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