Sam Lantinga d23d9c88e5 Fixed bug 2421 - SDL_RenderCopyEx off by one when rotating by 90 and -90
chasesan

When using SDL_RenderCopyEx, I get a problem on some platforms where the output is offset by +/-1 on other platforms and not on others. I tried it with a center of both 0,0 (and offsetting by width/height) and NULL (for centered).

The rotation involved is 90, and/or -90 rotation. The rotation was a constant, no arithmetic was involved when inputting it into SDL_RenderCopyEx.

This occurred with 32x32, 24x24, and 16x16 texture sizes. I apologize that I don't have more precise information, as I received the information as a bug report myself. But I have tracked the problem down to here.

My program requires pixel perfect alignment on several different platforms, so this is something of a showstopper for me.

--

Sylvain

It appears the RenderCopyEx is done as expected,
this is the red rectangle which is not correctly positionned !

So, here's patch with a 0.5 float increment, like for opengles2, for DrawLines, and also Draw Points.
2014-07-07 23:26:34 -07:00

                         Simple DirectMedia Layer

                                  (SDL)

                                Version 2.0

---
http://www.libsdl.org/

Simple DirectMedia Layer is a cross-platform development library designed
to provide low level access to audio, keyboard, mouse, joystick, and graphics
hardware via OpenGL and Direct3D. It is used by video playback software,
emulators, and popular games including Valve's award winning catalog
and many Humble Bundle games.

SDL officially supports Windows, Mac OS X, Linux, iOS, and Android.
Support for other platforms may be found in the source code.

SDL is written in C, works natively with C++, and there are bindings 
available for several other languages, including C# and Python.

This library is distributed under the zlib license, which can be found
in the file "COPYING.txt".

The best way to learn how to use SDL is to check out the header files in
the "include" subdirectory and the programs in the "test" subdirectory.
The header files and test programs are well commented and always up to date.
More documentation and FAQs are available online at:
	http://wiki.libsdl.org/

If you need help with the library, or just want to discuss SDL related
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If you want to report bugs or contribute patches, please submit them to
bugzilla:
    http://bugzilla.libsdl.org/

Enjoy!
	Sam Lantinga				(slouken@libsdl.org)

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Simple Directmedia Layer
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