mix: Add support for the majority of missing & new functions in newer…

… SDL_mixer versions (#612)

* mix: Added GetMusicLoopLengthTime and MusicDuration

* mix: Update and add missing documentation links

* mix: Added support for missing and new functions

Including SDL_mixer version 2.0.0, 2.0.2, 2.6.0, and 2.8.0
Added the following functions:

in sdl_mixer.go:
- LinkedVersion
- HasChunkDecoder
- HasMusicDecoder
- GetMusicAlbumTag
- GetMusicArtistTag
- GetMusicCopyrightTag
- GetMusicLoopEndTime
- GetMusicLoopStartTime
- GetMusicPosition
- GetMusicTitle
- GetMusicTitleTag
- GetMusicVolume
- MasterVolume
- ModMusicJumpToOrder
- GetNumTracks
- PauseAudio
- StartTrack

in midi.go:
- SetTimidityCfg

* mix: Fix function name typo in definition

mix/TODO.md

@@ -1,14 +1,40 @@
+## 2.8.0
+
+- [x] Mix_GetNumTracks
+- [x] Mix_PauseAudio
+- [x] Mix_StartTrack
+
+## 2.6.0
+
+- [x] Mix_GetMusicAlbumTag
+- [x] Mix_GetMusicArtistTag
+- [x] Mix_GetMusicCopyrightTag
+- [x] Mix_GetMusicLoopEndTime
+- [x] Mix_GetMusicLoopLengthTime
+- [x] Mix_GetMusicLoopStartTime
+- [x] Mix_GetMusicPosition
+- [x] Mix_GetMusicTitle
+- [x] Mix_GetMusicTitleTag
+- [x] Mix_GetMusicVolume
+- [x] Mix_HasMusicDecoder
+- [x] Mix_MasterVolume
+- [x] Mix_ModMusicJumpToOrder
+- [x] Mix_MusicDuration
+- [x] Mix_SetTimidityCfg
+
 ## 2.0.2
 
-- [ ] OpenAudioDevice()
+- [x] OpenAudioDevice()
+- [x] Mix_HasChunkDecoder
 
 ## 2.0.0
 
 - [ ] UnregisterEffect()
-- [ ] SetPostMix()
-- [ ] HookMusic()
-- [ ] HookMusicFinished()
-- [ ] ChannelFinished()
-- [ ] RegisterEffect()
-- [ ] UnregisterAllEffects()
-- [ ] EachSoundFont()
+- [x] SetPostMix()
+- [x] HookMusic()
+- [x] HookMusicFinished()
+- [x] ChannelFinished()
+- [x] RegisterEffect()
+- [x] UnregisterAllEffects()
+- [x] EachSoundFont()
+- [x] LinkedVersion()

mix/midi.go

@@ -5,6 +5,19 @@ package mix
 //#include <stdlib.h>
 //#include "sdl_mixer_wrapper.h"
 //extern int callEachSoundFont(char* str, void* udata);
+//
+//#if !(SDL_MIXER_VERSION_ATLEAST(2,6,0))
+//
+//#if defined(WARN_OUTDATED)
+//#pragma message("Mix_SetTimidityCfg is not supported before SDL 2.6.0")
+//#endif
+//
+//int Mix_SetTimidityCfg(const char *path)
+//{
+//	return 0;
+//}
+//
+//#endif
 import "C"
 import "unsafe"
 
@@ -16,19 +29,30 @@ func callEachSoundFont(str *C.char, udata unsafe.Pointer) C.int {
 }
 
 // EachSoundFont iterates over SoundFonts paths to use by supported MIDI backends.
+// (https://wiki.libsdl.org/SDL2_mixer/Mix_EachSoundFont)
 func EachSoundFont(function func(string) int) int {
 	eachSoundFontFunc = function
 	return int(C.Mix_EachSoundFont((*[0]byte)(C.callEachSoundFont), nil))
 }
 
 // SetSoundFonts sets SoundFonts paths to use by supported MIDI backends.
+// (https://wiki.libsdl.org/SDL2_mixer/Mix_SetSoundFonts)
 func SetSoundFonts(paths string) bool {
 	_paths := C.CString(paths)
 	defer C.free(unsafe.Pointer(_paths))
 	return int(C.Mix_SetSoundFonts(_paths)) == 0
 }
 
 // GetSoundFonts returns SoundFonts paths to use by supported MIDI backends.
+// (https://wiki.libsdl.org/SDL2_mixer/Mix_GetSoundFonts)
 func GetSoundFonts() string {
 	return (string)(C.GoString(C.Mix_GetSoundFonts()))
 }
+
+// Set full path of the Timidity config file. Returns true if successful, false on error. This is obviously only useful if SDL_mixer is using Timidity internally to play MIDI files.
+// (https://wiki.libsdl.org/SDL2_mixer/Mix_SetTimidityCfg)
+func SetTimidityCfg(path string) bool {
+	_path := C.CString(path)
+	defer C.free(unsafe.Pointer(_path))
+	return int(C.Mix_SetTimidityCfg(_path)) == 0
+}