/*
* Java port of Bullet (c) 2008 Martin Dvorak <jezek2@advel.cz>
*
* Bullet Continuous Collision Detection and Physics Library
* Copyright (c) 2003-2008 Erwin Coumans http://www.bulletphysics.com/
*
* This software is provided 'as-is', without any express or implied warranty.
* In no event will the authors be held liable for any damages arising from
* the use of this software.
*
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
*
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
package com.bulletphysics.collision.shapes;
import com.bulletphysics.BulletGlobals;
import com.bulletphysics.collision.broadphase.BroadphaseNativeType;
import com.bulletphysics.linearmath.VectorUtil;
import com.bulletphysics.util.ObjectArrayList;
import cz.advel.stack.Stack;
import javax.vecmath.Vector3f;
/**
* ConvexHullShape implements an implicit convex hull of an array of vertices.
* Bullet provides a general and fast collision detector for convex shapes based
* on GJK and EPA using localGetSupportingVertex.
*
* @author jezek2
*/
public class ConvexHullShape extends PolyhedralConvexShape {
private final ObjectArrayList<Vector3f> points = new ObjectArrayList<Vector3f>();
/**
* TODO: This constructor optionally takes in a pointer to points. Each point is assumed to be 3 consecutive float (x,y,z), the striding defines the number of bytes between each point, in memory.
* It is easier to not pass any points in the constructor, and just add one point at a time, using addPoint.
* ConvexHullShape make an internal copy of the points.
*/
// TODO: make better constuctors (ByteBuffer, etc.)
public ConvexHullShape(ObjectArrayList<Vector3f> points) {
// JAVA NOTE: rewritten
for (int i=0; i<points.size(); i++) {
this.points.add(new Vector3f(points.getQuick(i)));
}
recalcLocalAabb();
}
@Override
public void setLocalScaling(Vector3f scaling) {
localScaling.set(scaling);
recalcLocalAabb();
}
public void addPoint(Vector3f point) {
points.add(new Vector3f(point));
recalcLocalAabb();
}
public ObjectArrayList<Vector3f> getPoints() {
return points;
}
public int getNumPoints() {
return points.size();
}
@Override
public Vector3f localGetSupportingVertexWithoutMargin(Vector3f vec0, Vector3f out) {
Vector3f supVec = out;
supVec.set(0f, 0f, 0f);
float newDot, maxDot = -1e30f;
Vector3f vec = Stack.alloc(vec0);
float lenSqr = vec.lengthSquared();
if (lenSqr < 0.0001f) {
vec.set(1f, 0f, 0f);
}
else {
float rlen = 1f / (float) Math.sqrt(lenSqr);
vec.scale(rlen);
}
Vector3f vtx = Stack.alloc(Vector3f.class);
for (int i = 0; i < points.size(); i++) {
VectorUtil.mul(vtx, points.getQuick(i), localScaling);
newDot = vec.dot(vtx);
if (newDot > maxDot) {
maxDot = newDot;
supVec.set(vtx);
}
}
return out;
}
@Override
public void batchedUnitVectorGetSupportingVertexWithoutMargin(Vector3f[] vectors, Vector3f[] supportVerticesOut, int numVectors) {
float newDot;
// JAVA NOTE: rewritten as code used W coord for temporary usage in Vector3
// TODO: optimize it
float[] wcoords = new float[numVectors];
// use 'w' component of supportVerticesOut?
{
for (int i = 0; i < numVectors; i++) {
//supportVerticesOut[i][3] = btScalar(-1e30);
wcoords[i] = -1e30f;
}
}
Vector3f vtx = Stack.alloc(Vector3f.class);
for (int i = 0; i < points.size(); i++) {
VectorUtil.mul(vtx, points.getQuick(i), localScaling);
for (int j = 0; j < numVectors; j++) {
Vector3f vec = vectors[j];
newDot = vec.dot(vtx);
//if (newDot > supportVerticesOut[j][3])
if (newDot > wcoords[j]) {
// WARNING: don't swap next lines, the w component would get overwritten!
supportVerticesOut[j].set(vtx);
//supportVerticesOut[j][3] = newDot;
wcoords[j] = newDot;
}
}
}
}
@Override
public Vector3f localGetSupportingVertex(Vector3f vec, Vector3f out) {
Vector3f supVertex = localGetSupportingVertexWithoutMargin(vec, out);
if (getMargin() != 0f) {
Vector3f vecnorm = Stack.alloc(vec);
if (vecnorm.lengthSquared() < (BulletGlobals.FLT_EPSILON * BulletGlobals.FLT_EPSILON)) {
vecnorm.set(-1f, -1f, -1f);
}
vecnorm.normalize();
supVertex.scaleAdd(getMargin(), vecnorm, supVertex);
}
return out;
}
/**
* Currently just for debugging (drawing), perhaps future support for algebraic continuous collision detection.
* Please note that you can debug-draw ConvexHullShape with the Raytracer Demo.
*/
@Override
public int getNumVertices() {
return points.size();
}
@Override
public int getNumEdges() {
return points.size();
}
@Override
public void getEdge(int i, Vector3f pa, Vector3f pb) {
int index0 = i % points.size();
int index1 = (i + 1) % points.size();
VectorUtil.mul(pa, points.getQuick(index0), localScaling);
VectorUtil.mul(pb, points.getQuick(index1), localScaling);
}
@Override
public void getVertex(int i, Vector3f vtx) {
VectorUtil.mul(vtx, points.getQuick(i), localScaling);
}
@Override
public int getNumPlanes() {
return 0;
}
@Override
public void getPlane(Vector3f planeNormal, Vector3f planeSupport, int i) {
assert false;
}
@Override
public boolean isInside(Vector3f pt, float tolerance) {
assert false;
return false;
}
@Override
public BroadphaseNativeType getShapeType() {
return BroadphaseNativeType.CONVEX_HULL_SHAPE_PROXYTYPE;
}
@Override
public String getName() {
return "Convex";
}
}