Emitter Gain Formula

This function converts raytracing energy values to low-pass filter gain values.

The GainFormula is invoked twice per source emitter

• Once with low-frequency energy values
• Once with high-frequency energy values

The results of these functions are stored directly on the emitter's filter and accessed via listener.GetTargetFilter(target)).

The default formula specifies that 15% of occlusion energy or 15% of permeation energy is required for an emitter to be at max volume:

target.GainFormula = (bool lowFrequency, int occlusionRayCount, int permeationRayCount, int permeationBounceCount, float occlusionEnergy, float permeationEnergy) =>
{
    float gain = 0.0f;

    // 15% of energy is considered enough for the emitter to be at full volume
    if (occlusionRayCount > 0)
    {
        float rayThreshold = 0.15f * occlusionRayCount;
        gain += occlusionEnergy / rayThreshold;
    }

    if (permeationRayCount > 0)
    {
        float rayThreshold = 0.15f * permeationRayCount * permeationBounceCount;
        gain += permeationEnergy / rayThreshold;
    }

    return MathF.Min(1, gain);
}

Parameters:

• lowFrequency - indicates whether GainFormula is invoked with low-frequency energy values or high-frequency energy values (GainFormula is invoked twice)
• occlusionRayCount is the number of occlusion rays that were cast by the source emitter
• permeationRayCount is the number of permeation rays that were cast by the source emitter
• permeationBounceCount is the number of bounces per permeation ray
• occlusionEnergy is in the range 0.0 to 1.0, where 1.0 means all occlusion rays discovered the target emitter with maximum energy remaining (i.e. no occlusion)
• permeationEnergy is in the range 0.0 to 1.0, where 1.0 means all permeation rays discovered the target emitter with maximum energy remaining (i.e. all rays passed through air)