Generating sound with frequency modulation

In this recipe, we will learn how to modulate a sine wave oscillator using another low frequency sine wave.

We will be basing this recipe on the previous recipe, where the y position of the mouse controlled the frequency of the sine wave; in this recipe, we will use the x position of the mouse to control the modulation frequency.

Getting ready

We will be using the code from the previous recipe, Generating a sine oscillator.

How to do it…

We will multiply the sine wave created in the previous recipe with another low frequency sine wave.

1. Add the following member variables:

   float mModFrequency;
   float mModPhase, mModPhaseAdd;

2. Add the following in the setup module to initialize the variables created previously:

   mModFrequency = 0.0f;
   mModPhase = 0.0f;
   mModPhaseAdd = 0.0f;

3. In the update module, add the following code to calculate the modulation frequency based on the x position of the mouse cursor:

   float maxModFrequency= 30.0f;
   float targetModFrequency= ( getMousePos...