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Bug 3648 - SDL_UpdateTexture from a surface has different content than the creation from the same surface
Summary: SDL_UpdateTexture from a surface has different content than the creation fro...
Status: RESOLVED FIXED
Alias: None
Product: SDL
Classification: Unclassified
Component: render (show other bugs)
Version: 2.0.5
Hardware: x86_64 Windows 8
: P2 normal
Assignee: Sam Lantinga
QA Contact: Sam Lantinga
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2017-05-12 15:55 UTC by axel mattauch
Modified: 2017-06-29 12:40 UTC (History)
0 users

See Also:

Attachments
Very small test program (#100 lines) (5.13 KB, text/x-csrc)
2017-05-12 15:55 UTC, axel mattauch 		Details
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Description axel mattauch 2017-05-12 15:55:58 UTC 
Created attachment 2732 [details]
Very small test program (#100 lines)

Hello!

I have created a surface through 
  psurface =  SDL_CreateRGBSurfaceWithFormat
and filled the psurface surface with some color (SDL_FillRect)
Then I created a texture from this surface
  ptexture = SDL_CreateTextureFromSurface(prenderer, psurface)
The rendering (SDL_RenderCopy + SDL_RenderPresent) is OK: the screen displays effectively a surface of the color as defined by the SDL_FillRect.

But in a second step, following immediately, I updated the same texture from the same surface by:
  SDL_UpdateTexture(ptexture, NULL, psurface->pixels, psurface->pitch)
While no execution errors are occuring, the display after rendering (SDL_RenderCopy + SDL_RenderPresent)  has a wrong color.

As I simplified atmost the test sequence, I believe that the problem comes from the SDL_UpdateTexture call. 

Thanks for the help.

Axel Mattauch
Comment 1 axel mattauch 2017-06-23 14:20:30 UTC 
This bug is in close relation with #3680.
This 3648 shows only that a texture created by SDL_CreateTextureFromSurface from a give surface is modified by  SDL_UpdateTexture, even if the given surface is not changed.
#3680 shows precisely the problem (and the RGBA --> ARGB tournaround)
Comment 2 axel mattauch 2017-06-29 12:40:22 UTC 
(In reply to axel mattauch from comment #1)
> This bug is in close relation with #3680.
> This 3648 shows only that a texture created by SDL_CreateTextureFromSurface
> from a give surface is modified by  SDL_UpdateTexture, even if the given
> surface is not changed.
> #3680 shows precisely the problem (and the RGBA --> ARGB tournaround)

Thus, this topic is closed. (see #3680)