bedrocktool/map_item.go

package main

import (
	"bytes"
	"image"
	"image/draw"
	"math"
	"os"
	"sync"

	"github.com/df-mc/dragonfly/server/world/chunk"
	"github.com/sandertv/gophertunnel/minecraft/protocol"
	"github.com/sandertv/gophertunnel/minecraft/protocol/packet"
	"golang.org/x/image/bmp"
)

const VIEW_MAP_ID = 0x424242

// packet to tell the client that it has a map with id 0x424242 in the offhand
var MAP_ITEM_PACKET packet.InventoryContent = packet.InventoryContent{
	WindowID: 119,
	Content: []protocol.ItemInstance{
		{
			StackNetworkID: 1,
			Stack: protocol.ItemStack{
				ItemType: protocol.ItemType{
					NetworkID:     420,
					MetadataValue: 0,
				},
				BlockRuntimeID: 0,
				Count:          1,
				NBTData: map[string]interface{}{
					"map_uuid": int64(VIEW_MAP_ID),
				},
			},
		},
	},
}

type MapUI struct {
	img           *image.RGBA                       // rendered image
	minZoom       bool                              // 1 pixel per block
	chunks_images map[protocol.ChunkPos]*image.RGBA // prerendered chunks
	needRedraw    bool                              // when the map has updated this is true
	send_lock     *sync.Mutex
}

func NewMapUI() MapUI {
	return MapUI{
		img:           image.NewRGBA(image.Rect(0, 0, 128, 128)),
		minZoom:       true,
		chunks_images: make(map[protocol.ChunkPos]*image.RGBA),
		needRedraw:    true,
		send_lock:     &sync.Mutex{},
	}
}

// Reset resets the map to inital state
func (m *MapUI) Reset() {
	m.chunks_images = make(map[protocol.ChunkPos]*image.RGBA)
	m.needRedraw = true
}

// ChangeZoom adds to the zoom value and goes around to 32 once it hits 128
func (m *MapUI) ChangeZoom() {
	m.minZoom = !m.minZoom
	m.SchedRedraw()
}

// SchedRedraw tells the map to redraw the next time its sent
func (m *MapUI) SchedRedraw() {
	m.needRedraw = true
}

// draw_img_scaled_pos draws src onto dst at bottom_left, scaled to size
func draw_img_scaled_pos(dst *image.RGBA, src *image.RGBA, bottom_left image.Point, size_scaled int) {
	sbx := src.Bounds().Dx()
	sby := src.Bounds().Dy()

	ratio := float64(sbx) / float64(size_scaled)

	for x_in := 0; x_in < sbx; x_in++ {
		for y_in := 0; y_in < sby; y_in++ {
			c := src.At(x_in, y_in)
			x_out := int(float64(bottom_left.X) + float64(x_in)/ratio)
			y_out := int(float64(bottom_left.Y) + float64(y_in)/ratio)
			dst.Set(x_out, y_out, c)
		}
	}
}

// draw chunk images to the map image
func (m *MapUI) Redraw(w *WorldState) {
	// get the chunk coord bounds
	min := protocol.ChunkPos{}
	max := protocol.ChunkPos{}
	for _ch := range m.chunks_images {
		if _ch.X() < min.X() {
			min[0] = _ch.X()
		}
		if _ch.Z() < min.Z() {
			min[1] = _ch.Z()
		}
		if _ch.X() > max.X() {
			max[0] = _ch.X()
		}
		if _ch.Z() > max.Z() {
			max[1] = _ch.Z()
		}
	}

	middle := protocol.ChunkPos{
		int32(w.PlayerPos.Position.X()),
		int32(w.PlayerPos.Position.Z()),
	}

	chunks_x := int(max[0] - min[0] + 1) // how many chunk lengths is x coordinate
	chunks_y := int(max[1] - min[1] + 1)
	chunks_per_line := 16 * math.Ceil(math.Min(float64(chunks_x), 32)/16)
	if m.minZoom {
		chunks_per_line = 8
	}
	px_per_block := float64(128 / chunks_per_line / 16) // how many pixels per block
	sz_chunk := int(math.Ceil(px_per_block * 16))

	for i := 0; i < len(m.img.Pix); i++ { // clear canvas
		m.img.Pix[i] = 0
	}

	for _ch := range m.chunks_images {
		relative_middle_x := float64(_ch.X()*16 - middle.X())
		relative_middle_z := float64(_ch.Z()*16 - middle.Z())
		px_pos := image.Point{ // bottom left corner of the chunk on the map
			X: int(math.Floor(relative_middle_x*px_per_block)) + 64,
			Y: int(math.Floor(relative_middle_z*px_per_block)) + 64,
		}

		if !m.img.Rect.Intersect(image.Rect(px_pos.X, px_pos.Y, px_pos.X+sz_chunk, px_pos.Y+sz_chunk)).Empty() {
			draw_img_scaled_pos(m.img, m.chunks_images[_ch], image.Point{
				px_pos.X, px_pos.Y,
			}, sz_chunk)
		}
	}

	draw_full := false

	if draw_full {
		img2 := image.NewRGBA(image.Rect(0, 0, chunks_x*16, chunks_y*16))

		middle_block_x := chunks_x / 2 * 16
		middle_block_y := chunks_y / 2 * 16

		for _ch := range m.chunks_images {
			px_pos := image.Point{
				X: int(_ch.X()*16) - middle_block_x + img2.Rect.Dx(),
				Y: int(_ch.Z()*16) - middle_block_y + img2.Rect.Dy(),
			}
			draw.Draw(img2, image.Rect(
				px_pos.X,
				px_pos.Y,
				px_pos.X+16,
				px_pos.Y+16,
			), m.chunks_images[_ch], image.Point{}, draw.Src)
		}
		buf := bytes.NewBuffer(nil)
		bmp.Encode(buf, img2)
		os.WriteFile("test.bmp", buf.Bytes(), 0o777)
	}
}

// send
func (m *MapUI) Send(w *WorldState) error {
	if !m.send_lock.TryLock() {
		return nil // dont send if send is in progress
	}

	// redraw if needed
	if m.needRedraw {
		m.needRedraw = false
		m.Redraw(w)
	}

	m.send_lock.Unlock()
	if w.proxy.client != nil {
		return w.proxy.client.WritePacket(&packet.ClientBoundMapItemData{
			MapID:       VIEW_MAP_ID,
			Width:       128,
			Height:      128,
			Pixels:      img2rgba(m.img),
			UpdateFlags: 2,
		})
	}
	return nil
}

func (m *MapUI) SetChunk(pos protocol.ChunkPos, ch *chunk.Chunk) {
	var img *image.RGBA
	if ch != nil {
		img = Chunk2Img(ch)
	} else {
		img = black_16x16
	}
	m.send_lock.Lock() // dont send while adding a chunk
	m.chunks_images[pos] = img
	m.send_lock.Unlock()
	m.SchedRedraw()
}