# What does the alpha channel on a back buffer do?

I see that e.g. in OpenGL it is possible to create a back buffer with an alpha channel (RGBA8888). What's the effect/advantage over having an RGB888 back buffer?

• It's actually very likely that RGB888 is actually a RGBA8888 buffer. as it's cheaper to access data that's aligned to 4 byte boundaries. – ratchet freak Feb 11 '17 at 1:02

You can use the destination's alpha (backbuffer) as a factor in blending functions such as GL_DST_ALPHA and GL_ONE_MINUS_DST_ALPHA.