Play sine wave

cpper

Good evening :)
I'm looking for a method to play a sine wave, or whatever tone, at a specific frequency ? How could I achieve this ?

? Offline

Hi! AFAIK, our framework doesn't provide such low-level audio stuff.

cpper

That's strange. Meanwhile I found this post but I'm not sure what happens there, there's too much maths. I'll take a deeper look though.
Thanks :)

SGaist

Hi,

The sine wave generation is indeed out of Qt's scope, however you can use QAudioOutput to send the data to your sound card.

JKSH

@cpper said in Play sine wave:

I found this post but I'm not sure what happens there, there's too much maths.

The maths is for calculating the values of different samples in a digital sine wave.

Let's say you take a single cycle of a sine wave, and split it into N samples. The simplest way to generate this wave is:

double samples[N];
for (int n = 0; n < N; ++n)
    samples[n] = sin( 2*PI * n/N );

For example, if you want to split your wave cycle into 1000 samples, then N = 1000 and

samples[  0] = sin( 2*PI *   0/1000 );
samples[  1] = sin( 2*PI *   1/1000 );
samples[  2] = sin( 2*PI *   2/1000 );
...
samples[997] = sin( 2*PI * 997/1000 );
samples[998] = sin( 2*PI * 998/1000 );
samples[999] = sin( 2*PI * 999/1000 );

That's it, you now have an array of samples that represents one cycle of a sine wave.

mostefa

Hi @cpper

One original way can be to use QML and shadereffect (only if you have to use QML , and have knowledge in GPU programming)

http://doc.qt.io/qt-5/qml-qtquick-shadereffect.html

You can use this shader effect for example

http://glslsandbox.com/e#36864.2

You can have a look at this link :

http://stackoverflow.com/questions/27118049/qml-need-idea-how-to-animate-waves

and this link :

http://qmlbook.github.io/ch09/index.html

But for me shaders are not simple and intuitive ,

And i don't even know if what I propose is recommended...

JKSH

@mostefa said in Play sine wave:

Hi @cpper

One original way can be to use QML and shadereffect (only if you have to use QML , and have knowledge in GPU programming)

http://doc.qt.io/qt-5/qml-qtquick-shadereffect.html

You can use this shader effect for example

http://glslsandbox.com/e#36864.2

You can have a look at this link :

http://stackoverflow.com/questions/27118049/qml-need-idea-how-to-animate-waves

and this link :

http://qmlbook.github.io/ch09/index.html

But for me shaders are not simple and intuitive ,

And i don't even know if what I propose is recommended...

I believe @cpper is asking about sound waves, not graphical waves

mostefa

@JKSH said in Play sine wave:

@mostefa said in Play sine wave:

Hi @cpper

One original way can be to use QML and shadereffect (only if you have to use QML , and have knowledge in GPU programming)

http://doc.qt.io/qt-5/qml-qtquick-shadereffect.html

You can use this shader effect for example

http://glslsandbox.com/e#36864.2

You can have a look at this link :

http://stackoverflow.com/questions/27118049/qml-need-idea-how-to-animate-waves

and this link :

http://qmlbook.github.io/ch09/index.html

But for me shaders are not simple and intuitive ,

And i don't even know if what I propose is recommended...

I believe @cpper is asking about sound waves, not graphical waves

Ah , i think that you are right , sorry !