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Bug 5392 - 0 alpha size setting not respected on EGL (Wayland)
Summary: 0 alpha size setting not respected on EGL (Wayland)
Status: ASSIGNED
Alias: None
Product: SDL
Classification: Unclassified
Component: video (show other bugs)
Version: HG 2.1
Hardware: Other Other
: P2 normal
Assignee: Ryan C. Gordon
QA Contact: Sam Lantinga
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2020-12-11 18:07 UTC by greg
Modified: 2020-12-13 03:27 UTC (History)
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Description greg 2020-12-11 18:07:30 UTC 
In sdl_egl, EGL_ALPHA_SIZE is only set if gl_config.alpha_size is "true" (non-zero):

http://hg.libsdl.org/SDL/file/6044f03a6809/src/video/SDL_egl.c#l711

But it should always be set!

On Wayland, having alpha is the default. SDL users expect no alpha to be the default – it is even mentioned in https://wiki.libsdl.org/SDL_GL_SetAttribute that SDL_GL_ALPHA_SIZE defaults to 0. But this if condition breaks that by interpreting *that* zero as "just use platform default", so there's basically no way to create an SDL window without transparency on Wayland.