libgdx rotation (animation, arrays) issues and help needed
- by johnny-b
well i am a noob at java and libgdx.
i got the homing bullet working with the help of someone.
now i am smashing my head as to how i can make it rotate so it faces the ball (which is the main character) when it goes around it or when it is coming towards it.
the bullet is facing <--- and the code below is what i have done so far.
also i used sprites for the bullet and also animation method.
Also how do i make it an array/arraylist which is best so i can have multiple bullets at random or placed places.
i tried many things nothing workd :(
thank you for the help.
// below is the bullet or enemy if you want to call it.
public class Bullet extends Sprite {
public static final float BULLET_HOMING = 6000;
public static final float BULLET_SPEED = 300;
private Vector2 velocity;
private float lifetime;
public Bullet(float x, float y) {
velocity = new Vector2(0, 0);
setPosition(x, y);
}
public void update(float delta) {
float targetX = GameWorld.getBall().getX();
float targetY = GameWorld.getBall().getY();
float dx = targetX - getX();
float dy = targetY - getY();
float distToTarget = (float) Math.sqrt(dx * dx + dy * dy);
dx /= distToTarget;
dy /= distToTarget;
dx *= BULLET_HOMING;
dy *= BULLET_HOMING;
velocity.x += dx * delta;
velocity.y += dy * delta;
float vMag = (float) Math.sqrt(velocity.x * velocity.x + velocity.y * velocity.y);
velocity.x /= vMag;
velocity.y /= vMag;
velocity.x *= BULLET_SPEED;
velocity.y *= BULLET_SPEED;
Vector2 v = velocity.cpy().scl(delta);
setPosition(getX() + v.x, getY() + v.y);
setOriginCenter();
setRotation(velocity.angle());
lifetime += delta;
setRegion(AssetLoader.bulletAnimation.getKeyFrame(lifetime));
}
}
// this is where i load the images.
public class AssetLoader {
public static Animation bulletAnimation;
public static Sprite bullet1, bullet2;
public static void load() {
texture = new Texture(Gdx.files.internal("SpriteN1.png"));
texture.setFilter(TextureFilter.Nearest, TextureFilter.Nearest);
bullet1 = new Sprite(texture, 380, 350, 45, 20);
bullet1.flip(false, true);
bullet2 = new Sprite(texture, 425, 350, 45, 20);
bullet2.flip(false, true);
Sprite[] bullets = { bullet1, bullet2 };
bulletAnimation = new Animation(0.06f, aims);
bulletAnimation.setPlayMode(Animation.PlayMode.LOOP);
}
public static void dispose() {
// We must dispose of the texture when we are finished.
texture.dispose();
}
// this is for the rendering of the images etc
public class GameRenderer {
private Bullet bullet;
private Ball ball;
public GameRenderer(GameWorld world) {
myWorld = world;
cam = new OrthographicCamera();
cam.setToOrtho(true, 480, 320);
batcher = new SpriteBatch();
// Attach batcher to camera
batcher.setProjectionMatrix(cam.combined);
shapeRenderer = new ShapeRenderer();
shapeRenderer.setProjectionMatrix(cam.combined);
// Call helper methods to initialize instance variables
initGameObjects();
initAssets();
}
private void initGameObjects() {
ball = GameWorld.getBall();
bullet = myWorld.getBullet();
scroller = myWorld.getScroller();
}
private void initAssets() {
ballAnimation = AssetLoader.ballAnimation;
bulletAnimation = AssetLoader.bulletAnimation;
}
public void render(float runTime) {
Gdx.gl.glClearColor(0, 0, 0, 1);
Gdx.gl.glClear(GL30.GL_COLOR_BUFFER_BIT);
batcher.begin();
// Disable transparency
// This is good for performance when drawing images that do not require
// transparency.
batcher.disableBlending();
// The ball needs transparency, so we enable that again.
batcher.enableBlending();
batcher.draw(AssetLoader.ballAnimation.getKeyFrame(runTime), ball.getX(), ball.getY(), ball.getWidth(), ball.getHeight());
batcher.draw(AssetLoader.bulletAnimation.getKeyFrame(runTime), bullet.getX(), bullet.getY());
// End SpriteBatch
batcher.end();
}
}
// this is to load the image etc on the screen i guess
public class GameWorld {
public static Ball ball;
private Bullet bullet;
private ScrollHandler scroller;
public GameWorld() {
ball = new Ball(480, 273, 32, 32);
bullet = new Bullet(10, 10);
scroller = new ScrollHandler(0);
}
public void update(float delta) {
ball.update(delta);
bullet.update(delta);
scroller.update(delta);
}
public static Ball getBall() {
return ball;
}
public ScrollHandler getScroller() {
return scroller;
}
public Bullet getBullet() {
return bullet;
}
}
so there is the whole thing.
the images are loaded via the AssetLoader then to the GameRenderer and GameWorld via the Bullet class.
i am guessing that is how it is. sorry newbie so still learning.
thank you in advace for the help or any advice.
