Optimize DSP

[pdesaulniers]

The plugin is very CPU-hungry!

[pdesaulniers]

Potential solution:

• Store n points of the graph function in a cache, and linearly interpolate between the points. Then, we'll be able to query the graph more efficiently
• Invalidate the cache when a vertex is moved or the graph is cleared
• TODO: determine how this feature should interact with warp modes. These parameters are smoothed, so the graph function may change at every sample...
  • One option would be to disable the cache while the warp modes are being automated
  • Another option would be to change how the warp modes work. For instance, by applying warp to the samples instead of modifying the graph's function, we wouldn't have to invalidate the cache when warp parameters are modified. Related conversation: Propose a 'Wolf Shaper (Lite)' binary? #116

This would improve the performance of the plugin in the general case. However, this change would not be fully backwards compatible, since it would slightly alter the output of the plugin in existing projects. Whether or not this matters is up for debate.

(But perhaps we could find a way to disable the cache in existing projects, and enable it in newer instances of the plugin?)