btStaticPlaneShape.cpp

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00001 /*
00002 Bullet Continuous Collision Detection and Physics Library
00003 Copyright (c) 2003-2009 Erwin Coumans  http://bulletphysics.org
00004 
00005 This software is provided 'as-is', without any express or implied warranty.
00006 In no event will the authors be held liable for any damages arising from the use of this software.
00007 Permission is granted to anyone to use this software for any purpose, 
00008 including commercial applications, and to alter it and redistribute it freely, 
00009 subject to the following restrictions:
00010 
00011 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.
00012 2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
00013 3. This notice may not be removed or altered from any source distribution.
00014 */
00015 
00016 #include "btStaticPlaneShape.h"
00017 
00018 #include "LinearMath/btTransformUtil.h"
00019 
00020 
00021 btStaticPlaneShape::btStaticPlaneShape(const btVector3& planeNormal,btScalar planeConstant)
00022 : btConcaveShape (), m_planeNormal(planeNormal.normalized()),
00023 m_planeConstant(planeConstant),
00024 m_localScaling(btScalar(0.),btScalar(0.),btScalar(0.))
00025 {
00026         m_shapeType = STATIC_PLANE_PROXYTYPE;
00027         //      btAssert( btFuzzyZero(m_planeNormal.length() - btScalar(1.)) );
00028 }
00029 
00030 
00031 btStaticPlaneShape::~btStaticPlaneShape()
00032 {
00033 }
00034 
00035 
00036 
00037 void btStaticPlaneShape::getAabb(const btTransform& t,btVector3& aabbMin,btVector3& aabbMax) const
00038 {
00039         (void)t;
00040         /*
00041         btVector3 infvec (btScalar(BT_LARGE_FLOAT),btScalar(BT_LARGE_FLOAT),btScalar(BT_LARGE_FLOAT));
00042 
00043         btVector3 center = m_planeNormal*m_planeConstant;
00044         aabbMin = center + infvec*m_planeNormal;
00045         aabbMax = aabbMin;
00046         aabbMin.setMin(center - infvec*m_planeNormal);
00047         aabbMax.setMax(center - infvec*m_planeNormal); 
00048         */
00049 
00050         aabbMin.setValue(btScalar(-BT_LARGE_FLOAT),btScalar(-BT_LARGE_FLOAT),btScalar(-BT_LARGE_FLOAT));
00051         aabbMax.setValue(btScalar(BT_LARGE_FLOAT),btScalar(BT_LARGE_FLOAT),btScalar(BT_LARGE_FLOAT));
00052 
00053 }
00054 
00055 
00056 
00057 
00058 void    btStaticPlaneShape::processAllTriangles(btTriangleCallback* callback,const btVector3& aabbMin,const btVector3& aabbMax) const
00059 {
00060 
00061         btVector3 halfExtents = (aabbMax - aabbMin) * btScalar(0.5);
00062         btScalar radius = halfExtents.length();
00063         btVector3 center = (aabbMax + aabbMin) * btScalar(0.5);
00064         
00065         //this is where the triangles are generated, given AABB and plane equation (normal/constant)
00066 
00067         btVector3 tangentDir0,tangentDir1;
00068 
00069         //tangentDir0/tangentDir1 can be precalculated
00070         btPlaneSpace1(m_planeNormal,tangentDir0,tangentDir1);
00071 
00072         btVector3 supVertex0,supVertex1;
00073 
00074         btVector3 projectedCenter = center - (m_planeNormal.dot(center) - m_planeConstant)*m_planeNormal;
00075         
00076         btVector3 triangle[3];
00077         triangle[0] = projectedCenter + tangentDir0*radius + tangentDir1*radius;
00078         triangle[1] = projectedCenter + tangentDir0*radius - tangentDir1*radius;
00079         triangle[2] = projectedCenter - tangentDir0*radius - tangentDir1*radius;
00080 
00081         callback->processTriangle(triangle,0,0);
00082 
00083         triangle[0] = projectedCenter - tangentDir0*radius - tangentDir1*radius;
00084         triangle[1] = projectedCenter - tangentDir0*radius + tangentDir1*radius;
00085         triangle[2] = projectedCenter + tangentDir0*radius + tangentDir1*radius;
00086 
00087         callback->processTriangle(triangle,0,1);
00088 
00089 }
00090 
00091 void    btStaticPlaneShape::calculateLocalInertia(btScalar mass,btVector3& inertia) const
00092 {
00093         (void)mass;
00094 
00095         //moving concave objects not supported
00096         
00097         inertia.setValue(btScalar(0.),btScalar(0.),btScalar(0.));
00098 }
00099 
00100 void    btStaticPlaneShape::setLocalScaling(const btVector3& scaling)
00101 {
00102         m_localScaling = scaling;
00103 }
00104 const btVector3& btStaticPlaneShape::getLocalScaling() const
00105 {
00106         return m_localScaling;
00107 }