Working plasma pattern

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

cmd/ledcontroller-server/main.go

@@ -24,11 +24,12 @@ var sema = make(chan struct{}, 1) // a binary semaphore guarding currentFrame
 
 var currentEffect queue.QueueItem
 var globalEffectChannel = make(chan queue.QueueItem, 1024)
+var universeCount int = 0
 
 func foreverLoop() {
 	for /*ever*/ {
 		time.Sleep(40 * time.Millisecond) //25fps
-		for u := 0; u < 2; u++ {
+		for u := 0; u < universeCount; u++ {
 			sema <- struct{}{} // acquire token
 			channels[u] <- currentFrame[u]
 			<-sema
@@ -43,8 +44,6 @@ func reduceBrightness(universe [512]byte, percentage int) [512]byte {
 	return universe
 }
 
-var universeCount int = 0
-
 func main() {
 	go func() {
 		var err error
@@ -74,7 +73,7 @@ func main() {
 	}
 
 	universeCount = int(math.Ceil(float64(PanelHeight*PanelWidth*3) / 510))
-	fmt.Printf("Universe count is %d", universeCount)
+	fmt.Printf("Universe count is %d\n", universeCount)
 
 	PanelBrightness, err := strconv.Atoi(os.Getenv("PANEL_BRIGHTNESS"))
 	if err != nil {
@@ -111,7 +110,8 @@ func main() {
 	e.SeedColour[1] = 255
 	e.SeedColour[2] = 0
 	globalEffectChannel <- e
-	e.Effect = "default"
+	e.Effect = "plasma"
+	e.Speed = 40
 	globalEffectChannel <- e
 
 	go func() {
@@ -120,7 +120,11 @@ func main() {
 				currentEffect.Duration -= 40
 			} else {
 				if len(globalEffectChannel) > 0 {
+					lastEffect := currentEffect
 					currentEffect = <-globalEffectChannel
+					if lastEffect != currentEffect {
+						fmt.Printf("New effect selected : %s\n", currentEffect.Effect)
+					}
 				}
 			}
 			var rearranged [][]byte

internal/patterns/plasma.go

@@ -1,9 +1,15 @@
 package patterns
 
-import "math"
+import (
+	"math"
+)
 
 type RGBcolor = [3]byte
 
+func floatColorToIntColor(val float64) byte {
+	return byte(val*256 - 0.5)
+}
+
 func plasmaRGBFromVal(val byte) (byte, byte, byte) {
 	var r byte
 	var g byte
@@ -24,7 +30,6 @@ func plasmaRGBFromVal(val byte) (byte, byte, byte) {
 	return r, g, b
 }
 
-
 func LinearPlasma(l int) []byte {
 	line := make([]byte, l*3)
 	for i := 0; i < l*3; i += 3 {
@@ -37,26 +42,66 @@ func LinearPlasma(l int) []byte {
 	return line
 }
 
-var offset float64 = 0.5
+func linearFromVal(val byte) (byte, byte, byte) {
+	var r byte = val
+	var g byte = 0
+	var b byte = 0
+	return r, g, b
+}
+
+func positiveModF(val float64) float64 {
+	_, val = math.Modf(val)
+	if val < 0 {
+		return val + 1.0
+	}
+	return val
+}
+
+func colorPlasmaFromFloatVal(val float64) (byte, byte, byte) {
+	var r byte
+	var g byte
+	var b byte
+	val = positiveModF(val) * 3.0
+	if val < 1.0 {
+		r = floatColorToIntColor(val)
+		g = floatColorToIntColor(1.0 - val)
+		b = 0
+	} else if val < 2.0 {
+		b = floatColorToIntColor(val - 1.0)
+		r = floatColorToIntColor(1.0 - (val - 1.0))
+		g = 0.0
+	} else {
+		g = floatColorToIntColor(val - 2.0)
+		b = floatColorToIntColor(1.0 - (val - 2.0))
+		r = 0.0
+	}
+	return r, g, b
+}
+
+var palletteOffset float64 = 0.0
 
 func PlasmaPanel(w int, h int, speed uint16) [][]RGBcolor {
 	grid := make([][]RGBcolor, w)
 	for i := 0; i < w; i++ {
 		grid[i] = make([]RGBcolor, h)
 	}
-	scale := math.Pi * 2.0 / float64(w)
+
-	step := float64(5 * speed / 40)
+	// pbrook didn't say what DT is for... so it resolves to 0.05
-	offset -= step
+	palletteOffset -= 0.05 / 1.0
-	if offset < 0 {
+	if palletteOffset < 0 {
-		offset += 1.0
+		palletteOffset += 1.0
 	}
+
+	offset := 0.5 // center offset
+	scale := math.Pi * 2.0 / float64(w)
+
 	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)
-			w := math.Cos((float64(w) + offset) * scale)
+			j := math.Cos(offset * scale) // 2D - No Z
-			e := (u + v + w + 3.0) / 6.0
+			e := (u + v + j + 3.0) / 6.0
-			r, g, b := plasmaRGBFromVal(byte((offset + e) * 255))
+			r, g, b := colorPlasmaFromFloatVal(palletteOffset + e)
 			var rgb [3]byte
 			rgb[0] = r
 			rgb[1] = g
@@ -65,4 +110,4 @@ func PlasmaPanel(w int, h int, speed uint16) [][]RGBcolor {
 		}
 	}
 	return grid
-}
+}

internal/webserver/webserver.go

@@ -1,18 +1,17 @@
 package webserver
 
 import (
-
+	queue "git.martyn.berlin/martyn/LEDController/internal/queue"
 	"github.com/gorilla/handlers"
 	"github.com/gorilla/mux"
-	queue "git.martyn.berlin/martyn/LEDController/internal/queue"
 	"golang.org/x/image/colornames"
 
 	"fmt"
 	"net/http"
 	"os"
-	"time"
 	"strconv"
 	"strings"
+	"time"
 )
 
 func HealthHandler(response http.ResponseWriter, request *http.Request) {
@@ -30,7 +29,7 @@ func RootHandler(response http.ResponseWriter, request *http.Request) {
 	fmt.Fprint(response, "Not implemented")
 }
 
-var globalQueue chan queue.QueueItem;
+var globalQueue chan queue.QueueItem
 
 func PatternHandler(response http.ResponseWriter, request *http.Request) {
 	vars := mux.Vars(request)
@@ -68,7 +67,7 @@ func ColourHandler(response http.ResponseWriter, request *http.Request) {
 		e.Duration = 5000
 	}
 	var c queue.RGBcolor
-	for cn, cv := range(colornames.Map) {
+	for cn, cv := range colornames.Map {
 		if cn == strings.ToLower(vars["name"]) {
 			c[0] = cv.R
 			c[1] = cv.G
@@ -93,7 +92,7 @@ func FadeHandler(response http.ResponseWriter, request *http.Request) {
 		e.Duration = 5000
 	}
 	var c queue.RGBcolor
-	for cn, cv := range(colornames.Map) {
+	for cn, cv := range colornames.Map {
 		if cn == strings.ToLower(vars["namefrom"]) {
 			c[0] = cv.R
 			c[1] = cv.G
@@ -101,7 +100,7 @@ func FadeHandler(response http.ResponseWriter, request *http.Request) {
 		}
 	}
 	e.SeedColour = c
-	for cn, cv := range(colornames.Map) {
+	for cn, cv := range colornames.Map {
 		if cn == strings.ToLower(vars["nameto"]) {
 			c[0] = cv.R
 			c[1] = cv.G
@@ -132,7 +131,7 @@ func HandleHTTP(queueChannel chan queue.QueueItem, Port int) {
 	http.Handle("/", r)
 	srv := &http.Server{
 		Handler:      loggedRouter,
-		Addr:         "0.0.0.0:"+strconv.Itoa(Port),
+		Addr:         "0.0.0.0:" + strconv.Itoa(Port),
 		WriteTimeout: 15 * time.Second,
 		ReadTimeout:  15 * time.Second,
 	}