game-audio-guide

Game Audio Plugin Implementation Guide

Steps apply to both Wwise and FMOD unless noted.

Step 1 — Choose middleware and plugin type

Middleware	Effect plugin	Source plugin	Mixer plugin
Wwise	IAkInPlaceEffectPlugin or IAkOutOfPlaceEffectPlugin	IAkSourcePlugin	IAkMixerEffectPlugin
FMOD	FMOD_DSP_DESCRIPTION (process callback)	FMOD_DSP_DESCRIPTION (generatetone or read)	FMOD_DSP_DESCRIPTION on a bus

• Effect plugins modify an existing signal in place or out of place.
• Source plugins generate audio from scratch (synthesisers, procedural audio).
• Mixer plugins operate on a mix bus and see the summed signal from all inputs.
• Confirm the plugin type before writing any code — changing it later requires reworking the descriptor and callback signatures.

Step 2 — Set up the plugin descriptor

Wwise:

• Declare an AkPluginInfo struct with your company ID, plugin ID, and plugin type.
• Implement GetPluginInfo() to return it from your plugin class.
• Provide a CreateXxx factory function and register it with AK::SoundEngine::RegisterPlugin.
• Implement a matching AkPluginParamBase subclass for parameter storage.

FMOD:

• Declare an FMOD_DSP_DESCRIPTION struct with name, version, channel counts, and all callback pointers.
• Fill FMOD_DSP_PARAMETER_DESC entries for every parameter the DSP exposes.
• Export a FMODGetDSPDescription() function (or pass the struct directly to FMOD::System::createDSP).
• Keep the description in static storage — FMOD holds a pointer to it for the lifetime of the DSP.

Step 3 — Implement the audio callback

Wwise (Execute):

• Read channel count and frame count from AkAudioBuffer at runtime — never hardcode.
• Use io_pBuffer->GetChannel(ch) to access per-channel float pointers.
• Allocate during Init with the AK::IAkPluginMemAlloc* allocator; never allocate inside Execute.
• Return early if uValidFrames == 0 to avoid processing silent tail unnecessarily.