v0.1.0 initial commit

render/fade.go

@@ -0,0 +1,47 @@
+package render
+
+import (
+	"time"
+
+	"symph/game"
+	"symph/parameter"
+	"symph/types"
+)
+
+// FadeGrid projects the engine's consumed-note ring onto strip coordinates for
+// one frame: burn-out progress per (y, x, chord-distance). Entries outside the
+// window or past ItemFadeDuration are dropped. A consumed cell at distance 0
+// scrolls off on the next beat; the fade is shorter than the tightest beat, so
+// it always resolves before the strip shifts
+type FadeGrid struct {
+	value [parameter.GamePlayIndexYMax][parameter.GamePlayIndexXMax][game.TileLookaheadMaxWindow]types.Value
+	t     [parameter.GamePlayIndexYMax][parameter.GamePlayIndexXMax][game.TileLookaheadMaxWindow]float64
+}
+
+func (f *FadeGrid) Refresh(s *game.GameState, now time.Time) {
+	*f = FadeGrid{}
+	for _, c := range s.Consumed() {
+		if c.Value == types.ValueNone {
+			continue
+		}
+		age := now.Sub(c.At)
+		if age < 0 || age >= parameter.ItemFadeDuration {
+			continue
+		}
+		d := c.Z - s.CurrentPlayIndexZ
+		if d < 0 || d >= game.TileLookaheadMaxWindow {
+			continue
+		}
+		f.value[c.Y][c.X][d] = c.Value
+		f.t[c.Y][c.X][d] = float64(age) / float64(parameter.ItemFadeDuration)
+	}
+}
+
+// At reports the item burning out at a strip cell and its progress in [0,1)
+func (f *FadeGrid) At(y, x, d int) (types.Value, float64, bool) {
+	if d < 0 || d >= game.TileLookaheadMaxWindow {
+		return types.ValueNone, 0, false
+	}
+	v := f.value[y][x][d]
+	return v, f.t[y][x][d], v != types.ValueNone
+}