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JBullet - Java port of Bullet Physics Library
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/*
* Java port of Bullet (c) 2008 Martin Dvorak
*
* 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.collision.broadphase.BroadphaseNativeType;
import com.bulletphysics.collision.dispatch.CollisionObject;
import com.bulletphysics.dynamics.RigidBody;
import com.bulletphysics.linearmath.AabbUtil2;
import com.bulletphysics.linearmath.ScalarUtil;
import com.bulletphysics.linearmath.Transform;
import com.bulletphysics.linearmath.VectorUtil;
import cz.advel.stack.Stack;
import javax.vecmath.Vector3f;
import javax.vecmath.Vector4f;
/**
* BoxShape is a box primitive around the origin, its sides axis aligned with length
* specified by half extents, in local shape coordinates. When used as part of a
* {@link CollisionObject} or {@link RigidBody} it will be an oriented box in world space.
*
* @author jezek2
*/
public class BoxShape extends PolyhedralConvexShape {
public BoxShape(Vector3f boxHalfExtents) {
Vector3f margin = new Vector3f(getMargin(), getMargin(), getMargin());
VectorUtil.mul(implicitShapeDimensions, boxHalfExtents, localScaling);
implicitShapeDimensions.sub(margin);
}
public Vector3f getHalfExtentsWithMargin(Vector3f out) {
Vector3f halfExtents = getHalfExtentsWithoutMargin(out);
Vector3f margin = Stack.alloc(Vector3f.class);
margin.set(getMargin(), getMargin(), getMargin());
halfExtents.add(margin);
return out;
}
public Vector3f getHalfExtentsWithoutMargin(Vector3f out) {
out.set(implicitShapeDimensions); // changed in Bullet 2.63: assume the scaling and margin are included
return out;
}
@Override
public BroadphaseNativeType getShapeType() {
return BroadphaseNativeType.BOX_SHAPE_PROXYTYPE;
}
@Override
public Vector3f localGetSupportingVertex(Vector3f vec, Vector3f out) {
Vector3f halfExtents = getHalfExtentsWithoutMargin(out);
float margin = getMargin();
halfExtents.x += margin;
halfExtents.y += margin;
halfExtents.z += margin;
out.set(
ScalarUtil.fsel(vec.x, halfExtents.x, -halfExtents.x),
ScalarUtil.fsel(vec.y, halfExtents.y, -halfExtents.y),
ScalarUtil.fsel(vec.z, halfExtents.z, -halfExtents.z));
return out;
}
@Override
public Vector3f localGetSupportingVertexWithoutMargin(Vector3f vec, Vector3f out) {
Vector3f halfExtents = getHalfExtentsWithoutMargin(out);
out.set(
ScalarUtil.fsel(vec.x, halfExtents.x, -halfExtents.x),
ScalarUtil.fsel(vec.y, halfExtents.y, -halfExtents.y),
ScalarUtil.fsel(vec.z, halfExtents.z, -halfExtents.z));
return out;
}
@Override
public void batchedUnitVectorGetSupportingVertexWithoutMargin(Vector3f[] vectors, Vector3f[] supportVerticesOut, int numVectors) {
Vector3f halfExtents = getHalfExtentsWithoutMargin(Stack.alloc(Vector3f.class));
for (int i = 0; i < numVectors; i++) {
Vector3f vec = vectors[i];
supportVerticesOut[i].set(ScalarUtil.fsel(vec.x, halfExtents.x, -halfExtents.x),
ScalarUtil.fsel(vec.y, halfExtents.y, -halfExtents.y),
ScalarUtil.fsel(vec.z, halfExtents.z, -halfExtents.z));
}
}
@Override
public void setMargin(float margin) {
// correct the implicitShapeDimensions for the margin
Vector3f oldMargin = Stack.alloc(Vector3f.class);
oldMargin.set(getMargin(), getMargin(), getMargin());
Vector3f implicitShapeDimensionsWithMargin = Stack.alloc(Vector3f.class);
implicitShapeDimensionsWithMargin.add(implicitShapeDimensions, oldMargin);
super.setMargin(margin);
Vector3f newMargin = Stack.alloc(Vector3f.class);
newMargin.set(getMargin(), getMargin(), getMargin());
implicitShapeDimensions.sub(implicitShapeDimensionsWithMargin, newMargin);
}
@Override
public void setLocalScaling(Vector3f scaling) {
Vector3f oldMargin = Stack.alloc(Vector3f.class);
oldMargin.set(getMargin(), getMargin(), getMargin());
Vector3f implicitShapeDimensionsWithMargin = Stack.alloc(Vector3f.class);
implicitShapeDimensionsWithMargin.add(implicitShapeDimensions, oldMargin);
Vector3f unScaledImplicitShapeDimensionsWithMargin = Stack.alloc(Vector3f.class);
VectorUtil.div(unScaledImplicitShapeDimensionsWithMargin, implicitShapeDimensionsWithMargin, localScaling);
super.setLocalScaling(scaling);
VectorUtil.mul(implicitShapeDimensions, unScaledImplicitShapeDimensionsWithMargin, localScaling);
implicitShapeDimensions.sub(oldMargin);
}
@Override
public void getAabb(Transform t, Vector3f aabbMin, Vector3f aabbMax) {
AabbUtil2.transformAabb(getHalfExtentsWithoutMargin(Stack.alloc(Vector3f.class)), getMargin(), t, aabbMin, aabbMax);
}
@Override
public void calculateLocalInertia(float mass, Vector3f inertia) {
//btScalar margin = btScalar(0.);
Vector3f halfExtents = getHalfExtentsWithMargin(Stack.alloc(Vector3f.class));
float lx = 2f * halfExtents.x;
float ly = 2f * halfExtents.y;
float lz = 2f * halfExtents.z;
inertia.set(mass / 12f * (ly * ly + lz * lz),
mass / 12f * (lx * lx + lz * lz),
mass / 12f * (lx * lx + ly * ly));
}
@Override
public void getPlane(Vector3f planeNormal, Vector3f planeSupport, int i) {
// this plane might not be aligned...
Vector4f plane = Stack.alloc(Vector4f.class);
getPlaneEquation(plane, i);
planeNormal.set(plane.x, plane.y, plane.z);
Vector3f tmp = Stack.alloc(Vector3f.class);
tmp.negate(planeNormal);
localGetSupportingVertex(tmp, planeSupport);
}
@Override
public int getNumPlanes() {
return 6;
}
@Override
public int getNumVertices() {
return 8;
}
@Override
public int getNumEdges() {
return 12;
}
@Override
public void getVertex(int i, Vector3f vtx) {
Vector3f halfExtents = getHalfExtentsWithoutMargin(Stack.alloc(Vector3f.class));
vtx.set(halfExtents.x * (1 - (i & 1)) - halfExtents.x * (i & 1),
halfExtents.y * (1 - ((i & 2) >> 1)) - halfExtents.y * ((i & 2) >> 1),
halfExtents.z * (1 - ((i & 4) >> 2)) - halfExtents.z * ((i & 4) >> 2));
}
public void getPlaneEquation(Vector4f plane, int i) {
Vector3f halfExtents = getHalfExtentsWithoutMargin(Stack.alloc(Vector3f.class));
switch (i) {
case 0:
plane.set(1f, 0f, 0f, -halfExtents.x);
break;
case 1:
plane.set(-1f, 0f, 0f, -halfExtents.x);
break;
case 2:
plane.set(0f, 1f, 0f, -halfExtents.y);
break;
case 3:
plane.set(0f, -1f, 0f, -halfExtents.y);
break;
case 4:
plane.set(0f, 0f, 1f, -halfExtents.z);
break;
case 5:
plane.set(0f, 0f, -1f, -halfExtents.z);
break;
default:
assert (false);
}
}
@Override
public void getEdge(int i, Vector3f pa, Vector3f pb) {
int edgeVert0 = 0;
int edgeVert1 = 0;
switch (i) {
case 0:
edgeVert0 = 0;
edgeVert1 = 1;
break;
case 1:
edgeVert0 = 0;
edgeVert1 = 2;
break;
case 2:
edgeVert0 = 1;
edgeVert1 = 3;
break;
case 3:
edgeVert0 = 2;
edgeVert1 = 3;
break;
case 4:
edgeVert0 = 0;
edgeVert1 = 4;
break;
case 5:
edgeVert0 = 1;
edgeVert1 = 5;
break;
case 6:
edgeVert0 = 2;
edgeVert1 = 6;
break;
case 7:
edgeVert0 = 3;
edgeVert1 = 7;
break;
case 8:
edgeVert0 = 4;
edgeVert1 = 5;
break;
case 9:
edgeVert0 = 4;
edgeVert1 = 6;
break;
case 10:
edgeVert0 = 5;
edgeVert1 = 7;
break;
case 11:
edgeVert0 = 6;
edgeVert1 = 7;
break;
default:
assert (false);
}
getVertex(edgeVert0, pa);
getVertex(edgeVert1, pb);
}
@Override
public boolean isInside(Vector3f pt, float tolerance) {
Vector3f halfExtents = getHalfExtentsWithoutMargin(Stack.alloc(Vector3f.class));
//btScalar minDist = 2*tolerance;
boolean result =
(pt.x <= (halfExtents.x + tolerance)) &&
(pt.x >= (-halfExtents.x - tolerance)) &&
(pt.y <= (halfExtents.y + tolerance)) &&
(pt.y >= (-halfExtents.y - tolerance)) &&
(pt.z <= (halfExtents.z + tolerance)) &&
(pt.z >= (-halfExtents.z - tolerance));
return result;
}
@Override
public String getName() {
return "Box";
}
@Override
public int getNumPreferredPenetrationDirections() {
return 6;
}
@Override
public void getPreferredPenetrationDirection(int index, Vector3f penetrationVector) {
switch (index) {
case 0:
penetrationVector.set(1f, 0f, 0f);
break;
case 1:
penetrationVector.set(-1f, 0f, 0f);
break;
case 2:
penetrationVector.set(0f, 1f, 0f);
break;
case 3:
penetrationVector.set(0f, -1f, 0f);
break;
case 4:
penetrationVector.set(0f, 0f, 1f);
break;
case 5:
penetrationVector.set(0f, 0f, -1f);
break;
default:
assert (false);
}
}
}