How to make a sprite blink X seconds? - libgdx

Question

I'm using libGDX and I want to make my main character of my game to blinking x seconds on enemy touch (lose life)
Can someone tell me how can I make sprite to blinding?

Answer 1

Here is my solution, I use it exactly for the same purpose you described (blinking character when he injured).
public class Blinker {
private float BLINK_TIME = 1f;
private int BLINKING_FRAMES = 4;
private boolean isBlinking;
private int blinkFrameCounter;
private float blinkTimer;
public Blinker() {
this.blinkTimer = 0;
this.blinkFrameCounter = 0;
this.isBlinking = false;
}
public boolean shouldBlink(float delta) {
if (isBlinking) {
blinkTimer += delta;
blinkFrameCounter++;
if (blinkTimer < BLINK_TIME) {
if (blinkFrameCounter % BLINKING_FRAMES == 0) {
return true;
}
} else {
blinkTimer = 0;
isBlinking = false;
}
}
return false;
}
public boolean isBlinking() {
return isBlinking;
}
public void setBlinking(boolean isBlinking) {
this.isBlinking = isBlinking;
}
}
Usage:
first init the blinker object;
Blinker blinker= new Blinker();
blinker.setBlinking(true);
and then just add this to your draw() method (I suppose that you have separate method for drawing character, which you call in your screen draw method), before you draw the sprite you want to blink.
if (blinker.shouldBlink(delta))
return;

Answer 2

I recommend looking at something like this.
https://github.com/libgdx/libgdx/wiki/2D-Animation
You use this technique and adjust the frame duration.
walkAnimation = new Animation(0.025f, walkFrames); // #11
When you need to start making the animation blink faster. adjust the frame duration value.
public void setFrameDuration(float frameDuration)
I recommend doing it this way but if you HAVE to tint it w/e.... I guess this works.
private Texture texture;
private TextureRegion region;
private Sprite sprite;
...
texture = new Texture(Gdx.files.internal("image.png"));
region = new TextureRegion(texture, 20, 20, 50, 50);
sprite = new Sprite(texture, 20, 20, 50, 50);
sprite.setPosition(100, 10);
sprite.setColor(0, 0, 1, 1);
...
batch.begin();
batch.setColor(1, 0, 0, 1);
batch.draw(texture, 10, 10);
batch.setColor(0, 1, 0, 1);
batch.draw(region, 50, 10);
sprite.draw(batch);
batch.end();
key thing is Alpha is ignored if blending is disabled.

Answer 3

The previous answer from prgenhard will work, but I don't think that is sufficient enough, if you are using it without care.
You can use TweenEngine to interpolate alpha value with different functions.
It can be really cool.
Those values you can set on sprite's or actor's alpha and easily achieve flashing effect.
You can read more about it here:
http://www.aurelienribon.com/blog/projects/universal-tween-engine/
It should be enough.
And also it can be easily used within Libgdx engine.
Hope this helps.