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Bug 4425

Summary: SDL_CreateTextureFromSurface forget to choose an alpha format for palettes with alpha values
Product: SDL Reporter: Sylvain <sylvain.becker>
Component: renderAssignee: Sam Lantinga <slouken>
Status: RESOLVED FIXED QA Contact: Sam Lantinga <slouken>
Severity: normal    
Priority: P2    
Version: don't know   
Hardware: All   
OS: All   
Attachments: test case

Description Sylvain 2018-12-15 13:41:16 UTC 
SDL_CreateTextureFromSurface() forget to choose a texture format with alpha for surfaces that have palette with alpha values.

In the end, it works with opengl renderer because it only has a unique format which has alpha, but it fails with software and opengles2 as it choose a non alpha format.
Comment 1 Sylvain 2018-12-15 13:42:13 UTC 
Created attachment 3547 [details]
test case
Comment 2 Sylvain 2018-12-15 13:51:31 UTC 
Fixed in https://hg.libsdl.org/SDL/rev/6e387413a916
Comment 3 Sylvain 2020-02-23 09:03:17 UTC 
https://hg.libsdl.org/SDL/rev/c66d1c7700bd

Fixed bug 4999 - Palette surface always promoted to alpha (Thanks Cameron Gutman!)
MSVC Static analysis: Incorrect alpha_value check in SDL_render.c
Comment 4 Sylvain 2020-02-23 09:06:15 UTC 
re-open because there is another issue with this situation:

- a palette surface without alpha value, but all alpha field with 0.
- using the GLES 1 render, that only has ARGB texture.

=> the texture is always transparent, whereas it should be opaque.
Comment 5 Sylvain 2020-02-23 22:06:43 UTC 
Fixed in bug 3827 which has a long history