Almost all synthesizer code in Piano is removed in favor of the LibDSP
reimplementation.
This causes some issues that mainly have to do with the way Piano
currently handles talking to LibDSP. Additionally, the sampler is gone
for now and will be reintroduced with future work.
This is the first step in transitioning Piano to a full LibDSP backend.
For now, the delay effect is replaced with a (mostly identical)
implementation in LibDSP.
The new ProcessorParameterSlider attaches to a LibDSP::Processor's
range parameter (LibDSP::ProcessorRangeParameter) and changes it
automatically. It also has the ability to update an external GUI::Label.
This is used for the three delay parameters and it will become useful
for auto-generating UI for Processors.
This patch implements a couple of enhancements to the synthesizer
engine:
* Each track has a volume control.
* The input and tooltips for all controls are improved.
* The noise channel is pitched, which allows for basic drum synthesis.
SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
(...and ASSERT_NOT_REACHED => VERIFY_NOT_REACHED)
Since all of these checks are done in release builds as well,
let's rename them to VERIFY to prevent confusion, as everyone is
used to assertions being compiled out in release.
We can introduce a new ASSERT macro that is specifically for debug
checks, but I'm doing this wholesale conversion first since we've
accumulated thousands of these already, and it's not immediately
obvious which ones are suitable for ASSERT.
