JApplet drawPolyLine problem

[memphis_1220]

Hi. I have a problem with an applet that I am creating. It is an oscilloscope but there is one problem. Here is the section of code:

x[i]=i*timeSelection + 250; // x-coordinate calculation
y[i]= offsetIn + (int)(voltsSelection*amplitudeValue*Math.sin(frequencyValue*i));

timeSelection is an integer i.e 10, 100, 1000, in order to stretch the wave when the time/div is changed.
offsetIn is just to move the wave vertically to a particular position.
voltsSelection is the same as timeSelection only stretching it vertically.
amplitudeValue is a value obtained from a JSlider.
frequencyValue is a value obtained from a JSlider.

When I compile and run this code, this is what happens:

Does anyone know why this is happening? Also, when I change the frequency, it seems to just revert back to 0 (flat line) and increases a bit and then back again.

I would really appreciate some input.
Thanks
Mike

 

[ZeroX]

IThe question is, what do YOU expect to see?

Consider this, Math.sin(...) takes RADIANS for it's input argument. Is your frequency value in radians? If you need to convert use Math.toRadians() and Math.toDegrees().

 

[memphis_1220]

Thanks for the reply, but it is now sorted. The timeSelection bit was in the wrong place and the frequency needed to be a double for other features to work.