I have many RGBA textures in my project. I often copy a part of one texture into another texture using copyTexSubImage2D . I am probably able to copy just a specific channel by setting mask (colorMask).
I would like to multiply (and store) the alpha of one texture by an alpha of another texture. Is it possible to do it somehow without creating and calling shaders? I am working with WebGL 1.0 (OpenGL ES 2.0).