Air Drag merged.

5 files changed, 223 insertions, 7 deletions

diff --git a/src/alden/CollidableObject.java b/src/alden/CollidableObject.java
index eb3ff6a..236b731 100644
--- a/src/alden/CollidableObject.java
+++ b/src/alden/CollidableObject.java
@@ -103,7 +103,7 @@ public abstract class CollidableObject {
 		clearCaches();

 	}

 

-	protected ArrayList<Vector3f> getVertices() {

+	public ArrayList<Vector3f> getVertices() {

 		if (vertexCache == null)

 			vertexCache = CollisionDetector.extractVertices(node);

 		return vertexCache;

diff --git a/src/tesseract/TesseractUI.java b/src/tesseract/TesseractUI.java
index 882f6a8..9fd91b9 100644
--- a/src/tesseract/TesseractUI.java
+++ b/src/tesseract/TesseractUI.java
@@ -27,6 +27,7 @@ import javax.vecmath.Point3d;
 import javax.vecmath.Point3f;
 import javax.vecmath.Vector3f;
 
+import tesseract.forces.AirDrag;
 import tesseract.forces.CircularXY;
 import tesseract.forces.CircularXZ;
 import tesseract.forces.Force;
@@ -40,8 +41,8 @@ import tesseract.menuitems.IcosahedronMenuItem;
 import tesseract.menuitems.ParticleEmitterMenuItem;
 import tesseract.menuitems.ParticleMenuItem;
 import tesseract.menuitems.PlanarPolygonMenuItem;
+import tesseract.objects.Box;
 import tesseract.objects.ChainLink2;
-import tesseract.objects.Circle;
 import tesseract.objects.PhysicalObject;
 
 import com.sun.j3d.utils.picking.PickCanvas;
@@ -147,10 +148,16 @@ public class TesseractUI extends JFrame {
 		// TODO: REMOVE TEST CODE
 		
 		// Lookie! Linked chainlinks!
-		myWorld.addObject(new ChainLink2(new Vector3f(0.15f, 0, 0), 1));
+		//myWorld.addObject(new ChainLink2(new Vector3f(0.15f, 0, 0), 1));
 		ChainLink2 o = new ChainLink2(new Vector3f(), 1);
 		o.setRotation();
-		myWorld.addObject(o);
+		
+		myWorld.addForce(new AirDrag());
+		
+		myWorld.addObject(new Box(0.18f, 0.1f, 0.25f, new Vector3f(0.1f, -0.10f, 0)));
+		myWorld.addObject(new Box(0.18f, 0.25f, 0.1f, new Vector3f(-0.1f, 0, 0)));
+		
+		//myWorld.addObject(o);
 	}
 	
 	/**
diff --git a/src/tesseract/forces/AirDrag.java b/src/tesseract/forces/AirDrag.java
new file mode 100644
index 0000000..c27ec7e
--- /dev/null
+++ b/src/tesseract/forces/AirDrag.java
@@ -0,0 +1,193 @@
+package tesseract.forces;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+
+import javax.media.j3d.Transform3D;
+import javax.vecmath.Quat4f;
+import javax.vecmath.Vector2f;
+import javax.vecmath.Vector3f;
+
+import tesseract.objects.PhysicalObject;
+
+public class AirDrag extends Force {
+
+	private static final float COEFFICIENT = 20f;
+
+
+	@Override
+	protected Vector3f calculateForce(PhysicalObject obj) {
+		if (obj.isNodeNull() || obj.getVelocity().length() == 0) {
+			return new Vector3f();
+		}
+		
+		Vector3f v = new Vector3f(obj.getVelocity());
+		
+		Vector3f p = new Vector3f(obj.getPosition());
+		p.negate();
+		
+		Vector3f c = new Vector3f();
+		c.sub(new Vector3f(0, 1, 0), v);
+		
+		Quat4f r = new Quat4f(c.x, c.y, c.z, 0);
+		r.normalize();
+		
+		
+		Vector3f com = new Vector3f(-obj.getCenterOfMass().x, -obj.getCenterOfMass().y, -obj.getCenterOfMass().z);
+		com.negate();
+		
+		Transform3D tmp = new Transform3D();
+		tmp.setTranslation(com);
+		Transform3D tmp2 = new Transform3D();
+		tmp2.setRotation(r);
+		com.negate();
+		com.add(p);
+		tmp2.setTranslation(com);
+		tmp2.mul(tmp);
+		
+		ArrayList<Vector3f> vertices = obj.getVertices();
+		ArrayList<Vector2f> points = new ArrayList<Vector2f>(); 
+		
+		for (Vector3f point : vertices) {
+			tmp2.transform(point);
+			Vector2f newPoint = new Vector2f(point.x, point.z);
+			
+			// Place min y at front of arraylist if it's the minimum
+			if (points.size() == 0) {
+				points.add(newPoint);
+				
+			} else if (newPoint.y < points.get(0).y
+					|| (newPoint.y == points.get(0).y 
+							&& newPoint.x < points.get(0).x)) {
+				Vector2f oldPoint = points.get(0);
+				points.set(0, newPoint);
+				points.add(oldPoint);
+				
+			} else {
+				points.add(newPoint);
+			}
+		}
+		
+		List<Vector2f> hull = convexHull(points);
+		
+		float surfaceArea = areaOfHull(hull);
+		
+		float force = 0.5f * v.length() * COEFFICIENT * surfaceArea; 
+		
+		System.out.println(v.length());
+		System.out.println(force);
+		
+		v.normalize();
+		v.scale(-force);
+		
+		System.out.println(v);
+		
+		return v;
+		
+	}
+	
+	public static void main(String[] args) {
+		AirDrag ad = new AirDrag();
+		
+		ArrayList<Vector2f> points = new ArrayList<Vector2f>();
+		
+		/*points.add(new Vector2f(2, 1));
+		points.add(new Vector2f(2, 3));
+		points.add(new Vector2f(3, 4.5f));
+		points.add(new Vector2f(4, 2));
+		points.add(new Vector2f(4, 7));
+		points.add(new Vector2f(1, 2));
+		points.add(new Vector2f(1, 5));
+		points.add(new Vector2f(1.5f, 7));*/
+		
+		points.add(new Vector2f(0, 0));
+		points.add(new Vector2f(0, 3));
+		points.add(new Vector2f(3, 3));
+		points.add(new Vector2f(3, 0));
+		points.add(new Vector2f(1, 2));
+		points.add(new Vector2f(0, 1));
+		
+		List<Vector2f> newPoints = ad.convexHull(points);
+		System.out.println(newPoints);
+		
+		System.out.println(ad.areaOfHull(newPoints));
+	}
+	
+	private float areaOfHull(final List<Vector2f> hull) {
+		float area = 0;
+		Vector2f p = hull.get(0);
+		
+		for (int i = 2; i < hull.size(); i++) {
+			// Area of triangle p0 - p(i-1) - p(i)
+			Vector2f ab = new Vector2f();
+			Vector2f ac = new Vector2f();
+			
+			ab.sub(hull.get(i-1), p);
+			ac.sub(hull.get(i), p);
+			
+			area += 0.5f * (ab.x * ac.y - ac.x * ab.y);
+		}
+		
+		return area;
+	}
+	
+	private List<Vector2f> convexHull(final ArrayList<Vector2f> points) {
+		Collections.sort(points, new Vector2fAngleCompare(points.get(0)));
+		
+		points.set(0, points.get(points.size() - 1));
+		
+		int m = 2;
+		for (int i = 3; i < points.size(); i++) {
+			try {
+			while (i < points.size() - 1 && ccw(points.get(m - 1), points.get(m), points.get(i)) <= 0) {
+				if (m == 2) {
+					final Vector2f vec = points.get(m);
+					points.set(m, points.get(i));
+					points.set(i, vec);
+					i++;
+					
+				} else {
+					m--;
+				}
+			}
+			} catch (Exception e) {
+				System.out.println(e);
+			}
+			
+			m++;
+			
+			final Vector2f vec = points.get(m);
+			points.set(m, points.get(i));
+			points.set(i, vec);
+		}
+		
+		return points.subList(0, m+1);
+	}
+	
+	private float ccw(final Vector2f v1, final Vector2f v2, final Vector2f v3) {
+		return (v2.x - v1.x) * (v3.y - v1.y)- (v2.y - v1.y) * (v3.x - v1.x);  
+	}
+	
+
+	private class Vector2fAngleCompare implements Comparator<Vector2f> {
+		Vector2f base;
+		
+		public Vector2fAngleCompare(final Vector2f theBase) {
+			base = theBase;
+		}
+		
+		
+		public int compare(Vector2f o1, Vector2f o2) {
+			return (int) Math.signum(vecAngle(o1) - vecAngle(o2));
+		}	
+		
+		private float vecAngle(final Vector2f vector) {
+			final Vector2f v = new Vector2f();
+			v.sub(vector, base);
+			
+			return v.y / (v.x * v.x + v.y * v.y);
+		}
+	}
+}
diff --git a/src/tesseract/menuitems/IcosahedronMenuItem.java b/src/tesseract/menuitems/IcosahedronMenuItem.java
index c6b5bf1..9d4f9cb 100644
--- a/src/tesseract/menuitems/IcosahedronMenuItem.java
+++ b/src/tesseract/menuitems/IcosahedronMenuItem.java
@@ -54,7 +54,7 @@ public class IcosahedronMenuItem extends TesseractMenuItem {
 		defaultButton.addActionListener(new ActionListener() {

 			public void actionPerformed(final ActionEvent e) {

 				if (defaultButton.isSelected()) {

-					myWorld.addObject(new Icosahedron(getDefaultPosition(), 10, getDefaultRadius()));

+					myWorld.addObject(new Icosahedron(getDefaultPosition(), 1, getDefaultRadius()));

 					params.dispose();

 				}

 			}

diff --git a/src/tesseract/objects/PhysicalObject.java b/src/tesseract/objects/PhysicalObject.java
index fa69e8a..cdfca54 100644
--- a/src/tesseract/objects/PhysicalObject.java
+++ b/src/tesseract/objects/PhysicalObject.java
@@ -66,12 +66,12 @@ public class PhysicalObject extends CollidableObject {
 				shape.setCapability(Node.ALLOW_LOCAL_TO_VWORLD_READ);
 				shape.setCapability(Node.ALLOW_LOCAL_TO_VWORLD_READ);
 
-				for (int i = 0; i < shape.numGeometries(); i++) {
+				/*for (int i = 0; i < shape.numGeometries(); i++) {
 					shape.getGeometry(i).setCapability(
 							GeometryArray.ALLOW_COUNT_READ);
 					shape.getGeometry(i).setCapability(
 							GeometryArray.ALLOW_COORDINATE_READ);
-				}
+				}*/
 
 			}
 		}
@@ -122,5 +122,21 @@ public class PhysicalObject extends CollidableObject {
 	 */
 	public void updateTranformGroup() {
 		super.updateTransformGroup();
+	}
+
+	public Vector3f getVelocity() {
+		return this.velocity;
+	}
+	
+	public Vector3f getCenterOfMass() {
+		return this.centerOfMass;
+	}
+
+	public boolean isCollidable() {
+		return collidable;
+	}
+	
+	public boolean isNodeNull() {
+		return this.node == null;
 	}

 }
\ No newline at end of file