drafting

tracker/stack.go

@@ -0,0 +1,84 @@
+package tracker
+
+import (
+	"fmt"
+
+	"github.com/vsariola/sointu"
+)
+
+type (
+	SignalRail struct {
+		signals [][]Signal
+		scratch []signalScratch
+	}
+
+	signalScratch struct {
+		instr, unit int
+	}
+
+	Signal struct {
+		PassThrough int
+		StackUse    sointu.StackUse
+	}
+
+	SignalRailType Model
+)
+
+func (m *Model) SignalRail() *SignalRailType {
+	return (*SignalRailType)(m)
+}
+
+func (s *SignalRailType) Item(u int) Signal {
+	i := s.d.InstrIndex
+	if i < 0 || u < 0 || i >= len(s.derived.rail.signals) || u >= len(s.derived.rail.signals[i]) {
+		return Signal{}
+	}
+	return s.derived.rail.signals[i][u]
+}
+
+func (s *SignalRail) update(patch sointu.Patch) (err error) {
+	s.scratch = s.scratch[:0]
+	for i, instr := range patch {
+		for len(s.signals) <= i {
+			s.signals = append(s.signals, make([]Signal, len(instr.Units)))
+		}
+		start := len(s.scratch)
+		for u, unit := range instr.Units {
+			for len(s.signals[i]) <= i {
+				s.signals[i] = append(s.signals[i], Signal{})
+			}
+			stackUse := unit.StackUse()
+			numInputs := len(stackUse.Inputs)
+			if len(s.scratch) < numInputs && err != nil {
+				err = fmt.Errorf("%s unit in instrument %d / %s needs %d inputs, but got only %d", unit.Type, i, instr.Name, numInputs, len(s.scratch))
+				s.scratch = s.scratch[:0]
+			} else {
+				s.scratch = s.scratch[:len(s.scratch)-numInputs]
+			}
+			s.signals[i][u] = Signal{
+				PassThrough: len(s.scratch),
+				StackUse:    stackUse,
+			}
+			for _ = range stackUse.NumOutputs {
+				s.scratch = append(s.scratch, signalScratch{instr: i, unit: u})
+			}
+		}
+		diff := len(s.scratch) - start
+		if instr.NumVoices > 1 && diff != 0 {
+			if diff < 0 {
+				morepop := (instr.NumVoices - 1) * diff
+				if morepop > len(s.scratch) && err != nil {
+					err = fmt.Errorf("each voice of instrument %d / %s consumes %d signals, but there was not enough signals available", i, instr.Name, -diff)
+					s.scratch = s.scratch[:0]
+				} else {
+					s.scratch = s.scratch[:len(s.scratch)-morepop]
+				}
+			} else {
+				for range (instr.NumVoices - 1) * diff {
+					s.scratch = append(s.scratch, s.scratch[len(s.scratch)-diff])
+				}
+			}
+		}
+	}
+	return err
+}