Is OpenGL faster than JUCE graphics?

#1

Hi,
I’ve been having some trouble displaying an FFT using various drawing functions like paths and drawLine(). This has got me curious about OpenGL and whether that might be better? I think I read somewhere that it was faster, is that the case? Alternatively, is there a better way to use Juce graphics? This is my drawing loop:

              for (int r = 0; dr < f1.fftSize/2; r++)
           {

               g.setColour(Colours::thistle);
   
               g.setOpacity(0.9);

               g.drawLine(logScale[r], 300, logScale[r], outC[r], 2);

            }

(outC is the fft result and fftSize = 8192)
When I use paths the plugin just completely freezes, and with drawLine() its just slow.
Is there a better way?
Thanks!

#2

If you write your own shaders it’s definitely going to be a whole lot faster. Simplest way would be to send the FFT amplitude points to a geometry shader and use that to create the “curve” shape of the display.

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#3

you can set colour and opacity before the loop if you don’t plan to change it dynamically with the measured data or something

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