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feat(vm): add support for gm.dls samples in the go virtual machine (closes #75)

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This commit is contained in:
5684185+vsariola@users.noreply.github.com
2023-08-28 22:44:37 +03:00
parent 6ec06c760a
commit 7dd2c246a0
4 changed files with 78 additions and 36 deletions
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96
vm/interpreter.go
View File

@ -1,9 +1,12 @@
package vm
import (
"encoding/binary"
"errors"
"fmt"
"math"
"os"
"path/filepath"
"github.com/vsariola/sointu"
)
@ -63,6 +66,27 @@ const (
envStateRelease
)
var su_sample_table [3440660]byte
func init() {
var f *os.File
var err error
if f, err = os.Open("gm.dls"); err == nil { // try to open from current directory first
goto success
}
if f, err = os.Open(filepath.Join(os.Getenv("SystemRoot"), "system32", "drivers", "gm.dls")); err == nil {
goto success
}
if f, err = os.Open(filepath.Join(os.Getenv("SystemRoot"), "SysWOW64", "drivers", "gm.dls")); err == nil {
goto success
}
return
success:
defer f.Close()
// read file, ignoring errors
f.Read(su_sample_table[:])
}
func Synth(patch sointu.Patch, bpm int) (sointu.Synth, error) {
bytePatch, err := Encode(patch, AllFeatures{}, bpm)
if err != nil {
@ -429,37 +453,53 @@ func (s *Interpreter) Render(buffer []float32, maxtime int) (samples int, time i
} else {
omega *= 0.000038 // pretty random scaling constant to get LFOs into reasonable range. Historical reasons, goes all the way back to 4klang
}
*statevar += float32(omega)
*statevar -= float32(int(*statevar+1) - 1)
phase := *statevar
phase += params[2]
phase -= float32(int(phase))
color := params[3]
var amplitude float32
switch {
case flags&0x40 == 0x40: // Sine
if phase < color {
amplitude = float32(math.Sin(2 * math.Pi * float64(phase/color)))
*statevar += float32(omega)
if flags&0x80 == 0x80 { // if this is a sample oscillator
phase := *statevar
phase += params[2]
sampleno := valuesAtTransform[3] // reuse color as the sample number
sampleoffset := s.bytePatch.SampleOffsets[sampleno]
sampleindex := int(phase*84.28074964676522 + 0.5)
loopstart := int(sampleoffset.LoopStart)
if sampleindex >= loopstart {
sampleindex -= loopstart
sampleindex %= int(sampleoffset.LoopLength)
sampleindex += loopstart
}
case flags&0x20 == 0x20: // Trisaw
if phase >= color {
phase = 1 - phase
color = 1 - color
sampleindex += int(sampleoffset.Start)
amplitude = float32(int16(binary.LittleEndian.Uint16(su_sample_table[sampleindex*2:]))) / 32767.0
} else {
*statevar -= float32(int(*statevar+1) - 1)
phase := *statevar
phase += params[2]
phase -= float32(int(phase))
color := params[3]
switch {
case flags&0x40 == 0x40: // Sine
if phase < color {
amplitude = float32(math.Sin(2 * math.Pi * float64(phase/color)))
}
case flags&0x20 == 0x20: // Trisaw
if phase >= color {
phase = 1 - phase
color = 1 - color
}
amplitude = phase/color*2 - 1
case flags&0x10 == 0x10: // Pulse
if phase >= color {
amplitude = -1
} else {
amplitude = 1
}
case flags&0x4 == 0x4: // Gate
maskLow, maskHigh := valuesAtTransform[3], valuesAtTransform[4]
gateBits := (int(maskHigh) << 8) + int(maskLow)
amplitude = float32((gateBits >> (int(phase*16+.5) & 15)) & 1)
g := unit.state[4+i] // warning: still fucks up with unison = 3
amplitude += 0.99609375 * (g - amplitude)
unit.state[4+i] = amplitude
}
amplitude = phase/color*2 - 1
case flags&0x10 == 0x10: // Pulse
if phase >= color {
amplitude = -1
} else {
amplitude = 1
}
case flags&0x4 == 0x4: // Gate
maskLow, maskHigh := valuesAtTransform[3], valuesAtTransform[4]
gateBits := (int(maskHigh) << 8) + int(maskLow)
amplitude = float32((gateBits >> (int(phase*16+.5) & 15)) & 1)
g := unit.state[4+i] // warning: still fucks up with unison = 3
amplitude += 0.99609375 * (g - amplitude)
unit.state[4+i] = amplitude
}
if flags&0x4 == 0 {
output += waveshape(amplitude, params[4]) * params[5]

4
vm/interpreter_test.go
View File

@ -28,8 +28,8 @@ func TestAllRegressionTests(t *testing.T) {
basename := filepath.Base(filename)
testname := strings.TrimSuffix(basename, path.Ext(basename))
t.Run(testname, func(t *testing.T) {
if strings.Contains(testname, "sample") {
t.Skip("Samples (gm.dls) not available in the interpreter VM at the moment")
if runtime.GOOS != "windows" && strings.Contains(testname, "sample") {
t.Skip("Samples (gm.dls) available only on Windows")
return
}
asmcode, err := ioutil.ReadFile(filename)