用于背景精灵的Android Alpha透明度无法达到预期效果

Question

I am using AndEngine-GLES2 and when i am trying to fade in the background for a new scene, the image is first displayed for a fraction of second and then it fades in as i needed. But that image being displayed without alpha transparency initially for a fraction of a second is making it look glitchy.

Here is my code to load the image

I am loading the sprite like,

bgSprite = new Sprite(0, 0, bgTextureRegion, LaunchGame.getSharedInstance().getEngine().getVertexBufferObjectManager());

And I am setting alpha transparency and fade in effects as

bgSprite.setBlendFunction(GL10.GL_SRC_ALPHA, GL10.GL_ONE_MINUS_SRC_ALPHA);
    final IEntityModifier iem = new AlphaModifier(1,0.0f,1.0f);
    iem.setAutoUnregisterWhenFinished(true);
    bgSprite.registerEntityModifier(iem);
    attachChild(bgSprite);

I tried to override the preDraw function of sprite but it dint help. What could be the problem or any more data required? Or am I missing something stupid?

Answer 1

Just add:

bgSprite.setAlpha(0.0f); 

before you attach your background. By default your sprite is attached with alpha (1.0) (thats why it shows up for a sec, and then the modifier is fired so instantly it goes to alpha(0.0f) and goes to 1.0f again slowly.