1package com.jme3.effect.influencers;
2
3import com.jme3.effect.Particle;
4import com.jme3.effect.shapes.EmitterShape;
5import com.jme3.export.InputCapsule;
6import com.jme3.export.JmeExporter;
7import com.jme3.export.JmeImporter;
8import com.jme3.export.OutputCapsule;
9import com.jme3.math.FastMath;
10import com.jme3.math.Vector3f;
11import java.io.IOException;
12
13/**
14 * This emitter influences the particles so that they move all in the same direction.
15 * The direction may vary a little if the velocity variation is non zero.
16 * This influencer is default for the particle emitter.
17 * @author Marcin Roguski (Kaelthas)
18 */
19public class DefaultParticleInfluencer implements ParticleInfluencer {
20
21    /** Temporary variable used to help with calculations. */
22    protected transient Vector3f temp = new Vector3f();
23    /** The initial velocity of the particles. */
24    protected Vector3f startVelocity = new Vector3f();
25    /** The velocity's variation of the particles. */
26    protected float velocityVariation = 0.2f;
27
28    @Override
29    public void influenceParticle(Particle particle, EmitterShape emitterShape) {
30        emitterShape.getRandomPoint(particle.position);
31        this.applyVelocityVariation(particle);
32    }
33
34    /**
35     * This method applies the variation to the particle with already set velocity.
36     * @param particle
37     *        the particle to be affected
38     */
39    protected void applyVelocityVariation(Particle particle) {
40    	particle.velocity.set(startVelocity);
41        temp.set(FastMath.nextRandomFloat(), FastMath.nextRandomFloat(), FastMath.nextRandomFloat());
42        temp.multLocal(2f);
43        temp.subtractLocal(1f, 1f, 1f);
44        temp.multLocal(startVelocity.length());
45        particle.velocity.interpolate(temp, velocityVariation);
46    }
47
48    @Override
49    public void write(JmeExporter ex) throws IOException {
50        OutputCapsule oc = ex.getCapsule(this);
51        oc.write(startVelocity, "startVelocity", Vector3f.ZERO);
52        oc.write(velocityVariation, "variation", 0.2f);
53    }
54
55    @Override
56    public void read(JmeImporter im) throws IOException {
57        InputCapsule ic = im.getCapsule(this);
58        startVelocity = (Vector3f) ic.readSavable("startVelocity", Vector3f.ZERO.clone());
59        velocityVariation = ic.readFloat("variation", 0.2f);
60    }
61
62    @Override
63    public ParticleInfluencer clone() {
64        try {
65            DefaultParticleInfluencer clone = (DefaultParticleInfluencer) super.clone();
66            clone.startVelocity = startVelocity.clone();
67            return clone;
68        } catch (CloneNotSupportedException e) {
69            throw new AssertionError();
70        }
71    }
72
73    @Override
74    public void setInitialVelocity(Vector3f initialVelocity) {
75        this.startVelocity.set(initialVelocity);
76    }
77
78    @Override
79    public Vector3f getInitialVelocity() {
80        return startVelocity;
81    }
82
83    @Override
84    public void setVelocityVariation(float variation) {
85        this.velocityVariation = variation;
86    }
87
88    @Override
89    public float getVelocityVariation() {
90        return velocityVariation;
91    }
92}
93