package org.newdawn.slick.particles;
import org.newdawn.slick.Color;
import org.newdawn.slick.Image;
import org.newdawn.slick.opengl.TextureImpl;
import org.newdawn.slick.opengl.renderer.Renderer;
import org.newdawn.slick.opengl.renderer.SGL;
/**
* A single particle within a system
*
* @author kevin
*/
public class Particle {
/** The renderer to use for all GL operations */
protected static SGL GL = Renderer.get();
/** Indicates the particle should inherit it's use of points */
public static final int INHERIT_POINTS = 1;
/** Indicates the particle should explicitly use points */
public static final int USE_POINTS = 2;
/** Indicates the particle should explicitly not use points */
public static final int USE_QUADS = 3;
/** The x coordinate of the particle */
protected float x;
/** The y coordinate of the particle */
protected float y;
/** The x component of the direction vector of the particle */
protected float velx;
/** The y component of the direction vector of the particle */
protected float vely;
/** The current size in pixels of the particle */
protected float size = 10;
/** The colour of the particle */
protected Color color = new Color(1f, 1f, 1f, 1f);
/** The life left in the particle */
protected float life;
/** The original life of this particle */
protected float originalLife;
/** The engine this particle belongs to */
private ParticleSystem engine;
/** The emitter controllng this particle */
private ParticleEmitter emitter;
/** The image for this particle */
protected Image image;
/** The type identifier of this particle */
protected int type;
/** How this particle should be rendered */
protected int usePoints = INHERIT_POINTS;
/** True if this particle's quad should be oritented based on it's direction */
protected boolean oriented = false;
/** The currently scalar applied on the y axis */
protected float scaleY = 1.0f;
/**
* Create a new particle belonging to given engine
*
* @param engine
* The engine the new particle belongs to
*/
public Particle(ParticleSystem engine) {
this.engine = engine;
}
/**
* Get the x offset of this particle
*
* @return The x offset of this particle
*/
public float getX() {
return x;
}
/**
* Get the y offset of this particle
*
* @return The y offset of this particle
*/
public float getY() {
return y;
}
/**
* Move this particle a fixed amount
*
* @param x The amount to move the particle on the horizontal axis
* @param y The amount to move the particle on the vertical axis
*/
public void move(float x, float y) {
this.x += x;
this.y += y;
}
/**
* Get the size of this particle
*
* @return The size of this particle
*/
public float getSize() {
return size;
}
/**
* Get the color of this particle
*
* @return The color of this particle
*/
public Color getColor() {
return color;
}
/**
* Set the image used to render this particle
*
* @param image
* The image used to render this particle
*/
public void setImage(Image image) {
this.image = image;
}
/**
* Get the original life of this particle
*
* @return The original life of this particle
*/
public float getOriginalLife() {
return originalLife;
}
/**
* Get the life remaining in the particle in milliseconds
*
* @return The life remaining in the particle
*/
public float getLife() {
return life;
}
/**
* Check if this particle is currently in use (i.e. is it rendering?)
*
* @return True if the particle is currently in use
*/
public boolean inUse() {
return life > 0;
}
/**
* Render this particle
*/
public void render() {
if ((engine.usePoints() && (usePoints == INHERIT_POINTS))
|| (usePoints == USE_POINTS)) {
TextureImpl.bindNone();
GL.glEnable(SGL.GL_POINT_SMOOTH);
GL.glPointSize(size / 2);
color.bind();
GL.glBegin(SGL.GL_POINTS);
GL.glVertex2f(x, y);
GL.glEnd();
} else if (oriented || scaleY != 1.0f) {
GL.glPushMatrix();
GL.glTranslatef(x, y, 0f);
if (oriented) {
float angle = (float) (Math.atan2(y, x) * 180 / Math.PI);
GL.glRotatef(angle, 0f, 0f, 1.0f);
}
// scale
GL.glScalef(1.0f, scaleY, 1.0f);
image.draw((int) (-(size / 2)), (int) (-(size / 2)), (int) size,
(int) size, color);
GL.glPopMatrix();
} else {
color.bind();
image.drawEmbedded((int) (x - (size / 2)), (int) (y - (size / 2)),
(int) size, (int) size);
}
}
/**
* Update the state of this particle
*
* @param delta
* The time since the last update
*/
public void update(int delta) {
emitter.updateParticle(this, delta);
life -= delta;
if (life > 0) {
x += delta * velx;
y += delta * vely;
} else {
engine.release(this);
}
}
/**
* Initialise the state of the particle as it's reused
*
* @param emitter
* The emitter controlling this particle
* @param life
* The life the particle should have (in milliseconds)
*/
public void init(ParticleEmitter emitter, float life) {
x = 0;
this.emitter = emitter;
y = 0;
velx = 0;
vely = 0;
size = 10;
type = 0;
this.originalLife = this.life = life;
oriented = false;
scaleY = 1.0f;
}
/**
* Set the type of this particle
*
* @param type
* The type of this particle
*/
public void setType(int type) {
this.type = type;
}
/**
* Indicate how this particle should be renered
*
* @param usePoints
* The indicator for rendering
* @see #USE_POINTS
* @see #USE_QUADS
* @see #INHERIT_POINTS
*/
public void setUsePoint(int usePoints) {
this.usePoints = usePoints;
}
/**
* Get the type of this particle
*
* @return The type of this particle
*/
public int getType() {
return type;
}
/**
* Set the size of the particle
*
* @param size
* The size of the particle (in pixels)
*/
public void setSize(float size) {
this.size = size;
}
/**
* Adjust the size of the particle
*
* @param delta
* The amount to adjust the size by (in pixels)
*/
public void adjustSize(float delta) {
size += delta;
size = Math.max(0, size);
}
/**
* Set the life of the particle
*
* @param life
* The life of the particle in milliseconds
*/
public void setLife(float life) {
this.life = life;
}
/**
* Adjust the life othe particle
*
* @param delta
* The amount to adjust the particle by (in milliseconds)
*/
public void adjustLife(float delta) {
life += delta;
}
/**
* Kill the particle, stop it rendering and send it back to the engine for
* use.
*/
public void kill() {
life = 1;
}
/**
* Set the color of the particle
*
* @param r
* The red component of the color
* @param g
* The green component of the color
* @param b
* The blue component of the color
* @param a
* The alpha component of the color
*/
public void setColor(float r, float g, float b, float a) {
color.r = r;
color.g = g;
color.b = b;
color.a = a;
}
/**
* Set the position of this particle
*
* @param x
* The new x position of the particle
* @param y
* The new y position of the particle
*/
public void setPosition(float x, float y) {
this.x = x;
this.y = y;
}
/**
* Set the velocity of the particle
*
* @param dirx
* The x component of the new velocity
* @param diry
* The y component of the new velocity
* @param speed
* The speed in the given direction
*/
public void setVelocity(float dirx, float diry, float speed) {
this.velx = dirx * speed;
this.vely = diry * speed;
}
/**
* Set the current speed of this particle
*
* @param speed The speed of this particle
*/
public void setSpeed(float speed) {
float currentSpeed = (float) Math.sqrt((velx*velx) + (vely*vely));
velx *= speed;
vely *= speed;
velx /= currentSpeed;
vely /= currentSpeed;
}
/**
* Set the velocity of the particle
*
* @param velx The x component of the new velocity
* @param vely The y component of the new velocity
*/
public void setVelocity(float velx, float vely) {
setVelocity(velx,vely,1);
}
/**
* Adjust (add) the position of this particle
*
* @param dx
* The amount to adjust the x component by
* @param dy
* The amount to adjust the y component by
*/
public void adjustPosition(float dx, float dy) {
x += dx;
y += dy;
}
/**
* Adjust (add) the color of the particle
*
* @param r
* The amount to adjust the red component by
* @param g
* The amount to adjust the green component by
* @param b
* The amount to adjust the blue component by
* @param a
* The amount to adjust the alpha component by
*/
public void adjustColor(float r, float g, float b, float a) {
color.r += r;
color.g += g;
color.b += b;
color.a += a;
}
/**
* Adjust (add) the color of the particle
*
* @param r
* The amount to adjust the red component by
* @param g
* The amount to adjust the green component by
* @param b
* The amount to adjust the blue component by
* @param a
* The amount to adjust the alpha component by
*/
public void adjustColor(int r, int g, int b, int a) {
color.r += (r / 255.0f);
color.g += (g / 255.0f);
color.b += (b / 255.0f);
color.a += (a / 255.0f);
}
/**
* Adjust (add) the direction of this particle
*
* @param dx
* The amount to adjust the x component by
* @param dy
* The amount to adjust the y component by
*/
public void adjustVelocity(float dx, float dy) {
velx += dx;
vely += dy;
}
/**
* Get the emitter that owns this particle
*
* @return The emitter that owns this particle
*/
public ParticleEmitter getEmitter() {
return emitter;
}
/**
* @see java.lang.Object#toString()
*/
public String toString() {
return super.toString() + " : " + life;
}
/**
* Check if this particle is being oriented based on it's velocity
*
* @return True if this particle being oriented based on it's velocity
*/
public boolean isOriented() {
return oriented;
}
/**
* Indicate if this particle should be oriented based on it's velocity
*
* @param oriented True if this particle is being oriented based on it's velocity
*/
public void setOriented(boolean oriented) {
this.oriented = oriented;
}
/**
* Get the current scalar applied on the y axis
*
* @return The scalar applied on the y axis
*/
public float getScaleY() {
return scaleY;
}
/**
* Set the current scalar applied on the y axis
*
* @param scaleY The new scalar to apply on the y axis
*/
public void setScaleY(float scaleY) {
this.scaleY = scaleY;
}
}