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Simple DirectMedia Layer for Nintendo DS
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-Requirements-
* The devkitpro SDK available at http://devkitpro.org.
  Read the information at http://devkitpro.org/wiki/Getting_Started/devkitARM
  The necessary packages are devkitARM, libnds, libfat and default arm7.
* The hardware renderer is using the libgl2d abstraction library that can be found at:
    http://rel.phatcode.net/junk.php?id=117
  Build it, and install the library and the header where SDL can find them (ie. in
  the libnds/lib and libnds/include directories).


-Building SDL-

After setting the devkitpro environment, cd into your SDL directory and type:
  make -f Makefile.ds

This will compile and install the library and headers into the
devkitpro's portlibs directory. Additionnaly it will compile several
tests that you can run either on the DS or with desmume. For instance:
  desmume test/nds-test-progs/general/general.nds

-Notes-
* The renderer code is based on the gl like engine. It's not using the sprite engine.
* The port is very basic and incomplete:
  - SDL currently has to be compiled for either framebuffer mode or render mode.
     See USE_HW_RENDERER in Makefile.ds.
  - some optional renderer functions are not implemented.

-Limitations-
* in hardware renderer mode, don't load too many textures. The internal format is
  2 bytes per pixel. And there is only 256KB reserved for the textures. For instance,
  testscale won't display sample.bmp, unless it's resized to a smaller picture.
* the screen size is 256 x 384. Anything else won't work.
* there is no 8 bits/pixel mode because SDL 1.3 doesn't support palettes.

-Joystick mapping-
The Joystick presented to SDL has 2 axes and 8 buttons

 KEY      | Code
  A       |   0
  B       |   1
  X       |   2
  Y       |   3
  L       |   4
  R       |   5
  select  |   6
  start   |   7

 Left-right is axe 0.
 Up-down is axe 1.

-Mouse mapping-
todo

-Examples-
Due to memory limitations, to be able to successfully run the testscale example, sample.bmp must be resized to 256x105.
