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Code Issues Releases Wiki Activity

fix 'safeNormalize' (probably should remove it)

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Fix for Issue 953: cull degenerate triangles
https://github.com/bulletphysics/bullet3/issues/935
Thanks to Oleg Klimov for the report and reproduction case.
This commit is contained in:
erwincoumans 2017-01-30 18:12:09 -08:00
parent 26a34e3cda
commit 72dd8285e8
4 changed files with 70 additions and 54 deletions
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19
examples/ExampleBrowser/CollisionShape2TriangleMesh.cpp
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@ -111,19 +111,22 @@ void CollisionShape2TriangleMesh(btCollisionShape* collisionShape, const btTrans
vertices.push_back(triangleVerts[2]);
btVector3 triNormal = (triangleVerts[1]-triangleVerts[0]).cross(triangleVerts[2]-triangleVerts[0]);
triNormal.normalize();
btScalar dot = triNormal.dot(triNormal);
for (int v=0;v<3;v++)
//cull degenerate triangles
if (dot >= SIMD_EPSILON*SIMD_EPSILON)
{
triNormal /= btSqrt(dot);
for (int v = 0; v < 3; v++)
{
btVector3 pos =parentTransform*triangleVerts[v];
indicesOut.push_back(vertexPositions.size());
vertexPositions.push_back(pos);
vertexNormals.push_back(triNormal);
btVector3 pos = parentTransform*triangleVerts[v];
indicesOut.push_back(vertexPositions.size());
vertexPositions.push_back(pos);
vertexNormals.push_back(triNormal);
}
}
}
}

14
src/Bullet3Common/b3Vector3.h
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@ -249,14 +249,16 @@ public:
B3_FORCE_INLINE b3Vector3& safeNormalize()
{
b3Vector3 absVec = this->absolute();
int maxIndex = absVec.maxAxis();
if (absVec[maxIndex]>0)
b3Scalar l2 = length2();
//triNormal.normalize();
if (l2 >= B3_EPSILON*B3_EPSILON)
{
*this /= absVec[maxIndex];
return *this /= length();
(*this) /= b3Sqrt(l2);
}
else
{
setValue(1, 0, 0);
}
setValue(1,0,0);
return *this;
}

73
src/BulletCollision/CollisionDispatch/SphereTriangleDetector.cpp
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@ -100,45 +100,54 @@ bool SphereTriangleDetector::collide(const btVector3& sphereCenter,btVector3 &po
btScalar radiusWithThreshold = radius + contactBreakingThreshold;
btVector3 normal = (vertices[1]-vertices[0]).cross(vertices[2]-vertices[0]);
normal.safeNormalize();
btVector3 p1ToCentre = sphereCenter - vertices[0];
btScalar distanceFromPlane = p1ToCentre.dot(normal);
if (distanceFromPlane < btScalar(0.))
{
//triangle facing the other way
distanceFromPlane *= btScalar(-1.);
normal *= btScalar(-1.);
}
bool isInsideContactPlane = distanceFromPlane < radiusWithThreshold;
// Check for contact / intersection
btScalar l2 = normal.length2();
bool hasContact = false;
btVector3 contactPoint;
if (isInsideContactPlane) {
if (facecontains(sphereCenter,vertices,normal)) {
// Inside the contact wedge - touches a point on the shell plane
hasContact = true;
contactPoint = sphereCenter - normal*distanceFromPlane;
} else {
// Could be inside one of the contact capsules
btScalar contactCapsuleRadiusSqr = radiusWithThreshold*radiusWithThreshold;
btVector3 nearestOnEdge;
for (int i = 0; i < m_triangle->getNumEdges(); i++) {
btVector3 pa;
btVector3 pb;
if (l2 >= SIMD_EPSILON*SIMD_EPSILON)
{
normal /= btSqrt(l2);
m_triangle->getEdge(i,pa,pb);
btVector3 p1ToCentre = sphereCenter - vertices[0];
btScalar distanceFromPlane = p1ToCentre.dot(normal);
if (distanceFromPlane < btScalar(0.))
{
//triangle facing the other way
distanceFromPlane *= btScalar(-1.);
normal *= btScalar(-1.);
}
bool isInsideContactPlane = distanceFromPlane < radiusWithThreshold;
// Check for contact / intersection
if (isInsideContactPlane) {
if (facecontains(sphereCenter, vertices, normal)) {
// Inside the contact wedge - touches a point on the shell plane
hasContact = true;
contactPoint = sphereCenter - normal*distanceFromPlane;
}
else {
// Could be inside one of the contact capsules
btScalar contactCapsuleRadiusSqr = radiusWithThreshold*radiusWithThreshold;
btVector3 nearestOnEdge;
for (int i = 0; i < m_triangle->getNumEdges(); i++) {
btVector3 pa;
btVector3 pb;
m_triangle->getEdge(i, pa, pb);
btScalar distanceSqr = SegmentSqrDistance(pa, pb, sphereCenter, nearestOnEdge);
if (distanceSqr < contactCapsuleRadiusSqr) {
// Yep, we're inside a capsule
hasContact = true;
contactPoint = nearestOnEdge;
}
btScalar distanceSqr = SegmentSqrDistance(pa,pb,sphereCenter, nearestOnEdge);
if (distanceSqr < contactCapsuleRadiusSqr) {
// Yep, we're inside a capsule
hasContact = true;
contactPoint = nearestOnEdge;
}
}
}
}

14
src/LinearMath/btVector3.h
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@ -291,14 +291,16 @@ public:
SIMD_FORCE_INLINE btVector3& safeNormalize()
{
btVector3 absVec = this->absolute();
int maxIndex = absVec.maxAxis();
if (absVec[maxIndex]>0)
btScalar l2 = length2();
//triNormal.normalize();
if (l2 >= SIMD_EPSILON*SIMD_EPSILON)
{
*this /= absVec[maxIndex];
return *this /= length();
(*this) /= btSqrt(l2);
}
else
{
setValue(1, 0, 0);
}
setValue(1,0,0);
return *this;
}