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Bug 2806 - SOFT RENDERER: SDL_RenderCopy problems when alpha = 255
Summary: SOFT RENDERER: SDL_RenderCopy problems when alpha = 255
Status: RESOLVED FIXED
Alias: None
Product: SDL
Classification: Unclassified
Component: render (show other bugs)
Version: 2.0.3
Hardware: x86_64 Windows 7
: P2 normal
Assignee: Sam Lantinga
QA Contact: Sam Lantinga
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2014-12-06 14:44 UTC by ponce
Modified: 2016-10-07 22:18 UTC (History)
1 user (show)

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Description ponce 2014-12-06 14:44:33 UTC 
I'm drawing textures with an alpha channel with a SDL renderer.

With the hardwarer renderer (Windows) everything is fine.

With the software renderer, I see garbage in place of some textures.
Investigating, I've found than the problem was when alpha = 255.
If clamping the value to 254 on each call to SDL_SetTextureAlphaMod, then everything is fine again.

SDL_SetTextureBlendMode wasn't called (left to default).
Comment 1 Marcel Bakker 2015-11-02 11:28:36 UTC 
I have been using this fix(clamping alpha to 254) for some time now.

More people with this problem(with picture):
http://lists.libsdl.org/pipermail/sdl-libsdl.org/2015-June/098418.html

Upgrading to the latest version fixed this bug for me.
Comment 2 Sam Lantinga 2016-10-07 22:18:01 UTC 
I believe this is fixed in the latest SDL build:
http://www.libsdl.org/tmp/SDL-2.0.zip

Please reopen this bug if that's not the case.