This commit adds basic support for importing, viewing and playing WAV
samples at different pitches.
Naming issues:
- We are using the Sample struct from Music.h, but also the Sample
struct from LibAudio (Audio::Sample). This is a little confusing.
set_recorded_sample() finds the peak sample and then divides all the
samples by that peak to get a guaranteed min/max of -1/1. This is nice
because our other waves are also bound between these values and we can
just do the same stuff. This is why we're using Audio::Sample, because
it uses floats, whereas Music.h's Sample uses i16s. It's a little
annoying that we have to use a mixture of floats and doubles though.
For playback at lower frequencies, we're calculating in-between samples,
rather than just playing samples multiple times. Basically, you get the
current sample and add the difference between the current sample and the
next sample multiplied by the distance from the current sample. This is
like drawing the hypotenuse of a right-angled triangle.
This is not a bug currently, since the first column immediately starts
playing at startup and leaves no time for the user to put notes in it.
However, this is needed for exporting.
The piano roll data definitely belongs in AudioEngine along with the
note and time data. Now RollWidget only has GUI information, much like
the other widgets.
Note that this commit exacerbates issue #1158 which is caused by
RollWidget::paint_event().
Notice that we are calculating release time according to the level when
the note is turned off rather than the sustain level. Naively using the
sustain level gives very long release times if you turn the note off
during attack, whereas this deterministically gives the same release
time.
1. Make decay sample-granular rather than buffer-granular
You only have ~43 buffers per second which can make a jagged signal.
2. Calculate decay in milliseconds
Decay is supposed to be a time value.
I say "phony" because it's not actually playing the same frequency
twice, it's just playing the same frequency at a higher volume. We can
properly implement this later but at the moment it'll get in the way of
our ADSR implementation.
Goals:
- Switch to a more typical LibGUI arrangement
- Separate GUI (MainWidget) and audio (AudioEngine)
- Improve on existing features while retaining the same feature set
Improvements:
- Each GUI element is a separate widget
- The wave (WaveWidget) scales with the window
- The piano roll (RollWidget) scales horizontally and scrolls vertically
- The piano (KeysWidget) fits as many notes as possible
- The knobs (KnobsWidget) are now sliders
- All mouse and key events are handled in constant time
- The octave can be changed while playing notes
- The same note can be played with the mouse, keyboard and roll at the
same time, and the volume of the resulting note is scaled accordingly
- Note frequency constants use the maximum precision available in a
double
