Hey Guys…
i was trying to achieve that particle-quads face a certain direction.
I my case i wanted to emit particles, staying in the emitters position and the particle-quads should face +y.
The usecase is to simulate expanding concentric cirles on a water surface of a fountain, as seen in the sceens.
By emp_taskforce at 2008-09-24
By emp_taskforce at 2008-09-24
I wasn’t able to achieve this with the available methods.
The screen where it looks ok, is taken from above and setCameraFacing(true)
My TestCase - feel free trying to achiev the right effect.
package com.pass.vb3d.quickwin.test;
import jmetest.effects.TestBatchParticles;
import com.jme.app.SimpleGame;
import com.jme.bounding.BoundingBox;
import com.jme.image.Texture;
import com.jme.math.FastMath;
import com.jme.math.Quaternion;
import com.jme.math.Vector3f;
import com.jme.renderer.ColorRGBA;
import com.jme.renderer.Renderer;
import com.jme.scene.Node;
import com.jme.scene.shape.Box;
import com.jme.scene.shape.Sphere;
import com.jme.scene.state.AlphaState;
import com.jme.scene.state.TextureState;
import com.jme.util.TextureManager;
import com.jmex.effects.particles.ParticleController;
import com.jmex.effects.particles.ParticleFactory;
import com.jmex.effects.particles.ParticleGeometry;
import com.jmex.effects.particles.ParticleInfluence;
import com.jmex.effects.particles.ParticleMesh;
import com.jmex.effects.particles.SimpleParticleInfluenceFactory;
public class TestParticles extends SimpleGame {
@Override
protected void simpleInitGame() {
//Set up floor and indicators for the axis.
Box floor = new Box("",Vector3f.ZERO,30,0.2f,30);
floor.setLocalTranslation(0, -0.4f, 0);
rootNode.attachChild(floor);
Box xBox = new Box("",new Vector3f(5,0,0),1,1,1);
rootNode.attachChild(xBox);
Sphere zSphere = new Sphere("", new Vector3f(0,0,5),4,4,1);
rootNode.attachChild(zSphere);
//init the particles
ParticleMesh particles = ParticleFactory.buildParticles("Fountain", 4, ParticleMesh.PT_QUAD);
particles.setLocalTranslation(0,0,0);
particles.setStartColor(ColorRGBA.blue);
particles.setEndColor(new ColorRGBA(255,0,0,0));
particles.setStartSize(1.5f);
particles.setEndSize(3);
particles.setMinimumLifeTime(500);
particles.setMaximumLifeTime(800);
particles.setEmitType(ParticleMesh.ET_POINT);
particles.setMinimumAngle(0);
particles.setMaximumAngle(0);
particles.setInitialVelocity(0.01f);
particles.setSpeed(0.3f);
particles.warmUp(1);
//dont want the particles direction to be influenced by velocity or camera
particles.setCameraFacing(false);
particles.setVelocityAligned(false);
//**Interesting Part**
//****Approach I:****
//try to rotate the particles to be emmited in +y direction and facing +y by
particles.setEmissionDirection(new Vector3f(0,0,0));
particles.setLocalRotation(new Quaternion().fromAngleAxis(FastMath.PI/2, Vector3f.UNIT_X));
// particles.setRotateWithScene(true);
// particles.setWorldEmit(new Vector3f(0,0,1));
// particles.setParticleOrientation(FastMath.PI/2);
// particles.rotateUpTo(Vector3f.UNIT_Y);
// particles.lookAt(new Vector3f(0,500,0), Vector3f.UNIT_Y);
// ParticleController controller = (ParticleController) particles.getControllers().get(0);
// controller.getParticles().setLocalRotation(new Quaternion().fromAngleAxis(FastMath.PI/2, Vector3f.UNIT_X));
// controller.getParticles().lookAt(new Vector3f(0,500,0), Vector3f.UNIT_Y);
rootNode.attachChild(particles);
//****Approach II:****
//try to put the particles into a new node and rotate the particles using the nodes translation
// particles.setLocalRotation(new Quaternion().fromAngleAxis(0, Vector3f.UNIT_X));
// Node particleNode = new Node();
// particleNode.attachChild(particles);
// particleNode.setLocalRotation(new Quaternion().fromAngleAxis(FastMath.PI/2, Vector3f.UNIT_X));
// rootNode.attachChild(particleNode);
rootNode.updateGeometricState(0, true);
rootNode.updateRenderState();
}
//main()
public static void main(String[] args) {
TestParticles app = new TestParticles();
app.start();
}
}
And although i know that jme1 is no longer updated, i searched for a bug.
I found that in its updateGeometricState() [see com.jmex.effects.particles.ParticleGeometry:996]
the worldTranslation and the worldRotation is set to zero.
commenting out these two lines enables you to freely rotate the particles facing/direction/location.
The test as it is, is working correct then, but i havent tested which results this will cause on other things.
Although it seems strange to me, that the worldTranslation and worldRotation is reset within each updatecycle.
