feat(tracker): add simple instrument editor

tracker/instruments.go

@@ -0,0 +1,121 @@
+package tracker
+
+import (
+	"fmt"
+	"sort"
+
+	"gioui.org/layout"
+	"gioui.org/widget"
+	"gioui.org/widget/material"
+)
+
+type C = layout.Context
+type D = layout.Dimensions
+
+func (t *Tracker) updateInstrumentScroll() {
+	if t.CurrentInstrument > 7 {
+		t.InstrumentList.Position.First = t.CurrentInstrument - 7
+	} else {
+		t.InstrumentList.Position.First = 0
+	}
+}
+
+func (t *Tracker) layoutInstruments() layout.Widget {
+	return func(gtx C) D {
+		return layout.Flex{Axis: layout.Vertical}.Layout(gtx,
+			layout.Rigid(t.layoutInstrumentNames()),
+			layout.Flexed(1, t.layoutInstrumentEditor()))
+	}
+}
+
+func (t *Tracker) layoutInstrumentNames() layout.Widget {
+	return func(gtx C) D {
+		count := len(t.song.Patch.Instruments)
+		if len(t.InstrumentBtns) < count {
+			tail := make([]*widget.Clickable, count-len(t.InstrumentBtns))
+			for t := range tail {
+				tail[t] = new(widget.Clickable)
+			}
+			t.InstrumentBtns = append(t.InstrumentBtns, tail...)
+		}
+		return t.InstrumentList.Layout(gtx, count, func(gtx C, index int) D {
+			for t.InstrumentBtns[index].Clicked() {
+				t.CurrentInstrument = index
+			}
+			btnStyle := material.Button(t.Theme, t.InstrumentBtns[index], fmt.Sprintf("%v", index))
+			btnStyle.Background = transparent
+			return btnStyle.Layout(gtx)
+		})
+	}
+}
+func (t *Tracker) layoutInstrumentEditor() layout.Widget {
+	return func(gtx C) D {
+		return layout.Flex{Axis: layout.Horizontal}.Layout(gtx,
+			layout.Rigid(t.layoutUnitList()),
+			layout.Rigid(t.layoutUnitControls()))
+	}
+}
+
+func (t *Tracker) layoutUnitList() layout.Widget {
+	return func(gtx C) D {
+		units := t.song.Patch.Instruments[t.CurrentInstrument].Units
+		count := len(units)
+		if len(t.UnitBtns) < count {
+			tail := make([]*widget.Clickable, count-len(t.UnitBtns))
+			for t := range tail {
+				tail[t] = new(widget.Clickable)
+			}
+			t.UnitBtns = append(t.UnitBtns, tail...)
+		}
+		children := make([]layout.FlexChild, len(t.song.Patch.Instruments[t.CurrentInstrument].Units))
+		for i, u := range t.song.Patch.Instruments[t.CurrentInstrument].Units {
+			for t.UnitBtns[i].Clicked() {
+				t.CurrentUnit = i
+			}
+			btnStyle := material.Button(t.Theme, t.UnitBtns[i], u.Type)
+			btnStyle.Background = transparent
+			children[i] = layout.Rigid(btnStyle.Layout)
+		}
+		return layout.Flex{Axis: layout.Vertical}.Layout(gtx, children...)
+	}
+}
+
+func (t *Tracker) layoutUnitControls() layout.Widget {
+	return func(gtx C) D {
+		params := t.song.Patch.Instruments[t.CurrentInstrument].Units[t.CurrentUnit].Parameters
+		count := len(params)
+		children := make([]layout.FlexChild, 0, count)
+		if len(t.ParameterSliders) < count {
+			tail := make([]*widget.Float, count-len(t.ParameterSliders))
+			for t := range tail {
+				tail[t] = new(widget.Float)
+			}
+			t.ParameterSliders = append(t.ParameterSliders, tail...)
+		}
+		keys := make([]string, 0, len(params))
+		for k := range params {
+			keys = append(keys, k)
+		}
+		sort.Strings(keys)
+		for i, k := range keys {
+			for t.ParameterSliders[i].Changed() {
+				params[k] = int(t.ParameterSliders[i].Value)
+				// TODO: tracker should have functions to update parameters and
+				// to do this efficiently i.e. not compile the whole patch again
+				t.LoadSong(t.song)
+			}
+			t.ParameterSliders[i].Value = float32(params[k])
+			sliderStyle := material.Slider(t.Theme, t.ParameterSliders[i], 0, 128)
+			k2 := k // avoid k changing in the closure
+			children = append(children, layout.Rigid(func(gtx C) D {
+				return layout.Flex{Axis: layout.Horizontal}.Layout(gtx,
+					layout.Rigid(Label(k2, white)),
+					layout.Rigid(func(gtx C) D {
+						gtx.Constraints.Min.X = 200
+						return sliderStyle.Layout(gtx)
+					}))
+			}))
+		}
+		return layout.Flex{Axis: layout.Vertical}.Layout(gtx, children...)
+	}
+}