/**
* Calculates the minimum bounding sphere of 4 points. Used in welzl's algorithm.
*
* @param O The 1st point inside the sphere.
* @param A The 2nd point inside the sphere.
* @param B The 3rd point inside the sphere.
* @param C The 4th point inside the sphere.
* @see #calcWelzl(java.nio.FloatBuffer)
*/
private void setSphere(final Vector3 O, final Vector3 A, final Vector3 B, final Vector3 C) {
final Vector3 a = A.subtract(O, null);
final Vector3 b = B.subtract(O, null);
final Vector3 c = C.subtract(O, null);
final double Denominator =
2.0
* (a.getX() * (b.getY() * c.getZ() - c.getY() * b.getZ())
- b.getX() * (a.getY() * c.getZ() - c.getY() * a.getZ())
+ c.getX() * (a.getY() * b.getZ() - b.getY() * a.getZ()));
if (Denominator == 0) {
_center.set(0, 0, 0);
setRadius(0);
} else {
final Vector3 o =
a.cross(b, null)
.multiplyLocal(c.lengthSquared())
.addLocal(c.cross(a, null).multiplyLocal(b.lengthSquared()))
.addLocal(b.cross(c, null).multiplyLocal(a.lengthSquared()))
.divideLocal(Denominator);
setRadius(o.length() * radiusEpsilon);
O.add(o, _center);
}
}
public void reconstruct(final Vector3 top, final Vector3 bottom, final double radius) {
// our temp vars
final Vector3 localTranslation = Vector3.fetchTempInstance();
final Vector3 capsuleUp = Vector3.fetchTempInstance();
// first make the capsule the right shape
height = top.distance(bottom);
this.radius = radius;
setGeometryData();
// now orient it in space.
localTranslation.set(_localTransform.getTranslation());
top.add(bottom, localTranslation).multiplyLocal(.5);
// rotation that takes us from 0,1,0 to the unit vector described by top/center.
top.subtract(localTranslation, capsuleUp).normalizeLocal();
final Matrix3 rotation = Matrix3.fetchTempInstance();
rotation.fromStartEndLocal(Vector3.UNIT_Y, capsuleUp);
_localTransform.setRotation(rotation);
Vector3.releaseTempInstance(localTranslation);
Vector3.releaseTempInstance(capsuleUp);
Matrix3.releaseTempInstance(rotation);
updateWorldTransform(false);
}
/**
* Calculates the minimum bounding sphere of 3 points. Used in welzl's algorithm.
*
* @param O The 1st point inside the sphere.
* @param A The 2nd point inside the sphere.
* @param B The 3rd point inside the sphere.
* @see #calcWelzl(java.nio.FloatBuffer)
*/
private void setSphere(final Vector3 O, final Vector3 A, final Vector3 B) {
final Vector3 a = A.subtract(O, null);
final Vector3 b = B.subtract(O, null);
final Vector3 acrossB = a.cross(b, null);
final double Denominator = 2.0 * acrossB.dot(acrossB);
if (Denominator == 0) {
_center.set(0, 0, 0);
setRadius(0);
} else {
final Vector3 o =
acrossB
.cross(a, null)
.multiplyLocal(b.lengthSquared())
.addLocal(b.cross(acrossB, null).multiplyLocal(a.lengthSquared()))
.divideLocal(Denominator);
setRadius(o.length() * radiusEpsilon);
O.add(o, _center);
}
}
/**
* Update the vertices for this particle, taking size, spin and viewer into consideration. In the
* case of particle type ParticleType.GeomMesh, the original triangle normal is maintained rather
* than rotating it to face the camera or parent vectors.
*
* @param cam Camera to use in determining viewer aspect. If null, or if parent is not set to
* camera facing, parent's left and up vectors are used.
*/
public void updateVerts(final Camera cam) {
final double orient = parent.getParticleOrientation() + values[VAL_CURRENT_SPIN];
final double currSize = values[VAL_CURRENT_SIZE];
if (type == ParticleSystem.ParticleType.GeomMesh
|| type == ParticleSystem.ParticleType.Point) {; // nothing to do
} else if (cam != null && parent.isCameraFacing()) {
final ReadOnlyVector3 camUp = cam.getUp();
final ReadOnlyVector3 camLeft = cam.getLeft();
final ReadOnlyVector3 camDir = cam.getDirection();
if (parent.isVelocityAligned()) {
bbX.set(_velocity).normalizeLocal().multiplyLocal(currSize);
camDir.cross(bbX, bbY).normalizeLocal().multiplyLocal(currSize);
} else if (orient == 0) {
bbX.set(camLeft).multiplyLocal(currSize);
bbY.set(camUp).multiplyLocal(currSize);
} else {
final double cA = MathUtils.cos(orient) * currSize;
final double sA = MathUtils.sin(orient) * currSize;
bbX.set(camLeft)
.multiplyLocal(cA)
.addLocal(camUp.getX() * sA, camUp.getY() * sA, camUp.getZ() * sA);
bbY.set(camLeft)
.multiplyLocal(-sA)
.addLocal(camUp.getX() * cA, camUp.getY() * cA, camUp.getZ() * cA);
}
} else {
bbX.set(parent.getLeftVector()).multiplyLocal(0);
bbY.set(parent.getUpVector()).multiplyLocal(0);
}
final Vector3 tempVec3 = Vector3.fetchTempInstance();
final FloatBuffer vertexBuffer = parent.getParticleGeometry().getMeshData().getVertexBuffer();
switch (type) {
case Quad:
{
_position.subtract(bbX, tempVec3).subtractLocal(bbY);
BufferUtils.setInBuffer(tempVec3, vertexBuffer, startIndex + 0);
_position.subtract(bbX, tempVec3).addLocal(bbY);
BufferUtils.setInBuffer(tempVec3, vertexBuffer, startIndex + 1);
_position.add(bbX, tempVec3).addLocal(bbY);
BufferUtils.setInBuffer(tempVec3, vertexBuffer, startIndex + 2);
_position.add(bbX, tempVec3).subtractLocal(bbY);
BufferUtils.setInBuffer(tempVec3, vertexBuffer, startIndex + 3);
break;
}
case GeomMesh:
{
final Quaternion tempQuat = Quaternion.fetchTempInstance();
final ReadOnlyVector3 norm = triModel.getNormal();
if (orient != 0) {
tempQuat.fromAngleNormalAxis(orient, norm);
}
for (int x = 0; x < 3; x++) {
if (orient != 0) {
tempQuat.apply(triModel.get(x), tempVec3);
} else {
tempVec3.set(triModel.get(x));
}
tempVec3.multiplyLocal(currSize).addLocal(_position);
BufferUtils.setInBuffer(tempVec3, vertexBuffer, startIndex + x);
}
Quaternion.releaseTempInstance(tempQuat);
break;
}
case Triangle:
{
_position
.subtract(3 * bbX.getX(), 3 * bbX.getY(), 3 * bbX.getZ(), tempVec3)
.subtractLocal(bbY);
BufferUtils.setInBuffer(tempVec3, vertexBuffer, startIndex + 0);
_position.add(bbX, tempVec3).addLocal(3 * bbY.getX(), 3 * bbY.getY(), 3 * bbY.getZ());
BufferUtils.setInBuffer(tempVec3, vertexBuffer, startIndex + 1);
_position.add(bbX, tempVec3).subtractLocal(bbY);
BufferUtils.setInBuffer(tempVec3, vertexBuffer, startIndex + 2);
break;
}
case Line:
{
_position.subtract(bbX, tempVec3);
BufferUtils.setInBuffer(tempVec3, vertexBuffer, startIndex);
_position.add(bbX, tempVec3);
BufferUtils.setInBuffer(tempVec3, vertexBuffer, startIndex + 1);
break;
}
case Point:
{
BufferUtils.setInBuffer(_position, vertexBuffer, startIndex);
break;
}
}
Vector3.releaseTempInstance(tempVec3);
}