/**
* update position (using current position and velocity), color (interpolating between start and
* end color), size (interpolating between start and end size), spin (using parent's spin speed)
* and current age of particle. If this particle's age is greater than its lifespan, it is set to
* status DEAD.
*
* <p>Note that this only changes the parameters of the Particle, not the geometry the particle is
* associated with.
*
* @param secondsPassed number of seconds passed since last update.
* @return true if this particle is not ALIVE (in other words, if it is ready to be reused.)
*/
public boolean updateAndCheck(final double secondsPassed) {
if (status != Status.Alive) {
return true;
}
currentAge += secondsPassed * 1000; // add ms time to age
if (currentAge > lifeSpan) {
killParticle();
return true;
}
final Vector3 temp = Vector3.fetchTempInstance();
_position.addLocal(_velocity.multiply(secondsPassed * 1000f, temp));
Vector3.releaseTempInstance(temp);
// get interpolated values from appearance ramp:
parent.getRamp().getValuesAtAge(currentAge, lifeSpan, currColor, values, parent);
// interpolate colors
final int verts = ParticleSystem.getVertsForParticleType(type);
for (int x = 0; x < verts; x++) {
BufferUtils.setInBuffer(
currColor, parent.getParticleGeometry().getMeshData().getColorBuffer(), startIndex + x);
}
// check for tex animation
final int newTexIndex = parent.getTexAnimation().getTexIndexAtAge(currentAge, lifeSpan, parent);
// Update tex coords if applicable
if (currentTexIndex != newTexIndex) {
// Only supported in Quad type for now.
if (ParticleType.Quad.equals(parent.getParticleType())) {
// determine side
final float side = (float) Math.sqrt(parent.getTexQuantity());
int index = newTexIndex;
if (index >= parent.getTexQuantity()) {
index %= parent.getTexQuantity();
}
// figure row / col
final float row = side - (int) (index / side) - 1;
final float col = index % side;
// set texcoords
final float sU = col / side, eU = (col + 1) / side;
final float sV = row / side, eV = (row + 1) / side;
final FloatBuffer texs =
parent.getParticleGeometry().getMeshData().getTextureCoords(0).getBuffer();
texs.position(startIndex * 2);
texs.put(eU).put(sV);
texs.put(eU).put(eV);
texs.put(sU).put(eV);
texs.put(sU).put(sV);
texs.clear();
}
currentTexIndex = newTexIndex;
}
return false;
}
public void killParticle() {
setStatus(Status.Dead);
final Vector3 tempVec3 = Vector3.fetchTempInstance();
final FloatBuffer vertexBuffer = parent.getParticleGeometry().getMeshData().getVertexBuffer();
BufferUtils.populateFromBuffer(tempVec3, vertexBuffer, startIndex);
final int verts = ParticleSystem.getVertsForParticleType(type);
for (int x = 1; x < verts; x++) {
BufferUtils.setInBuffer(tempVec3, vertexBuffer, startIndex + x);
}
Vector3.releaseTempInstance(tempVec3);
}
/**
* Reset particle conditions. Besides the passed lifespan, we also reset color, size, and spin
* angle to their starting values (as given by parent.) Status is set to Status.Available.
*
* @param lifeSpan the recreated particle's new lifespan
*/
public void recreateParticle(final double lifeSpan) {
this.lifeSpan = lifeSpan;
final int verts = ParticleSystem.getVertsForParticleType(type);
currColor.set(parent.getStartColor());
for (int x = 0; x < verts; x++) {
BufferUtils.setInBuffer(
currColor, parent.getParticleGeometry().getMeshData().getColorBuffer(), startIndex + x);
}
values[VAL_CURRENT_SIZE] = parent.getStartSize();
currentAge = 0;
values[VAL_CURRENT_MASS] = 1;
status = Status.Available;
}
/**
* 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);
}
