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Bug 1586 - SDL_LockTexture has inconsistent behaviour with different render drivers
Summary: SDL_LockTexture has inconsistent behaviour with different render drivers
Status: RESOLVED WONTFIX
Alias: None
Product: SDL
Classification: Unclassified
Component: video (show other bugs)
Version: HG 2.0
Hardware: All All
: P2 major
Assignee: Sam Lantinga
QA Contact: Sam Lantinga
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2012-08-27 04:38 UTC by Pallav Nawani
Modified: 2012-09-28 03:30 UTC (History)
0 users

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Description Pallav Nawani 2012-08-27 04:38:05 UTC 
Under OpenGL, SDL_LockTexture () provides access to potentially random data from system RAM. Under Direct3D, SDL_LockTexture() does actually provide access to Texture Data.

In particular this sequence will completely clobber the texture data under OpenGL:

SDL_LockTexture();
SDL_UnlockTexture();

While it will work fine under Direct3D.

This bug just caused me 3 wasted days >/
Comment 1 Sam Lantinga 2012-09-28 03:30:40 UTC 
This is an intentional optimization to make streaming textures as fast as possible.
The documentation on the wiki has been clarified:
http://wiki.libsdl.org/moin.cgi/SDL_LockTexture

Thanks!