add initial randoffset mode

main.go

@@ -69,7 +69,8 @@ func main() {
 			// run RPC server, tasking clients to flut
 			wg.Add(1)
 			r := rpc.SummonRán(*ránAddr, stopChan, &wg)
-			r.SetTask(img, offset, *address, *connections) // @incomplete
+			// TODO: startup without a task, but init params
+			r.SetTask(img, offset, *address, *connections)
 
 		} else {
 			// fetch server state and save to file
@@ -82,7 +83,7 @@ func main() {
 
 			// local 🌊🌊🌊🌊🌊🌊🌊🌊🌊🌊🌊🌊🌊🌊🌊
 			wg.Add(1)
-			go pixelflut.Flut(img, offset, *shuffle, *address, *connections, stopChan, &wg)
+			go pixelflut.Flut(img, offset, *shuffle, false, false, false, *address, *connections, stopChan, &wg)
 		}
 
 	} else if *hevringAddr != "" {

pixelflut/api.go

@@ -6,21 +6,20 @@ import (
 	"image"
 	"image/color"
 	"log"
+	"math/rand"
 	"net"
 	"sync"
 
 	"github.com/SpeckiJ/Hochwasser/render"
 )
 
-var funmode = false
-
 // Flut asynchronously sends the given image to pixelflut server at `address`
 //   using `conns` connections. Pixels are sent column wise, unless `shuffle`
 //   is set. Stops when stop is closed.
 // @cleanup: use FlutTask{} as arg
-func Flut(img *image.NRGBA, position image.Point, shuffle bool, address string, conns int, stop chan bool, wg *sync.WaitGroup) {
+func Flut(img *image.NRGBA, position image.Point, shuffle, rgbsplit, randoffset, recreateConns bool, address string, conns int, stop chan bool, wg *sync.WaitGroup) {
 	var cmds commands
-	if funmode {
+	if rgbsplit {
 		// do a RGB split of white
 		imgmod := render.ImgColorFilter(img, color.NRGBA{0xff, 0xff, 0xff, 0xff}, color.NRGBA{0xff, 0, 0, 0xff})
 		cmds = append(cmds, commandsFromImage(imgmod, image.Pt(position.X-10, position.Y-10))...)
@@ -36,11 +35,31 @@ func Flut(img *image.NRGBA, position image.Point, shuffle bool, address string,
 	if shuffle {
 		cmds.Shuffle()
 	}
-	messages := cmds.Chunk(conns)
+
+	var messages [][]byte
+	var maxX, maxY int
+	if randoffset {
+		maxX, maxY = CanvasSize(address)
+		messages = cmds.Chunk(1) // each connection should send the full img
+	} else {
+		messages = cmds.Chunk(conns)
+	}
 
 	bombWg := sync.WaitGroup{}
-	for _, msg := range messages {
+	for i := 0; i < conns; i++ {
+		msg := messages[0]
+		if len(messages) > i {
+			msg = messages[i]
+		}
+
 		bombWg.Add(1)
+		if randoffset {
+			msg = append(OffsetCmd(
+				rand.Intn(maxX-img.Bounds().Canon().Dx()),
+				rand.Intn(maxY-img.Bounds().Canon().Dy()),
+			), msg...)
+		}
+
 		go bombAddress(msg, address, stop, &bombWg)
 	}
 	bombWg.Wait()
@@ -49,6 +68,23 @@ func Flut(img *image.NRGBA, position image.Point, shuffle bool, address string,
 	}
 }
 
+// CanvasSize returns the size of the canvas as returned by the server
+func CanvasSize(address string) (int, int) {
+	conn, err := net.Dial("tcp", address)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer conn.Close()
+
+	conn.Write([]byte("SIZE\n"))
+	reader := bufio.NewReader(conn)
+	res, err := reader.ReadSlice('\n')
+	if err != nil {
+		log.Fatal(err)
+	}
+	return parseXY(res[5:])
+}
+
 // FetchImage asynchronously uses `conns` to fetch pixels within `bounds` from
 //   a pixelflut server at `address`, and writes them into the returned Image.
 func FetchImage(bounds image.Rectangle, address string, conns int, stop chan bool) (img *image.NRGBA) {
@@ -84,15 +120,7 @@ func readPixels(target *image.NRGBA, conn net.Conn, stop chan bool) {
 
 			// parse response ("PX <x> <y> <col>\n")
 			colorStart := len(res) - 7
-			xy := res[3 : colorStart-1]
-			yStart := 0
-			for yStart = len(xy) - 2; yStart >= 0; yStart-- {
-				if xy[yStart] == ' ' {
-					break
-				}
-			}
-			x := asciiToInt(xy[:yStart])
-			y := asciiToInt(xy[yStart+1:])
+			x, y := parseXY(res[3 : colorStart-1])
 			hex.Decode(col, res[colorStart:len(res)-1])
 
 			target.SetNRGBA(x, y, color.NRGBA{col[0], col[1], col[2], 255})
@@ -100,6 +128,19 @@ func readPixels(target *image.NRGBA, conn net.Conn, stop chan bool) {
 	}
 }
 
+func parseXY(xy []byte) (int, int) {
+	last := len(xy) - 1
+	yStart := last - 1 // y is at least one char long
+	for ; yStart >= 0; yStart-- {
+		if xy[yStart] == ' ' {
+			break
+		}
+	}
+	x := asciiToInt(xy[:yStart])
+	y := asciiToInt(xy[yStart+1 : last])
+	return x, y
+}
+
 func asciiToInt(buf []byte) (v int) {
 	for _, c := range buf {
 		v = v*10 + int(c-'0')

pixelflut/commands.go

@@ -32,6 +32,11 @@ func (c commands) Shuffle() {
 	}
 }
 
+// AddOffset uses the OFFSET command to send the image at a specific place (not supported by all servers. example: https://github.com/TobleMiner/shoreline)
+func OffsetCmd(x, y int) []byte {
+	return []byte(fmt.Sprintf("OFFSET %d %d\n", x, y))
+}
+
 // CommandsFromImage converts an image to the respective pixelflut commands
 func commandsFromImage(img *image.NRGBA, offset image.Point) (cmds commands) {
 	b := img.Bounds()

rpc/dottir.go

@@ -30,12 +30,14 @@ type Hevring struct {
 }
 
 type FlutTask struct {
-	Address  string
-	MaxConns int
-	Img      *image.NRGBA
-	Offset   image.Point
-	Shuffle  bool
-	// Effects  []string // @idea shuffle, rgbsplit, randoffset, ...
+	Address    string
+	MaxConns   int
+	Img        *image.NRGBA
+	Offset     image.Point
+	Shuffle    bool // TODO: refactor these as RenderOpts bitfield
+	RGBSplit   bool
+	RandOffset bool
+	NewConn    bool
 }
 
 type FlutAck struct{ Ok bool }
@@ -56,7 +58,7 @@ func (h *Hevring) Flut(task FlutTask, reply *FlutAck) error {
 	h.task = task
 	h.taskQuit = make(chan bool)
 
-	go pixelflut.Flut(task.Img, task.Offset, task.Shuffle, task.Address, task.MaxConns, h.taskQuit, nil)
+	go pixelflut.Flut(task.Img, task.Offset, task.Shuffle, task.RGBSplit, task.RandOffset, task.NewConn, task.Address, task.MaxConns, h.taskQuit, nil)
 	reply.Ok = true
 	return nil
 }

rpc/repl.go

@@ -82,6 +82,21 @@ func RunREPL(f Fluter) {
 				t.Shuffle = !t.Shuffle
 				f.applyTask(t)
 
+			case "rgbsplit":
+				t := f.getTask()
+				t.RGBSplit = !t.RGBSplit
+				f.applyTask(t)
+
+			case "randoffset":
+				t := f.getTask()
+				t.RandOffset = !t.RandOffset
+				f.applyTask(t)
+
+			case "newconn":
+				t := f.getTask()
+				t.NewConn = !t.NewConn
+				f.applyTask(t)
+
 			case "txt":
 				if len(args) > 0 {
 					if size, err := strconv.Atoi(args[0]); err == nil {