Pixmaps or Textures for dynamicalliy colored graphics in LibGdx? - libgdx

Question

I was trying to create a dynamic array containing sprites, that created from pixmap textures. I want to give randomly different colors to this array elements also.
None is working.
Then I tried to create a single pixmap. That also shows same behavior.
I created a pixmap in show() like this:
pixmap = new Pixmap(128, 128, Format.RGBA8888);
Pixmap.setBlending(Pixmap.Blending.None);
pixmap.setColor(128, 0, 0, 1f);
pixmap.fillCircle(64, 64, 64);
texture = new Texture(pixmap);
pixmap.dispose();
in render()
sprite = new Sprite(texture);
sprite.setPosition(b.getX()-sprite.getWidth()/2, b.getY()-sprite.getHeight()/2);
sprite.draw(batch);
Whenever I give an rgb color code, it gives either some different colors or black as output. Tried hex code also.
What wrong I did here?
Previousely I used pixmaps as overlay and single texture etc. But did not go deep in to it and tried.
Here, I planned to draw filled circles with pixmap, instead of using graphics. Because my game elements are very simple filled circles and more than 10 colors I should implement.
These circle objects will be generated dynamically throughout the game.
Now I am wondering what I planned to do will be effective with pixmaps. No exapmples I found on net.
Is it possible to create dynamic array with different colored objects?
Or using graphics is the better option compared to pixmaps?
It would be very helpful if I get suggestions from experienced persons.

Answer 1

r,g,b,a values should be in range from 0f to 1f. And it's bad to create new sprites in render(), since it's called every frame.
I'll try to answer your questions with this small code sample (left comments in the code):
public class MyGdxGame extends ApplicationAdapter {
SpriteBatch spriteBatch;
Pixmap pixmap;
Texture texture;
Array<Sprite> sprites = new Array<Sprite>();
#Override
public void create() {
spriteBatch = new SpriteBatch();
// you should use only one Pixmap object and one Texture object
pixmap = new Pixmap(128, 128, Pixmap.Format.RGBA8888);
pixmap.setBlending(Pixmap.Blending.None);
pixmap.setColor(Color.WHITE);
pixmap.fillCircle(64, 64, 64);
texture = new Texture(pixmap);
pixmap.dispose();
// generate sprites with different colors
// r,g,b,a values should be in range from 0f to 1f
addCircleSprite(128f / 255f, 0f, 0f, 1f);
addCircleSprite(0.4f, 0.2f, 0.5f, 1f);
addCircleSprite(0.6f, 0f, 1f, 1f);
addCircleSprite(0.3f, 0.8f, 1f, 1f);
addCircleSprite(0.1f, 1f, 1f, 1f);
}
void addCircleSprite(float r, float g, float b, float a) {
// every sprite references on the same Texture object
Sprite sprite = new Sprite(texture);
sprite.setColor(r, g, b, a);
// I just set random positions, but you should handle them differently of course
sprite.setCenter(
MathUtils.random(Gdx.graphics.getWidth()),
MathUtils.random(Gdx.graphics.getHeight()));
sprites.add(sprite);
}
#Override
public void render() {
Gdx.gl.glClearColor(0f, 0f, 0f, 1f);
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
spriteBatch.begin();
for (Sprite sprite : sprites) {
sprite.draw(spriteBatch);
}
spriteBatch.end();
}
#Override
public void dispose() {
texture.dispose();
}
}
also read this Q/A. I guess you could load your Texture object from .png file with white circle:
texture = new Texture("whiteCircle.png");
but creating Pixmap circle with only 64 pixels in radius (and then creating a Texture from it) is ok too, shouldn't make much difference.

Answer 2

setColor() takes r, g, b, a parameters to convert it to rgba8888 format -
public void setColor (float r, float g, float b, float a) {
color = Color.rgba8888(r, g, b, a);
}
So set r, g, b and alpha component as floats in the range [0,1].
use
pixmap.setColor(128f/255, 0, 0, 1f);
instead of
pixmap.setColor(128, 0, 0, 1f);
If you want to use hex then -
Color color = new Color(0x000000a6) //(Black with 65% alpha).