Add Parallelepiped as a Solid

.idea/vcs.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="$PROJECT_DIR$" vcs="Git" />
+  </component>
+</project>

src/xyz/marsavic/gfxlab/graphics3d/raytracers/RayTracingTest.java

@@ -6,24 +6,29 @@ import xyz.marsavic.gfxlab.ColorFunctionT;
 import xyz.marsavic.gfxlab.Vec3;
 import xyz.marsavic.gfxlab.graphics3d.Hit;
 import xyz.marsavic.gfxlab.graphics3d.Ray;
-import xyz.marsavic.gfxlab.graphics3d.solids.Ball;
 import xyz.marsavic.gfxlab.graphics3d.solids.HalfSpace;
+import xyz.marsavic.gfxlab.graphics3d.solids.Parallelepiped;
+import xyz.marsavic.utils.Numeric;
 
 
 public class RayTracingTest implements ColorFunctionT {
 
-	Ball ball = Ball.cr(Vec3.xyz(0, 0, 2), 1);
+	// Ball ball = Ball.cr(Vec3.xyz(0, 0, 2), 1);
 	HalfSpace halfSpace = HalfSpace.pn(Vec3.xyz(0, -1, 0), Vec3.xyz(0, 1, 0));
-	
+	Parallelepiped parall1 = Parallelepiped.pabc(Vec3.xyz(-0.8, -0.5, 1.5),
+			Vec3.xyz(1, 0, 0), Vec3.xyz(1, 1, 0.5), Vec3.xyz(0, 0, 1));
+	Parallelepiped parall2 = Parallelepiped.pabc(Vec3.xyz(0.8, 0.0, 1.5),
+			Vec3.xyz(2, 0, 1), Vec3.xyz(1, 5, 0), Vec3.xyz(0, 0, 1));
 	@Override
 	public Color at(double t, Vector p) {
-		Ray ray = Ray.pq(Vec3.ZERO, Vec3.zp(1, p));
+		Ray ray = Ray.pq(Vec3.xyz(-Numeric.sinT(t), Numeric.sinT(t), 0), Vec3.zp(1, p));
 		
-		Hit hit1 = ball.firstHit(ray);
+		Hit hit1 = parall1.firstHit(ray);
 		Hit hit2 = halfSpace.firstHit(ray);
-		
-		double tMin = Math.min(Hit.t(hit1), Hit.t(hit2));
-		
+		Hit hit3 = parall2.firstHit(ray);
+
+		double tMin = Math.min(Hit.t(hit1), Math.min(Hit.t(hit2), Hit.t(hit3)));
+
 		return Color.gray(1.0 / (1.0 + tMin));
 	}
 	

src/xyz/marsavic/gfxlab/graphics3d/solids/Parallelepiped.java

@@ -0,0 +1,105 @@
+package xyz.marsavic.gfxlab.graphics3d.solids;
+
+import xyz.marsavic.gfxlab.Vec3;
+import xyz.marsavic.gfxlab.graphics3d.Hit;
+import xyz.marsavic.gfxlab.graphics3d.Ray;
+import xyz.marsavic.gfxlab.graphics3d.Solid;
+
+public class Parallelepiped implements Solid {
+
+    private final Vec3 p; // starting vertex
+
+    private final Vec3[][][] vertices;
+    HalfSpace [] sides;
+
+    private final Vec3 a, b, c;
+
+    private Parallelepiped(Vec3 point, Vec3 aEdge, Vec3 bEdge, Vec3 cEdge) {
+        this.p = point;
+        this.a = aEdge;
+        this.b = bEdge;
+        this.c = cEdge;
+
+        vertices = new Vec3[][][]
+                {{{p,       p.add(c)},        {p.add(b),        p.add(b).add(c)}},
+                {{p.add(a), p.add(a).add(c)}, {p.add(a).add(b), p.add(a).add(b).add(c)}}};
+        sides = new HalfSpace[6];
+        sides[0] = HalfSpace.pef(p, b, a);
+        sides[1] = HalfSpace.pef(p.add(c), a, b);
+        sides[2] = HalfSpace.pef(p, a, c);
+        sides[3] = HalfSpace.pef(p.add(b), c, a);
+        sides[4] = HalfSpace.pef(p, c, b);
+        sides[5] = HalfSpace.pef(p.add(a), b, c);
+    }
+
+
+    public static Parallelepiped pabc(Vec3 p, Vec3 a, Vec3 b, Vec3 c) {
+        return new Parallelepiped(p, a, b, c);
+    }
+
+    public Vec3 p() {
+        return p;
+    }
+
+    public Vec3 a() {
+        return a;
+    }
+
+    public Vec3 b() {
+        return b;
+    }
+
+    public Vec3 c() {
+        return c;
+    }
+
+    public Vec3[][][] vertices() {
+        return vertices.clone();
+    }
+
+    private static boolean pointOnParallelogram(Vec3 p, Vec3 e, Vec3 f) {
+        // we solve p as a linear combination of a*e+b*f, then check if this combination is in
+        // 0<=a<=1 and 0<=b<=1
+        double D = e.lengthSquared() * f.lengthSquared() - e.dot(f)*e.dot(f);
+        if (D == 0)
+            return false;
+        // System determinant
+        double Da = p.dot(e)*f.lengthSquared() - p.dot(f)*e.dot(f);
+        // a's determinant
+        double Db = e.lengthSquared()*p.dot(f) - e.dot(f)*p.dot(e);
+        double a = Da/D;
+        // a's determinant
+        double b = Db/D;
+        // b's determinant
+        return a >= 0 && a <= 1 && b >= 0 && b <= 1;
+    }
+
+
+    @Override
+    public Hit firstHit(Ray ray, double afterTime) {
+        Hit[] planeHits = new Hit[6];
+
+        for (int i = 0; i < 6; i++) {
+            planeHits[i] = sides[i].firstHit(ray, afterTime);
+            if (planeHits[i] == null) {
+                continue;
+            }
+            Vec3 rayPlaneIntersect = ray.at(planeHits[i].t());
+            if (!pointOnParallelogram(rayPlaneIntersect.sub(sides[i].p()), sides[i].e(), sides[i].f())) {
+                planeHits[i] = null;
+            }
+        }
+
+        double minT = Hit.t(null); // Positive infinity
+        int minI = 0;
+        for (int i = 0; i < 6; i++) {
+            if (Hit.t(planeHits[i]) < minT) {
+                minT = Hit.t(planeHits[i]);
+                minI = i;
+            }
+        }
+
+        return planeHits[minI];
+    }
+
+}

src/xyz/marsavic/gfxlab/gui/UtilsGL.java

@@ -149,7 +149,7 @@ public class UtilsGL {
 		} catch (Exception e) {
 			e.printStackTrace();
 		}
-		parallelism = p;
+		parallelism = 3;
 		pool = new ForkJoinPool(parallelism);
 	}