How to deal with etc1 alpha channel

Question

I'm trying to support ETC1 for my android game but I have no idea how to deal with the alpha channel.

Can anyone tell me where to start and how to get ETC1 working with alpha?

Update: Using: gl_fragColor = vec4(tex1.rgb,tex2.a);

doesn't work, there is still a black rectangle around my texture

Answer 1

您需要使用alphamask着色器。

基本上没有包含透明度的全色信息的1个纹理，rgb（etc1）有1个纹理，alpha有1个纹理（也可以是etc1）。

然后在片段着色器中，从第一个纹理分配rgb，从第二个纹理分配alpha。

 gl_fragColor = vec4(tex1.rgb,tex2.a);

！注意上面的代码只是用于解释方法，语法可能是错误的。