The falloff is the minimum distance at which inverse distance
attenuation takes place.
A non-positive value disables distance attenuation.
In the Lua API, nil can be used to disable attenuation, a boolean can be
used to enable attenuation with a default minimum distance, or a number
can be used for full control over the parameter.
Add support for importing ambisonic WAV files and 24/32 bit PCM WAV files.
The standard ambisonic format used internally in LÖVR is ACN channel ordering with SN3D normalization.
Anything else will be converted to this form.
There are a few restrictions and assumptions:
- Only 1st order ambisonics are supported. They need to have 4 channels.
- They can be in AMB format (Furse-Malham order/normalization), detected via WAVE_EXTENSIBLE GUID.
- Any other 4 channel file is assumed to be in "AmbiX" ACN/SN3D format.
- It seems that most ambisonic files in the wild that claim to be AmbiX are just 4 channel WAVs without any metadata.
- This means that non-ambisonic 4 channel WAVs could ambiguously be mistaken as ambisonic. This is incurred as a limitation of LÖVR.
- Ambisonic files can not currently be played back. SteamAudio currently has numerous bugs with this.
- Perhaps it would be possible to write an ambisonic rotator/panning decoder to use as a default implementation.
- Compute feature requires compute shaders, image load/store, and SSBOs.
- GLSL 330 is always used, instead of changing depending on compute shader extension.
- Explicitly enable compute shaders, image load/store, and SSBO extensions when needed.
This allows implementations that don't support GLSL 430 to run compute shaders,
and keeps the min supported GL version more consistently at GL3.3.
If 64 sources are playing and a new one is started, Source:play will
return false.
Instead of a linked list, a static list of 64 Sources is used.
Bit scanning intrinsics are used to efficiently iterate the list,
using a mask (still deciding on this).