CODEWITHSUNDEEP
androidopengl-es-2.0textureslibgdxalpha-transparency
finlaybob
finlaybob

Reputation: 717

Why would transparency not work in LibGdx on Android 2.3.5?

I'm running into trouble with LibGdx developing an 3D Android app. I metioned it briefly in my answer to my own question, but I have been unable to figure out why I cannot get transparency from .png images.

The textures are transparent, I've checked in my OpenGL3+ framework on windows and they show transparent in the correct parts.

My (simple placeholder) fragment shader code ends with:

vec4 finalColor = ambient + diffuse;
finalColor.a = colorMap.a;
gl_FragColor = finalColor;

I've tried finalColor.a = 0.1; which doesn't work.

I've added this to my code but to no avail: 

Gdx.gl20.glEnable(GL20.GL_DEPTH_TEST);      
Gdx.gl20.glBlendFunc(GL20.GL_ALPHA, GL20.GL_ONE_MINUS_SRC_ALPHA);
Gdx.gl20.glEnable(GL20.GL_BLEND);

I've even checked and changed:

AndroidApplicationConfiguration cfg = new AndroidApplicationConfiguration();
cfg.r = cfg.g = cfg.b = cfg.a = 8;

Which I though was the number of bits per channel.

Any help at all on this would be appreciated, I just hope I've not overlooked anything. It's not a gigantic issue, and I could more or less complete my project without transparency, but would really like to know why I cant get it to work.

Upvotes: 3

Views: 3796

Answers (1)

Tim
Tim

Reputation: 35933

GL_ALPHA is not a legal option for glBlendFunc. You either want GL_SRC_ALPHA (most likely), or GL_DST_ALPHA.

glGetError would have been helpful to you here, you should start using it!

http://www.khronos.org/opengles/documentation/opengles1_0/html/glBlendFunc.html

Upvotes: 5

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