With ParticleSystem::PositionType::FREE mode, The emitted particle still follow the emitter position when set a rotation for particle.

[minggo]

Note

This issue is migrated from here. It was created at 2014/03/27 06:13:58 +0000

Description

Use this code in DemoFlower::onEnter():
`
ParticleDemo::onEnter();

_emitter = ParticleFlower::create();
_emitter->setEmissionRate(50);
_emitter->setRotation(-30);
_emitter->setAngleVar(0);
_emitter->setAngle(90);
_emitter->setRadialAccel(0);
_emitter->setTangentialAccel(0);
_emitter->retain();
_background->addChild(_emitter, 10);
_emitter->setTexture( Director::getInstance()->getTextureCache()->addImage(s_stars1) );

_background->stopAllActions();

setEmitterPosition();`

Move the particle by mouse/finger, the emitted particle will follow the emitter.

• boyu0 added comment:
  Since we have ParticleSystem::setAngleVar(); and ParticleSystem::setAngleVar(); method, the demand of rotate a ParticleSystem is not that common.
  Fix this bug has lots of "transform" work to do, without an inclusive test, add this fix to 3.0 is not safety, and it also has some performance lost.
  So I changed this issue to "Candidate for next 3.0 release".
  And here is the PR link for someone who urgent need this fix:
  closed #4577: With ParticleSystem::PositionType::FREE mode, The emitted ... #6127

[nocrim]

Is there any solution to fix this bug now?
I've done lots of search and i found out that cocos2d-iphone has a same bug from 2010. link: https://code.google.com/p/cocos2d-iphone/issues/detail?id=704
And i still have no idea how to fix it.

[nocrim]

Finally i find a way to get my expected effect now.
I was so closed without a step to change the transform mat in method "ParticleSystemQuad::draw".

if(_particleIdx > 0)
{
    //vcrim modify
    if (_positionType == PositionType::FREE) {
        _quadCommand.init(_globalZOrder, _texture->getName(), getGLProgramState(), _blendFunc, _quads, _particleIdx, Mat4());
    }
    else {
        _quadCommand.init(_globalZOrder, _texture->getName(), getGLProgramState(), _blendFunc, _quads, _particleIdx, transform);
    }
    renderer->addCommand(&_quadCommand);
}

[ricardperez]

This is pretty annoying. My setup is a particle emitter attached to a sprite, and the moment the sprite rotates the already spawned particles are rotating with it as well! 😡
Please prioritise this.

EDIT: I could temporary solve this by subclassing the particle system and overriding the method setRotation:

void ParticleSystem::setRotation(float rotation)
{
    setAngle(180.0f + rotation);
}