add math and image

src/test/java/eu/jonahbauer/raytracing/math/RayTest.java

@@ -0,0 +1,16 @@
+package eu.jonahbauer.raytracing.math;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class RayTest {
+
+    @Test
+    void at() {
+        var origin = new Vec3(0, 0, 0);
+        var direction = new Vec3(1, 2, 3);
+        var ray = new Ray(origin, direction);
+        assertEquals(new Vec3(5, 10, 15), ray.at(5));
+    }
+}

src/test/java/eu/jonahbauer/raytracing/math/Vec3Test.java

@@ -0,0 +1,61 @@
+package eu.jonahbauer.raytracing.math;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class Vec3Test {
+
+    @Test
+    void plus() {
+        var a = new Vec3(1, 2, 3);
+        var b = new Vec3(-1, 1, -2);
+        assertEquals(new Vec3(0, 3, 1), a.plus(b));
+    }
+
+    @Test
+    void minus() {
+        var a = new Vec3(1, 2, 3);
+        var b = new Vec3(-1, 1, -2);
+        assertEquals(new Vec3(2, 1, 5), a.minus(b));
+    }
+
+    @Test
+    void timesVec() {
+        var a = new Vec3(1, 2, 3);
+        var b = new Vec3(-1, 1, -2);
+        assertEquals(-5, a.times(b));
+    }
+
+    @Test
+    void timeScalar() {
+        var a = new Vec3(1, 2, 3);
+        var b = 2.5;
+        assertEquals(new Vec3(2.5, 5, 7.5), a.times(b));
+    }
+
+    @Test
+    void div() {
+        var a = new Vec3(1, 2, 3);
+        var b = 2;
+        assertEquals(new Vec3(0.5, 1, 1.5), a.div(b));
+    }
+
+    @Test
+    void squared() {
+        var a = new Vec3(1, 2, 3);
+        assertEquals(14, a.squared());
+    }
+
+    @Test
+    void length() {
+        var a = new Vec3(3, 4, 0);
+        assertEquals(5, a.length());
+    }
+
+    @Test
+    void unit() {
+        var a = new Vec3(3, 4, 0);
+        assertEquals(new Vec3(0.6, 0.8, 0), a.unit());
+    }
+}

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

@@ -0,0 +1,47 @@
+package eu.jonahbauer.raytracing.render;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Objects;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class ImageTest {
+
+    @Test
+    void test(@TempDir Path dir) throws IOException {
+        var image = new Image(256, 256);
+
+        for (var y = 0; y < image.height(); y++) {
+            for (var x = 0; x < image.width(); x++) {
+                var r = (double) x / (image.width() - 1);
+                var g = (double) y / (image.height() - 1);
+                var b = 0;
+
+                image.set(x, y, r, g, b);
+            }
+        }
+
+        System.out.println(dir);
+        ImageIO.write(image, dir.resolve("img.ppm"));
+
+        String expected;
+        String actual;
+
+        try (var in = Objects.requireNonNull(ImageTest.class.getResourceAsStream("simple_image.ppm"))) {
+            expected = new String(in.readAllBytes(), StandardCharsets.US_ASCII);
+        }
+
+        try (var in = Files.newInputStream(dir.resolve("img.ppm"))) {
+            actual = new String(in.readAllBytes(), StandardCharsets.US_ASCII);
+        }
+
+        assertEquals(expected, actual);
+    }
+
+}