= ESDL2

SDL2 Erlang NIF.

The following sections list the state of the implementation
as of SDL 2.0.7. The implementation is cut into sections
corresponding to the public headers.

== Fully implemented

* 'SDL.h'
* 'SDL_blendmode.h'
* 'SDL_cpuinfo.h'
* 'SDL_filesystem.h'
* 'SDL_keyboard.h'
* 'SDL_keycode.h'
* 'SDL_mouse.h'
* 'SDL_platform.h'
* 'SDL_power.h'
* 'SDL_scancode.h'

== Partially implemented

* 'SDL_clipboard.h': We currently do not support UTF-8. We should probably switch to binaries as input/output to support it.
* 'SDL_events.h': The following events and functions are missing:
** `SDL_SYSWMEVENT`
** `SDL_TEXTEDITING`
** `SDL_TEXTINPUT`
** `SDL_JOYAXISMOTION`
** `SDL_JOYBALLMOTION`
** `SDL_JOYHATMOTION`
** `SDL_JOYBUTTONDOWN`
** `SDL_JOYBUTTONUP`
** `SDL_JOYDEVICEADDED`
** `SDL_JOYDEVICEREMOVED`
** `SDL_CONTROLLERAXISMOTION`
** `SDL_CONTROLLERBUTTONDOWN`
** `SDL_CONTROLLERBUTTONUP`
** `SDL_CONTROLLERDEVICEADDED`
** `SDL_CONTROLLERDEVICEREMOVED`
** `SDL_CONTROLLERDEVICEREMAPPED`
** `SDL_FINGERDOWN`
** `SDL_FINGERUP`
** `SDL_FINGERMOTION`
** `SDL_DOLLARGESTURE`
** `SDL_DOLLARRECORD`
** `SDL_MULTIGESTURE`
** `SDL_DROPFILE`
** `SDL_DROPTEXT`
** `SDL_DROPBEGIN`
** `SDL_DROPCOMPLETE`
** `SDL_AUDIODEVICEADDED`
** `SDL_AUDIODEVICEREMOVED`
** `SDL_PeepEvents` with action argument `SDL_ADDEVENT`
** `SDL_PushEvents`
** `SDL_SetEventFilter`
** `SDL_GetEventFilter`
** `SDL_AddEventWatch`
** `SDL_DelEventWatch`
** `SDL_FilterEvents`
** `SDL_EventState` and `SDL_GetEventState`
** `SDL_RegisterEvents`
* 'SDL_hints.h': We only have a proof of concept callback system.
* 'SDL_pixels.h': Only the pixel format enum and conversion function is defined.
* 'SDL_rect.h': Everything is missing except the map to point/rect conversion functions.
* 'SDL_render.h': The following elements are missing:
** `SDL_TextureAccess` enum
** `SDL_TextureModulate` enum
** `SDL_CreateWindowAndRenderer` is currently located in `sdl_window`. Move it?
** `SDL_CreateSoftwareRenderer` (renderer)
** `SDL_CreateTexture` (texture)
** `SDL_QueryTexture` (texture)
** `SDL_UpdateTexture` (texture)
** `SDL_UpdateYUVTexture` (texture)
** `SDL_LockTexture` (texture)
** `SDL_UnlockTexture` (texture)
** `SDL_SetRenderTarget` (renderer)
** `SDL_GetRenderTarget` (renderer)
** `SDL_RenderIsClipEnabled` (renderer)
** `SDL_RenderReadPixels` (renderer)
** `SDL_GL_BindTexture` (gl)
** `SDL_GL_UnbindTexture` (gl)
* 'SDL_stdinc.h': SDL_bool is implemented in 'sdl_bool.c'. Do we need anything else?
* 'SDL_surface.h': Only surface creation (via `IMG_Load`) and destruction is implemented. Might be better to move IMG_* functions in their own space.
* 'SDL_version.h': `SDL_GetRevisionNumber` must be implemented. The macros may also be useful.
* 'SDL_video.h': The following elements are missing:
** `SDL_WindowFlags` values SDL_WINDOW_ALWAYS_ON_TOP, SDL_WINDOW_SKIP_TASKBAR, SDL_WINDOW_UTILITY, SDL_WINDOW_TOOLTIP, SDL_WINDOW_POPUP_MENU, SDL_WINDOW_VULKAN
** `SDL_WINDOWPOS_*` values for different displays
** `SDL_GetNumDisplayModes` (video)
** `SDL_GetDisplayMode` (video)
** `SDL_GetDesktopDisplayMode` (video)
** `SDL_GetCurrentDisplayMode` (video)
** `SDL_GetClosestDisplayMode` (video)
** `SDL_GetWindowDisplayIndex` (window)
** `SDL_SetWindowDisplayMode` (window)
** `SDL_GetWindowDisplayMode` (window)
** `SDL_GetWindowPixelFormat` (window)
** `SDL_CreateWindowFrom` (window)
** `SDL_GetWindowFromID` (window)
** We currently do not support UTF-8. We should probably switch to binaries as input/output to support it for `SDL_SetWindowTitle` and `SDL_GetWindowTitle`
** `SDL_SetWindowData` (window)
** `SDL_GetWindowData` (window)
** `SDL_GetWindowBordersSize` (window)
** `SDL_SetWindowResizable` (window)
** `SDL_GetWindowSurface` (window)
** `SDL_UpdateWindowSurface` (window)
** `SDL_UpdateWindowSurfaceRects` (window)
** `SDL_GetGrabbedWindow` (window)
** `SDL_SetWindowOpacity` (window)
** `SDL_GetWindowOpacity` (window)
** `SDL_SetWindowModalFor` (window)
** `SDL_SetWindowInputFocus` (window)
** `SDL_SetWindowGammaRamp` (window)
** `SDL_GetWindowGammaRamp` (window)
** `SDL_SetWindowHitTest` and the related callback `SDL_HitTestResult`
** `SDL_IsScreenSaverEnabled`
** `SDL_EnableScreenSaver`
** `SDL_DisableScreenSaver`
** `SDL_GL_LoadLibrary` (unclear if we need it)
** `SDL_GL_GetProcAddress` (unclear if we need it)
** `SDL_GL_UnloadLibrary` (unclear if we need it)
** `SDL_GL_ExtensionSupported`
** `SDL_GL_ResetAttributes`
** `SDL_GL_SetAttribute`
** `SDL_GL_GetAttribute`
** `SDL_GL_MakeCurrent`
** `SDL_GL_GetCurrentWindow`
** `SDL_GL_GetCurrentContext`
** `SDL_GL_GetDrawableSize`
** `SDL_GL_SetSwapInterval`
** `SDL_GL_GetSwapInterval`

== To be implemented

* 'SDL_audio.h'
* 'SDL_error.h' (for completion)
* 'SDL_gamecontroller.h'
* 'SDL_gesture.h'
* 'SDL_haptic.h'
* 'SDL_joystick.h'
* 'SDL_messagebox.h'
* 'SDL_rwops.h' (unclear if we need it)
* 'SDL_shape.h'
* 'SDL_system.h'
* 'SDL_syswm.h'
* 'SDL_timer.h' (unclear if we need it)
* 'SDL_touch.h'
* 'SDL_vulkan.h'

For OpenGL we need to figure out whether we can call the functions from
wxErlang. If we can, great! If not, find an automated way to provide
access to OpenGL.

SDL extensions also need to be investigated and implemented.
We definitely want at least some of SDL_image, SDL_mixer
and SDL_ttf. We probably do not need SDL_net or SDL_rtf.

== To be removed

* `SDL_SetMainReady` which has no public interface, only the NIF function.

== Don't implement

These don't make a lot of sense for Erlang.

* 'SDL_assert.h'
* 'SDL_atomic.h'
* 'SDL_bits.h'
* 'SDL_endian.h'
* 'SDL_events.h': the functions `SDL_WaitEvent` and `SDL_WaitEventTimeout` are blocking.
* 'SDL_loadso.h'
* 'SDL_log.h'
* 'SDL_main.h'
* 'SDL_mutex.h'
* 'SDL_quit.h' (only necessary when using `SDL_Main`?)
* 'SDL_thread.h'

== Nothing to implement

These are either private headers, duplicated OpenGL/Vulkan
headers or simply deprecated.

* 'SDL_config.h'
* 'SDL_config_android.h'
* 'SDL_config_iphoneos.h'
* 'SDL_config_macosx.h'
* 'SDL_config_minimal.h'
* 'SDL_config_pandora.h'
* 'SDL_config_psp.h'
* 'SDL_config_windows.h'
* 'SDL_config_winrt.h'
* 'SDL_config_wiz.h'
* 'SDL_copying.h'
* 'SDL_egl.h'
* 'SDL_name.h'
* 'SDL_opengl.h'
* 'SDL_opengl_glext.h'
* 'SDL_opengles.h'
* 'SDL_opengles2.h'
* 'SDL_opengles2_gl2.h'
* 'SDL_opengles2_gl2ext.h'
* 'SDL_opengles2_gl2platform.h'
* 'SDL_opengles2_khrplatform.h'
* 'SDL_revision.h'
* 'SDL_test.h'
* 'SDL_test_assert.h'
* 'SDL_test_common.h'
* 'SDL_test_compare.h'
* 'SDL_test_crc32.h'
* 'SDL_test_font.h'
* 'SDL_test_fuzzer.h'
* 'SDL_test_harness.h'
* 'SDL_test_images.h'
* 'SDL_test_log.h'
* 'SDL_test_md5.h'
* 'SDL_test_memory.h'
* 'SDL_test_random.h'
* 'SDL_types.h'
* 'begin_code.h'
* 'close_code.h'