Wavetable "morph" smoothing lag

[blancoberg]

Bug Description: The wavetable morph parameter has a ~15ms smoothing lag. Compare to other parameters like pitch, the morph parameter lerps to the new value instead of setting in somewhat directly.

Surge XT Version

• Version: 1.3.main.f4c97fc
• Plugin Type: All
• Bitness: 64-bit

Reproduction Steps:

• Select the wavetable oscillator
• Switch to Mono ST mode
• Connect the note modulator to the "Morph" parameter at 100%.
• Play legato notes with c4 and c5 in order to switch between the first and last frame of the wavetable. It should be audible that the wavetable frame position does not switch instantly. It drags behind the note change.
• If you can't hear it, try to disable keytracking and just listen to the glide between the frames.

Removing this line in "WaveTableOscillator.cpp":

float shape = l_shape.v;

And replacing it with this:

float shape = limit_range(localcopy[id_shape].f, 0.f, 1.f); 

Fixes the issue. ( This was suggested by @baconpaul for testing )

Expected Behavior: The morph parameter should change at the same speed as any other parameter, with as little lag as possible.

Computer Information (please complete the following!):

• OS: Windows 10
• Host: Reaper
• Version:

Additional Information:

[blancoberg]

this test is a wavetable that plays a sine wave at 2x speed until it arrives to the last frame where it runs at 1x with any interpolation in between the frames.

How to use the test preset: When playing a legato note between C4 and C5, it should stay on C4. The note should not have time to switch before arriving to the last frame.

Demonstration: https://youtu.be/FxMLi7NjKuc

Morph lag test.zip