Quick tip: supporting wasapi and asio

visual studio
#1

As far as i understand OF0.10 will have unified sound support, where all APIs (Asio, WASAPI, Direct Sound) are enumerated through a single soundStream.getDeviceList() call or the Api can be specified. (see https://github.com/openframeworks/openFrameworks/blob/master/libs/openFrameworks/sound/ofRtAudioSoundStream.cpp#L71)

If you are like me and you already need a choice between different APIs, here is a non-intrusive way to patch OF. The end result will be a exe file that starts with Wasapi, and a Shortcut to the same exe that starts in Asio mode. There will be no changes to your code, so things wonā€™t break if you pass the code to a person that doesnā€™t have the patch, or if you update to a newer version OF.

1. Edit libs/openFrameworks/sound/ofRtAudioSoundStream.cpp

Here we will read the command line arguments to the application and see if ā€œasioā€ was passed as parameter.

Add this just underneath the existing header includes:

#include <wchar.h>
 
bool checkForAsioArgs() {
    LPWSTR *szArgList; 
    int argCount; 
 
    szArgList = CommandLineToArgvW(GetCommandLine(), &argCount);
    if (szArgList != NULL) {
        for (int i = 0; i < argCount; i++) {
            if (wcscmp(szArgList[i], L"asio")==0) {
                return true; 
            }
        }
        LocalFree(szArgList);
    }
    return false; 
}
 
bool of_rtaudiostream_use_asio = checkForAsioArgs(); 
#define OF_RTAUDIO_API (of_rtaudiostream_use_asio?RtAudio::Api::WINDOWS_ASIO:RtAudio::Api::WINDOWS_WASAPI)

Now search for the two occurences of new RtAudio() in that same file.
Replace them with new RtAudio(OF_RTAUDIO_API)

2. Build the solution.

You now have an exe that connects to the WASAPI sound system.

3. Create a shortcut

In windows explorer right click on myApp/bin/myApp.exe and create a new shortcut. Rename it to myApp.exe - Asio so itā€™s easy to find.

Right click on the shortcut and edit the properties. At the end of shortcut target add an ā€˜asioā€™ argument. For me the target is now:

C:\Users\be\Desktop\of_v0.9.3_vs_release\apps\myApps\sketchyscope\bin\sketchyscope.exe asio

Donā€™t worry about the absolute path. Windows should know how to fix things when the folder gets moved around or is copied to another computer.

Andā€¦ thatā€™s all.

Here is a pastebin link with those same instructions which you can add as a comment in your readme or main.cpp: http://pastebin.com/ZZLZ3jUm

1 Like
#2

The feature shoudl already exist in of0.9.3, see here:

And its implmentation:

Still an interesting way of allowing someone to switch Apiā€™s via command line =)

#3

hey.

itā€™s not in 0.9.3.
i saw that it was on master, but look here:


and here

thatā€™s why i made this intermediate solution to have a quick patch, without breaking things once 0.9.4 is out.

best, hansi.

#4

Hello

It seems that this feature is still missing in version 0.9.8 for Visual Studio. Will it be available in the next version of the Visual Studio download?

Thanks

#5

Sorry for the slow response. Iā€™ll look into it.

Had a long hiatus due to grad school but now I have the time to tinker around with OF again.