public void draw(Canvas canvas) {
for (int i = 0; i < mParticleCount; ++i) {
Particle p = mParticles[i];
if (null != p) {
Point newPos;
if (mPositionType == PositionType.POSITION_GROUP) {
newPos = Point.sub(mPosition, p.pos);
} else {
newPos = Point.sub(p.startPos, p.pos);
}
canvas.save();
canvas.translate(newPos.x, newPos.y);
p.draw(canvas);
canvas.restore();
}
}
}
public void update(float dt) {
if (mIsActive && mEmissionRate > 0) {
float rate = 1.0f / mEmissionRate;
// issue #1201, prevent bursts of particles, due to too high emitCounter
if (mParticleCount < mTotalParticles) {
mEmitCounter += dt;
}
while (mParticleCount < mTotalParticles && mEmitCounter > rate) {
this.addParticle();
mEmitCounter -= rate;
}
mElapsed += dt;
if (mDuration != -1 && mDuration < mElapsed) {
this.stopEmitting();
}
}
mParticleIdx = 0;
if (mIsVisible) {
boolean needInvalidate = mParticleIdx < mParticleCount;
while (mParticleIdx < mParticleCount) {
Particle p = mParticles[mParticleIdx];
// life
p.timeToLive -= dt;
if (p.timeToLive > 0) {
// Mode A: gravity, direction, tangential accel & radial accel
if (mEmitterMode == EmitterMode.MODE_GRAVITY) {
Point tmp, radial, tangential;
// radial acceleration
if (p.pos.x != 0 || p.pos.y != 0) {
radial = Point.Normalize(p.pos);
} else {
radial = new Point();
}
tangential = radial;
radial = Point.mult(radial, p.modeA.radialAccel);
// tangential acceleration
float newY = tangential.x;
tangential.x = -tangential.y;
tangential.y = newY;
tangential.multBy(p.modeA.tangentialAccel);
// (gravity + radial + tangential) * dt
// tmp = Point.add(Point.add(radial, tangential), modeA.gravity);
tmp = tangential;
tmp.addBy(radial);
tmp.addBy(modeA.gravity);
tmp.multBy(dt);
p.modeA.dir.addBy(tmp);
p.pos.addBy(Point.mult(p.modeA.dir, dt));
} else { // Mode B: radius movement
// Update the angle and radius of the particle.
p.modeB.angle += p.modeB.degreesPerSecond * dt;
p.modeB.radius += p.modeB.deltaRadius * dt;
p.pos.x = (float) (-Math.cos(p.modeB.angle) * p.modeB.radius);
p.pos.y = (float) (-Math.sin(p.modeB.angle) * p.modeB.radius);
}
// color
int r = Color.red(p.color) + (int) (p.deltaColor.r * dt);
int g = Color.green(p.color) + (int) (p.deltaColor.g * dt);
int b = Color.blue(p.color) + (int) (p.deltaColor.b * dt);
int a = Color.alpha(p.color) + (int) (p.deltaColor.a * dt);
p.color = Color.argb(a, r, g, b);
// size
p.size += (p.deltaSize * dt);
p.size = Math.max(0, p.size);
// angle
p.rotation += (p.deltaRotation * dt);
// update particle counter
++mParticleIdx;
} else { // life < 0
if (mParticleIdx != mParticleCount - 1) {
mParticles[mParticleIdx].copy(mParticles[mParticleCount - 1]);
}
--mParticleCount;
}
} // while
if (needInvalidate && null != mCallbackRef) {
UpdateCallback callback = mCallbackRef.get();
if (null != callback) {
callback.needInvalidate();
}
}
}
postStep();
}
// ! Initializes a particle
protected void initParticle(Particle particle) {
// timeToLive
// no negative life. prevent division by 0
particle.timeToLive = mLife + mLifeVar * randomMinus1To1();
particle.timeToLive = Math.max(0, particle.timeToLive);
// position
particle.pos.x = mSourcePosition.x + mPosVar.x * randomMinus1To1();
particle.pos.y = mSourcePosition.y + mPosVar.y * randomMinus1To1();
// Color
int start;
int r =
Misc.clamp(
Color.red(mStartColor) + (int) (Color.red(mStartColorVar) * randomMinus1To1()), 0, 255);
int g =
Misc.clamp(
Color.green(mStartColor) + (int) (Color.green(mStartColorVar) * randomMinus1To1()),
0,
255);
int b =
Misc.clamp(
Color.blue(mStartColor) + (int) (Color.blue(mStartColorVar) * randomMinus1To1()),
0,
255);
int a =
Misc.clamp(
Color.alpha(mStartColor) + (int) (Color.alpha(mStartColorVar) * randomMinus1To1()),
0,
255);
start = Color.argb(a, r, g, b);
int end;
r =
Misc.clamp(
Color.red(mEndColor) + (int) (Color.red(mEndColorVar) * randomMinus1To1()), 0, 255);
g =
Misc.clamp(
Color.green(mEndColor) + (int) (Color.green(mEndColorVar) * randomMinus1To1()), 0, 255);
b =
Misc.clamp(
Color.blue(mEndColor) + (int) (Color.blue(mEndColorVar) * randomMinus1To1()), 0, 255);
a =
Misc.clamp(
Color.alpha(mEndColor) + (int) (Color.alpha(mEndColorVar) * randomMinus1To1()), 0, 255);
end = Color.argb(a, r, g, b);
particle.color = start;
r = (int) ((Color.red(end) - Color.red(start)) / particle.timeToLive);
g = (int) ((Color.green(end) - Color.green(start)) / particle.timeToLive);
b = (int) ((Color.blue(end) - Color.blue(start)) / particle.timeToLive);
a = (int) ((Color.alpha(end) - Color.alpha(start)) / particle.timeToLive);
particle.deltaColor = new Colour(a, r, g, b);
// size
float startS = mStartSize + mStartSizeVar * randomMinus1To1();
startS = Math.max(0, startS); // No negative value
particle.size = startS;
if (mEndSize < 0) {
particle.deltaSize = 0;
} else {
float endS = mEndSize + mEndSizeVar * randomMinus1To1();
endS = Math.max(0, endS); // No negative values
particle.deltaSize = (endS - startS) / particle.timeToLive;
}
// rotation
float startA = mStartSpin + mStartSpinVar * randomMinus1To1();
float endA = mEndSpin + mEndSpinVar * randomMinus1To1();
particle.rotation = startA;
particle.deltaRotation = (endA - startA) / particle.timeToLive;
if (mPositionType == PositionType.POSITION_GROUP) {
particle.startPos = new Point();
} else {
particle.startPos = new Point(mPosition);
}
// direction
double radians = Math.toRadians(mAngle + mAngleVar * randomMinus1To1());
// Mode Gravity: A
if (mEmitterMode == EmitterMode.MODE_GRAVITY) {
Point v = new Point((float) Math.cos(radians), (float) Math.sin(radians));
float s = modeA.speed + modeA.speedVar * randomMinus1To1();
// direction
particle.modeA.dir = Point.mult(v, s);
// radial accel
particle.modeA.radialAccel = modeA.radialAccel + modeA.radialAccelVar * randomMinus1To1();
// tangential accel
particle.modeA.tangentialAccel =
modeA.tangentialAccel + modeA.tangentialAccelVar * randomMinus1To1();
} else { // Mode Radius: B
// Set the default diameter of the particle from the source position
float startRadius = modeB.startRadius + modeB.startRadiusVar * randomMinus1To1();
float endRadius = modeB.endRadius + modeB.endRadiusVar * randomMinus1To1();
particle.modeB.radius = startRadius;
if (modeB.endRadius < 0) {
particle.modeB.deltaRadius = 0;
} else {
particle.modeB.deltaRadius = (endRadius - startRadius) / particle.timeToLive;
}
particle.modeB.angle = a;
particle.modeB.degreesPerSecond =
(float)
Math.toRadians(modeB.rotatePerSecond + modeB.rotatePerSecondVar * randomMinus1To1());
}
}
public void setPosVar(Point var) {
mPosVar.set(var.x, var.y);
}
public void setSourcePosition(Point var) {
mSourcePosition.set(var.x, var.y);
}
public void setPosition(float x, float y) {
mPosition.set(x, y);
}