Play an audio chunk on a specific channel, fading in the audio.
int Mix_FadeInChannel(int channel, Mix_Chunk *chunk, int loops, int ms);
|channel||the channel on which to play the new chunk, or -1 to find any available.|
|chunk||the new chunk to play.|
|loop||the number of times the chunk should loop, -1 to loop (not actually) infinitely.|
|ms||the number of milliseconds to spend fading in.|
Returns which channel was used to play the sound, or -1 if sound could not be played.
This will start the new sound playing, much like Mix_PlayChannel() will, but will start the sound playing at silence and fade in to its normal volume over the specified number of milliseconds.
If the specified channel is -1, play on the first free channel (and return -1 without playing anything new if no free channel was available).
If a specific channel was requested, and there is a chunk already playing there, that chunk will be halted and the new chunk will take its place.
loops is greater than zero, loop the sound that many times. If
loops is -1, loop "infinitely" (~65000 times).
A fading channel will change it's volume progressively, as if Mix_Volume() was called on it (which is to say: you probably shouldn't call Mix_Volume() on a fading channel).
Note that before SDL_mixer 2.6.0, this function was a macro that called Mix_FadeInChannelTimed() with a fourth parameter ("ticks") of -1. This function still does the same thing, but promotes it to a proper API function. Older binaries linked against a newer SDL_mixer will still call Mix_FadeInChannelTimed directly, as they are using the macro, which was available since the dawn of time.
This function is available since SDL_mixer 2.6.0 (and as a macro since 2.0.0).