reverse working and alternating pattern added

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

main.go

@@ -8,17 +8,45 @@ import (
 	"github.com/Hundemeier/go-sacn/sacn"
 )
 
+func even(number int) bool {
+    return number%2 == 0
+}
+
 func slice_rearrange(rowwidth int, rows int, alternaterows bool, inslice []byte) [][]byte {
+	var flippedslice []byte
 	if alternaterows {
-		panic("Alternating rows not yet implemented")
+		flippedslice = make([]byte, len(inslice)+3)
+		for r := 0; r < rows; r++ {
+			rowzero := (r*rowwidth*3)
+			if even(r) {
+				for c := 0; c < (rowwidth)*3; c+=3 {
+					flippedslice[rowzero+c] = inslice[rowzero+c]
+					flippedslice[rowzero+c+1] = inslice[rowzero+c+1]
+					flippedslice[rowzero+c+2] = inslice[rowzero+c+2]
+				}
+			} else {
+				x := rowwidth*3
+				for c := 0; c < (rowwidth)*3; c+=3 {
+					x = x-3
+					fmt.Println(x)
+					flippedslice[rowzero+x] = inslice[rowzero+c]
+					flippedslice[rowzero+x+1] = inslice[rowzero+c+1]
+					flippedslice[rowzero+x+2] = inslice[rowzero+c+2]/*
+					flippedslice[rowzero+c] = inslice[rowzero+(((rowwidth-1)*3)-c)]
+					flippedslice[rowzero+c+1] = inslice[rowzero+(((rowwidth-1)*3)-c)-1]
+					flippedslice[rowzero+c+2] = inslice[rowzero+(((rowwidth-1)*3)-c)-2]*/
+				}
+			}
+		}
+	} else {
+		flippedslice = inslice
 	}
 	currentUniverse := 0
 	currentUniversePosition := 0
-	universes := make([][]byte, (len(inslice)/510)+1)
+	universes := make([][]byte, (len(flippedslice)/510)+1)
 	currentUniverseSlice := make([]byte, 511)
 	currentRowReverse := false;
-	for i := range(inslice) {
+	for i := range(flippedslice) {
-		fmt.Println(i)
 		if currentUniversePosition >= 510 {
 			fmt.Println("Reached end of universe!")
 			universes[currentUniverse] = currentUniverseSlice
@@ -31,13 +59,29 @@ func slice_rearrange(rowwidth int, rows int, alternaterows bool, inslice []byte)
 			currentUniversePosition = 0
 			currentUniverseSlice = make([]byte, 511)
 		}
-		currentUniverseSlice[currentUniversePosition] = inslice[i]
+		currentUniverseSlice[currentUniversePosition] = flippedslice[i]
 		currentUniversePosition += 1
 	}
 	universes[currentUniverse] = currentUniverseSlice
   	return universes
 }
 
+func alternate(R0 byte, G0 byte, B0 byte, R1 byte, G1 byte, B1 byte, fromX int, toX int) []byte {
+	ret := make([]byte, toX*3);
+	for i := fromX; i < toX*3; i+=3 {
+		if even(i) {
+			ret[i] = R0
+			ret[i+1] = G0
+			ret[i+2] = B0
+		} else {
+			ret[i] = R1
+			ret[i+1] = G1
+			ret[i+2] = B1
+		}
+	}
+    return ret
+}
+
 // gradient returns from fromX to toX fading from (fromR,fromG,fromB) to (toR,toG,toB)
 // at least that's the idea.
 func gradient(fromR byte, fromG byte, fromB byte, toR byte, toG byte, toB byte, fromX int, toX int) []byte {
@@ -64,7 +108,7 @@ func slice512(s []byte) [512]byte {
 }
 
 func sliceUnlenthed(s [512]byte) []byte {
-	ret := make([]byte, 512);
+	ret := make([]byte, 512)
 	for i := range(s) {
 		ret[i] = s[i]
 	}
@@ -102,7 +146,7 @@ func main() {
 	
 	//send some random data for 10 seconds
 	for i := 0; i < 20; i++ {
-		channels := slice_rearrange(68,4,false,gradient(0,0,255,255,0,0,0,272))
+		channels := slice_rearrange(68,4,true,gradient(255,255,255,0,0,0,0,272))
 		ch1 <- slice512(channels[0])
 		ch2 <- slice512(channels[1])
 		time.Sleep(500 * time.Millisecond)