Fix centering of plasma

Signed-off-by: Martyn Ranyard <m@rtyn.berlin>

cmd/ledcontroller-server/main.go

@@ -26,6 +26,10 @@ var currentEffect queue.QueueItem
 var globalEffectChannel = make(chan queue.QueueItem, 1024)
 var universeCount int = 0
 
+var overrideEffect queue.QueueItem
+var overrideFlag = make(chan queue.QueueItem, 1)
+var previousEffect queue.QueueItem
+
 func foreverLoop() {
 	for /*ever*/ {
 		time.Sleep(40 * time.Millisecond) //25fps
@@ -55,7 +59,7 @@ func main() {
 			}
 		}
 		fmt.Printf("Starting webserver on port %d\n", listenPort)
-		webserver.HandleHTTP(globalEffectChannel, listenPort)
+		webserver.HandleHTTP(globalEffectChannel, listenPort, overrideFlag)
 	}()
 
 	PanelIP := os.Getenv("PANEL_IP")
@@ -113,9 +117,24 @@ func main() {
 	e.Effect = "plasma"
 	e.Speed = 40
 	globalEffectChannel <- e
-
+	e.Effect = "queue"
+	overrideEffect = e
 	go func() {
 		for /*ever*/ {
+			if len(overrideFlag) > 0 {
+				e = <-overrideFlag
+				if e.Effect == "queue" {
+					fmt.Printf("Returning to queue : %s\n", currentEffect.Effect)
+					overrideEffect = e
+					currentEffect = previousEffect
+				} else {
+					fmt.Printf("Overriding with : %s\n", e.Effect)
+					previousEffect = currentEffect
+					overrideEffect = e
+					currentEffect = e
+				}
+			}
+			if overrideEffect.Effect == "queue" {
 				if currentEffect.Duration > 0 {
 					currentEffect.Duration -= 40
 				} else {
@@ -127,6 +146,7 @@ func main() {
 						}
 					}
 				}
+			}
 			var rearranged [][]byte
 			switch currentEffect.Effect {
 			case "line":

internal/patterns/plasma.go

@@ -93,13 +93,14 @@ func PlasmaPanel(w int, h int, speed uint16) [][]RGBcolor {
 	}
 
 	offset := 0.5 // center offset
-	scale := math.Pi * 2.0 / float64(w)
+	scaleW := math.Pi * 2.0 / float64(w)
+	scaleH := math.Pi * 2.0 / float64(h)
 
 	for y := 0; y < h; y++ {
 		for x := 0; x < w; x++ {
-			u := math.Cos((float64(x) + offset) * scale)
-			v := math.Cos((float64(y) + offset) * scale)
-			j := math.Cos(offset * scale) // 2D - No Z
+			u := math.Cos((float64(x) + offset) * scaleW)
+			v := math.Cos((float64(y) + offset) * scaleH)
+			j := math.Cos(offset * scaleW) // 2D - No Z
 			e := (u + v + j + 3.0) / 6.0
 			r, g, b := colorPlasmaFromFloatVal(palletteOffset + e)
 			var rgb [3]byte