Waveform generator interface

[HertzDevil]

copied from http://0cc-famitracker.tumblr.com/post/137007965391/a-waveform-generator-interface:

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An interface which exports the following functions: (see fa38a6e)

The wave editor in the tracker will no longer display the preset waveform buttons; instead, right-clicking over the wave editor reveals a "Generate waves..." option, which is a dialog that implements the following:

• A parameter setter function using stWavegenParam;
• A list control to perform the aforementioned functionality;
• A function quantizing the generated floating-point waveforms;
• Optional. Applying a master volume to the generated waveforms, or normalizing all generated waveforms;
• A function applying a clipping behaviour to the generated waveforms;
• Choosing a waveform preset generator;
• Replacing the currently selected waveform with a generated one at a specific tick;
• Optional. Previewing the current waveform selected by the tick as above;
• Optional. Previewing all waveforms; (Waveform generators may not guarantee or enforce any specific wave index sequence)
• Replacing all waveforms with the generated ones (must be supported by the underlying instrument type; N163 only, FDS not yet);
• Optional. Applying a master frequency multiplier to the generated waveforms;
• Optional. Applying a filter to the generated waveforms. (Said feature should belong in the waveform generator itself if desired; loses accuracy since CreateWaves already samples the waveforms)

The tracker should contain at least the following built-in generators:

• Sine, no parameters;
• Triangle, no parameters;
• Sawtooth, no parameters;
• Pulse, with 1 float parameter (pulse width);
• White noise, with 2 integer parameters (tick count, seed).

The tracker should enumerate through DLL files located at the /plugins directory so that third-party developers may include their own waveform generators for all sound chips that support wavetables: N163, FDS, and future extensions.