mtwebmapper: Move BaseTileCreator to common. TODO: Make mtseeder use it, too.

common/basetilecreator.go

@@ -0,0 +1,145 @@
+// Copyright 2014 by Sascha L. Teichmann
+// Use of this source code is governed by the MIT license
+// that can be found in the LICENSE file.
+
+package common
+
+import (
+	"fmt"
+	"image/color"
+	"log"
+	"os"
+	"path/filepath"
+	"strconv"
+)
+
+const (
+	tileWidth      = 18
+	tileHeight     = 18
+	yOrderCapacity = 512
+)
+
+// To scan the whole height in terms of the y coordinate
+// the database is queried in height units defined in the tileDepths table.
+var tileDepths = [...][2]int16{
+	{1024, 1934},
+	{256, 1023},
+	{128, 255},
+	{64, 127},
+	{32, 63},
+	{16, 31},
+	{8, 15},
+	{4, 7},
+	{2, 3},
+	{0, 1},
+	{-1, 0},
+	{-4, -2},
+	{-8, -5},
+	{-16, -9},
+	{-32, -17},
+	{-64, -33},
+	{-128, -65},
+	{-256, -129},
+	{-1024, -257},
+	{-1934, -1025}}
+
+type BaseTileCreator struct {
+	client   *RedisClient
+	colors   *Colors
+	renderer *Renderer
+	yOrder   *YOrder
+	baseDir  string
+	update   bool
+}
+
+func NewBaseTileCreator(
+	client *RedisClient,
+	colors *Colors,
+	baseDir string,
+	update bool) *BaseTileCreator {
+	renderer := NewRenderer(tileWidth, tileHeight)
+	return &BaseTileCreator{
+		client:   client,
+		colors:   colors,
+		renderer: renderer,
+		yOrder:   NewYOrder(renderer, yOrderCapacity),
+		baseDir:  baseDir,
+		update:   update}
+}
+
+func (btc *BaseTileCreator) Close() error {
+	return btc.client.Close()
+}
+
+func (btc *BaseTileCreator) CreateTile(x, z int16, i, j int) error {
+	btc.renderer.Reset()
+	btc.renderer.SetPos(x, z)
+	btc.yOrder.Reset()
+
+	drawBlock := func(block *Block) {
+		if err := btc.yOrder.RenderBlock(block, btc.colors.NameIndex); err != nil {
+			log.Printf("WARN: rendering block failed: %s", err)
+		}
+	}
+
+	var c1, c2 Coord
+
+	nareas := make([]Area, 0, tileWidth*tileHeight/2)
+	oareas := make([]Area, 1, tileWidth*tileHeight/2)
+
+	oareas[0] = Area{
+		X1: 0, Z1: 0,
+		X2: int16(tileWidth) - 1, Z2: int16(tileHeight) - 1}
+
+	for _, yRange := range tileDepths {
+		c1.Y = yRange[0]
+		c2.Y = yRange[1]
+
+		nareas = btc.renderer.UncoveredAreas(nareas, oareas)
+
+		if len(nareas) == 0 {
+			break
+		}
+
+		for _, area := range nareas {
+			c1.X = area.X1 + x
+			c1.Z = area.Z1 + z
+			c2.X = area.X2 + x
+			c2.Z = area.Z2 + z
+			query := Cuboid{P1: c1, P2: c2}
+			if err := btc.client.QueryCuboid(query, drawBlock); err != nil {
+				return err
+			}
+			if err := btc.yOrder.Drain(btc.colors.NameIndex); err != nil {
+				log.Printf("WARN: rendering block failed: %s", err)
+			}
+		}
+		oareas, nareas = nareas, oareas[0:0]
+	}
+
+	image := btc.renderer.CreateShadedImage(
+		16, 16, (tileWidth-2)*16, (tileHeight-2)*16,
+		btc.colors.Colors, color.RGBA{R: 0xff, G: 0xff, B: 0xff, A: 0xff})
+
+	path := filepath.Join(btc.baseDir, strconv.Itoa(i), fmt.Sprintf("%d.png", j))
+
+	log.Printf("Writing (%d, %d) to file %s", x, z, path)
+
+	if !btc.update {
+		return SaveAsPNG(path, image)
+	}
+
+	// Try to make creation of update "atomic" by first writing to tmp file
+	// and rename the tmp file to the original one afterwards.
+	pathTmp := path + "tmp"
+	pathTmpPre := pathTmp
+	tc := 0
+	for _, err := os.Stat(pathTmp); err == nil; _, err = os.Stat(pathTmp) {
+		pathTmp = fmt.Sprintf("%s%d", pathTmpPre, tc)
+		tc++
+	}
+	if err := SaveAsPNG(pathTmp, image); err != nil {
+		return err
+	}
+	return os.Rename(pathTmp, path)
+}