitResult(
-        double t,
-        @NotNull Vec3 position,
-        @NotNull Vec3 normal,
-        @NotNull Material material,
-        boolean frontFace
+        double t, @NotNull Vec3 position, @NotNull Vec3 normal,
+        @NotNull Material material, double u, double v, boolean frontFace
 ) implements Comparable<HitResult> {
     public HitResult {
         Objects.requireNonNull(position, "position");
         normal = normal.unit();
     }
 
+    public @NotNull HitResult withPositionAndNormal(@NotNull Vec3 position, @NotNull Vec3 normal) {
+        return new HitResult(t, position, normal, material, u, v, frontFace);
+    }
+
     @Override
     public int compareTo(@NotNull HitResult o) {
         return Double.compare(t, o.t);

src/main/java/eu/jonahbauer/raytracing/scene/Scene.java

@@ -2,7 +2,7 @@ package eu.jonahbauer.raytracing.scene;
 
 import eu.jonahbauer.raytracing.math.AABB;
 import eu.jonahbauer.raytracing.math.Ray;
-import eu.jonahbauer.raytracing.render.Color;
+import eu.jonahbauer.raytracing.render.texture.Color;
 import eu.jonahbauer.raytracing.scene.util.HittableBinaryTree;
 import eu.jonahbauer.raytracing.scene.util.HittableCollection;
 import org.jetbrains.annotations.NotNull;

src/main/java/eu/jonahbauer/raytracing/scene/SkyBox.java

@@ -1,7 +1,7 @@
 package eu.jonahbauer.raytracing.scene;
 
 import eu.jonahbauer.raytracing.math.Ray;
-import eu.jonahbauer.raytracing.render.Color;
+import eu.jonahbauer.raytracing.render.texture.Color;
 import org.jetbrains.annotations.NotNull;
 
 @FunctionalInterface

src/main/java/eu/jonahbauer/raytracing/scene/hittable2d/Hittable2D.java

@@ -51,7 +51,10 @@ public abstract class Hittable2D implements Hittable {
         if (!isInterior(alpha, beta)) return Optional.empty();
 
         var frontFace = denominator < 0;
-        return Optional.of(new HitResult(t, position, frontFace ? normal : normal.neg(), material, frontFace));
+        return Optional.of(new HitResult(
+                t, position, frontFace ? normal : normal.neg(),
+                material, alpha, beta, frontFace
+        ));
     }
 
     protected abstract boolean isInterior(double alpha, double beta);

src/main/java/eu/jonahbauer/raytracing/scene/hittable3d/ConstantMedium.java

@@ -32,7 +32,7 @@ public record ConstantMedium(@NotNull Hittable boundary, double density, @NotNul
         if (hitDistance > distance) return Optional.empty();
 
         var t = tmin + hitDistance / length;
-        return Optional.of(new HitResult(t, ray.at(t), Vec3.UNIT_X, material, true)); // arbitrary normal and frontFace
+        return Optional.of(new HitResult(t, ray.at(t), Vec3.UNIT_X, material, 0, 0, true)); // arbitrary normal and frontFace
     }
 
     @Override

src/main/java/eu/jonahbauer/raytracing/scene/hittable3d/Sphere.java

@@ -49,9 +49,19 @@ public final class Sphere implements Hittable {
         if (!range.surrounds(t)) return Optional.empty();
 
         var position = ray.at(t);
-        var normal = position.minus(center);
+        var normal = position.minus(center).div(radius);
         var frontFace = normal.times(ray.direction()) < 0;
-        return Optional.of(new HitResult(t, position, frontFace ? normal : normal.times(-1), material, frontFace));
+
+        var theta = Math.acos(- normal.y());
+        var phi = Math.atan2(- normal.z(), normal.x()) + Math.PI;
+
+        var u = phi / (2 * Math.PI);
+        var v = theta / Math.PI;
+
+        return Optional.of(new HitResult(
+                t, position, frontFace ? normal : normal.neg(),
+                material, u, v, frontFace
+        ));
     }
 
     @Override

src/main/java/eu/jonahbauer/raytracing/scene/transform/RotateY.java

@@ -79,7 +79,7 @@ public final class RotateY extends Transform {
                 -sin * normal.x() + cos * normal.z()
         );
 
-        return new HitResult(result.t(), newPosition, newNormal, result.material(), result.frontFace());
+        return result.withPositionAndNormal(newPosition, newNormal);
     }
 
     @Override

src/main/java/eu/jonahbauer/raytracing/scene/transform/Translate.java

@@ -29,13 +29,7 @@ public final class Translate extends Transform {
 
     @Override
     protected @NotNull HitResult transform(@NotNull HitResult result) {
-        return new HitResult(
-                result.t(),
-                result.position().plus(offset),
-                result.normal(),
-                result.material(),
-                result.frontFace()
-        );
+        return result.withPositionAndNormal(result.position().plus(offset), result.normal());
     }
 
     @Override

src/test/java/eu/jonahbauer/raytracing/render/canvas/ImageTest.java

@@ -1,6 +1,6 @@
 package eu.jonahbauer.raytracing.render.canvas;
 
-import eu.jonahbauer.raytracing.render.Color;
+import eu.jonahbauer.raytracing.render.texture.Color;
 import eu.jonahbauer.raytracing.render.ImageFormat;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;

src/test/java/eu/jonahbauer/raytracing/scene/hittable3d/SphereTest.java

@@ -3,7 +3,7 @@ package eu.jonahbauer.raytracing.scene.hittable3d;
 import eu.jonahbauer.raytracing.math.Range;
 import eu.jonahbauer.raytracing.math.Ray;
 import eu.jonahbauer.raytracing.math.Vec3;
-import eu.jonahbauer.raytracing.render.Color;
+import eu.jonahbauer.raytracing.render.texture.Color;
 import eu.jonahbauer.raytracing.render.material.LambertianMaterial;
 import org.junit.jupiter.api.Test;