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Convert EAX 1.0 parameters to OpenAL EFX EAX parameters?

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I have an old game that uses the old EAX 1.0 reverb parameters for DirectSound:

typedef struct 
unsigned long environment; // 0 to EAX_ENVIRONMENT_COUNT-1
float fVolume; // 0 to 1
float fDecayTime_sec; // seconds, 0.1 to 100
float fDamping; // 0 to 1

I'm rewriting it with OpenAL's EFX EAX extension and I'd need a method to convert the old parameters into the new ones (see below) so that it sounds the same (or as close as possible).

I can use the "environment" member in the old struct to fill in most of the members in the new struct (using the table of pre-defined environments in OpenAL's EFX-util.h), and I guess fVolume and flGain go together (correct?), as well as fDecayTime_sec and flDecayTime. But fDamping doesn't seem to have an obvious correspondence, and I don't know what most of these parameter names actually mean.

Does anyone know how to do this conversion?

This is the new structure:

typedef struct
float flDensity;
float flDiffusion;
float flGain;
float flGainHF;
float flGainLF;
float flDecayTime;
float flDecayHFRatio;
float flDecayLFRatio;
float flReflectionsGain;
float flReflectionsDelay;
float flReflectionsPan[3];
float flLateReverbGain;
float flLateReverbDelay;
float flLateReverbPan[3];
float flEchoTime;
float flEchoDepth;
float flModulationTime;
float flModulationDepth;
float flAirAbsorptionGainHF;
float flHFReference;
float flLFReference;
float flRoomRolloffFactor;
int iDecayHFLimit;



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Also, if anyone could suggest a forum or mailinglist where someone might be more likely to know the answer, that would be appreciated too.

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Hi Momoko Fan, Thanks for the reply. That code seems to be converting from the newer EAXREVERBPROPERTIES structure (I guess since it is defined as float[28] which matches size, and the code looks right too). I need to convert from the small structure described in the OP.

I did find this: http://icculus.org/~taylor/fso/misc/new-sound-3_6_12.diff, which confirms fVolume<=>flGain and fDecayTime_sec<=>flDecayTime. It also assigns fDamping directly into flDecayHFRatio, but I'm not sure if this is correct because it still sounds a bit different than it does under dsound.

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