Set the "distance" of a channel.
int Mix_SetDistance(int channel, Uint8 distance);
|channel||The mixer channel to attenuate, or MIX_CHANNEL_POST.|
|distance||distance; 0 is the listener, 255 is maxiumum distance away.|
Returns zero if error (no such channel or Mix_RegisterEffect() fails), nonzero if position effect is enabled. Error messages can be retrieved from Mix_GetError().
distance is an integer from 0 to 255 that specifies the location of the sound in relation to the listener. Distance 0 is overlapping the listener, and 255 is as far away as possible. A distance of 255 does not guarantee silence; in such a case, you might want to try changing the chunk's volume, or just cull the sample from the mixing process with Mix_HaltChannel(). For efficiency, the precision of this effect may be limited (distances 1 through 7 might all produce the same effect, 8 through 15 are equal, etc). (distance) is an integer between 0 and 255 that specifies the space between the sound and the listener. The larger the number, the further away the sound is. Setting the distance to 0 unregisters this effect, since the data would be unchanged. If you need more precise positional audio, consider using OpenAL for spatialized effects instead of SDL_mixer. This is only meant to be a basic effect for simple "3D" games.
Setting the channel to MIX_CHANNEL_POST registers this as a posteffect, and the distance attenuation will be done to the final mixed stream before passing it on to the audio device.
This uses the Mix_RegisterEffect() API internally.
Note that unlike most SDL and SDL_mixer functions, this function returns zero if there's an error, not on success. We apologize for the API design inconsistency here.
This function is available since SDL_mixer 2.0.0.