130 lines
2.9 KiB
Go
130 lines
2.9 KiB
Go
package pixelflut
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import (
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"fmt"
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"image"
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"image/color"
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"math/rand"
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"strconv"
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)
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// Commands represent a list of messages to be sent to a pixelflut server.
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type commands [][]byte
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// Chunk splits commands into equally sized chunks, while flattening each chunk
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// so that all commands are concatenated as a single `[]byte`.
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func (c commands) Chunk(numChunks int) [][]byte {
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chunks := make([][]byte, numChunks)
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chunkLength := len(c) / numChunks
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for i := 0; i < numChunks; i++ {
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cmdOffset := i * chunkLength
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for j := 0; j < chunkLength; j++ {
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chunks[i] = append(chunks[i], c[cmdOffset+j]...)
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}
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}
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return chunks
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}
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// Shuffle reorders commands randomly, in place.
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func (c commands) Shuffle() {
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for i := range c {
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j := rand.Intn(i + 1)
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c[i], c[j] = c[j], c[i]
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}
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}
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// OffsetCmd applies offset to all following requests. Not supported by all servers. example: https://github.com/TobleMiner/shoreline.
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func OffsetCmd(x, y int) []byte {
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return []byte(fmt.Sprintf("OFFSET %d %d\n", x, y))
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}
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// CommandsFromImage converts an image to the respective pixelflut commands
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func commandsFromImage(img *image.NRGBA, order RenderOrder, offset image.Point) (cmds commands) {
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b := img.Bounds()
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cmds = make([][]byte, b.Size().X*b.Size().Y)
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numCmds := 0
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max1 := b.Max.X
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max2 := b.Max.Y
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min1 := b.Min.X
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min2 := b.Min.Y
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dir := 1
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if order.IsVertical() {
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max1, max2 = max2, max1
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min1, min2 = min2, min1
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}
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if order.IsReverse() {
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min1, max1 = max1, min1
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min2, max2 = max2, min2
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dir *= -1
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}
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for i1 := min1; i1 != max1; i1 += dir {
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for i2 := min2; i2 != max2; i2 += dir {
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x := i1
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y := i2
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if order.IsVertical() {
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x, y = y, x
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}
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c := img.NRGBAAt(x, y)
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if c.A == 0 {
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continue
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}
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var cmd []byte
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cmd = append(cmd, []byte("PX ")...)
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cmd = strconv.AppendUint(cmd, uint64(x+offset.X), 10)
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cmd = append(cmd, ' ')
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cmd = strconv.AppendUint(cmd, uint64(y+offset.Y), 10)
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cmd = append(cmd, ' ')
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appendColor(&cmd, c)
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cmd = append(cmd, '\n')
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cmds[numCmds] = cmd
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numCmds++
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}
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}
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cmds = cmds[:numCmds]
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if order == Shuffle {
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cmds.Shuffle()
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}
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return
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}
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func appendColor(buf *[]byte, c color.NRGBA) {
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var mask uint32 = 0xf0000000
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// merge into uint32
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var col = uint32(c.R)<<24 + uint32(c.G)<<16 + uint32(c.B)<<8 + uint32(c.A)
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// if alpha is ff, drop it.
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if 0xff&col == 0xff {
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col = col >> 8
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mask = mask >> 8
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}
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// add leading zeros if needed
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for mask > 0xf {
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if mask&col == 0 {
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*buf = append(*buf, '0')
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} else {
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break
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}
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mask = mask >> 4
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}
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*buf = strconv.AppendUint(*buf, uint64(col), 16)
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}
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func cmdsFetchImage(bounds image.Rectangle) (cmds commands) {
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cmds = make([][]byte, bounds.Size().X*bounds.Size().Y)
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numCmds := 0
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for x := bounds.Min.X; x < bounds.Max.X; x++ {
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for y := bounds.Min.Y; y < bounds.Max.Y; y++ {
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cmd := fmt.Sprintf("PX %d %d\n", x, y)
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cmds[numCmds] = []byte(cmd)
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numCmds++
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}
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}
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return cmds
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}
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