[openal] Where can I find the enum parameters that these functions accept: GetEffectf/fv-GetEffecti/iv GetFilteri/iv-GetFilterif/fv, GetAuxiliary...

Sean s.tolstoyevski at gmail.com
Sat Jul 31 01:26:14 EDT 2021

The SDK document is too old.

No new enum parameters added to Effects?

Thanks you for your detailed answer.

On 29/07/2021 11:14, Chris Robinson wrote:
> On Thu, 29 Jul 2021 09:08:21 +0300
> Sean <s.tolstoyevski at gmail.com> wrote:
>> Hello there,
>> I've been reviewing the OpenAL-Soft source for a long time.
>> I couldn't find any parameters that these functions can accept.
> This is detailed in the Effects Extension Guide PDF. It's part of the
> Core SDK download on openal.org, or if you don't have Windows to
> install it, it can be downloaded separately from here:
> https://openal-soft.org/misc-downloads/Effects%20Extension%20Guide.pdf
>> Looking at the overall code structure of OpenAL-Soft, *param* is
>> evaluated in the switch statement.
>> Like alGetSourcef.
>> By examining these codes, I can tell if I'm doing the right things.
>> But I couldn't find anything in the source code for effects, filters
>> and AuxiliarySends.
>> Where exactly are these defined in OpenAL-Soft?
> By default, the only parameter an effect can set is AL_EFFECT_TYPE, of
> which the available values are AL_EFFECT_NULL, AL_EFFECT_EAXREVERB,
> AL_EFFECT_REVERB, AL_EFFECT_CHORUS, and others. Which effects are
> available is implementation-dependent, so for example some may not allow
> you to set a Chorus effect if it's not implemented. OpenAL Soft
> supports all of those standard effect types.
> Once an effect type is set, then the alEffect* functions can accept
> other parameters relating to that effect. So if you call
> and it succeeds, you can then call
> alEffectf(effect, AL_EAXREVERB_DENSITY, density);
> alEffectf(effect, AL_EAXREVERB_DIFFUSION, diffusion);
> ...etc...
> to set the reverb effect parameters. When you change the effect type,
> for example by calling
> alEffecti(effect, AL_EFFECT_TYPE, AL_EFFECT_CHORUS);
> the reverb parameters are cleared and you can now set the chorus effect
> parameters:
> alEffecti(effect, AL_CHORUS_WAVEFORM, waveform);
> ...etc...
> The EFX-standard effect types, and their parameters, are described in
> the above-linked guide. OpenAL Soft comes with an efx-presets.h header,
> which defines a number of reverb presets that can be assigned to
> effects.
> Filters are similar. By default, only the AL_FILTER_TYPE property can
> be set, of which there's AL_FILTER_NULL, AL_FILTER_LOWPASS,
> AL_FILTER_HIGHPASS, and AL_FILTER_BANDPASS types. Set one of the filter
> types, then you can set that type's properties. The guide explains what
> properties are available for the different types.
> AuxiliaryEffectSlots are more typical objects, which have a set
> predefined number of properties that can be set. An effect can be set
> on one, and sources can be connected to one to have the given effect
> apply to the given sources.
>> In particular, I cannot understand how vector functions work.
> The vector functions are how properties that need multiple values can
> be given them. All single-value properties (e.g. AL_EFFECT_TYPE) can be
> set through the single-value or array/vector functions. For example,
> // and
> ALint type[1] = { AL_EFFECT_EAXREVERB };
> alEffectiv(effect, AL_EFFECT_TYPE, type);
> have the same result. However, some properties require multiple values
> and can only be used with the array/vector functions, like
> AL_EAXREVERB_REFLECTIONS_PAN which needs three values to specify a
> direction and magnitude:
> ALfloat pan[3] = { x, y, z };
> alEffectfv(effect, AL_EAXREVERB_REFLECTIONS_PAN, pan);
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