func (g *generator) buildTerrain(mpath minecraft.Path, level *level, terrain, biomes, plants *image.Paletted, height, water *image.Gray, c chan paint) error {
b := terrain.Bounds()
proceed := make(chan uint8, 10)
errChan := make(chan error, 1)
go func() {
defer close(proceed)
cc := newCache(g.Terrain.Blocks)
for j := 0; j < b.Max.Y; j += 16 {
chunkZ := int32(j >> 4)
for i := 0; i < b.Max.X; i += 16 {
chunkX := int32(i >> 4)
h := int32(meanHeight(height.SubImage(image.Rect(i, j, i+16, j+16)).(*image.Gray)))
wh := int32(meanHeight(water.SubImage(image.Rect(i, j, i+16, j+16)).(*image.Gray)))
var t uint8
if wh >= h<<1 { // more water than land...
c <- paint{
color.RGBA{0, 0, 255, 255},
chunkX, chunkZ,
}
t = uint8(len(g.Terrain.Blocks) - 1)
h = wh
} else {
t = modeTerrain(terrain.SubImage(image.Rect(i, j, i+16, j+16)).(*image.Paletted), len(g.Terrain.Palette))
c <- paint{
g.Terrain.Palette[t],
chunkX, chunkZ,
}
}
if err := mpath.SetChunk(cc.getFromCache(chunkX, chunkZ, t, h)); err != nil {
errChan <- err
return
}
proceed <- t
}
}
}()
ts := make([]uint8, 0, 1024)
for i := 0; i < (b.Max.X>>4)+2; i++ {
ts = append(ts, <-proceed) // get far enough ahead so all chunks are surrounded before shaping, to get correct lighting
}
select {
case err := <-errChan:
return err
default:
}
for j := int32(0); j < int32(b.Max.Y); j += 16 {
chunkZ := j >> 4
for i := int32(0); i < int32(b.Max.X); i += 16 {
chunkX := i >> 4
var totalHeight int32
ot := ts[0]
ts = ts[1:]
oy, _ := level.GetHeight(i, j)
for x := i; x < i+16; x++ {
for z := j; z < j+16; z++ {
if biomes != nil {
level.SetBiome(x, z, g.Biomes.Values[biomes.ColorIndexAt(int(x), int(z))])
}
h := int32(height.GrayAt(int(x), int(z)).Y)
totalHeight += h
wl := int32(water.GrayAt(int(x), int(z)).Y)
y := oy
if h > y {
y = h
}
if wl > y {
y = wl
}
for ; y > h && y > wl; y-- {
level.SetBlock(x, y, z, minecraft.Block{})
}
if plants != nil {
p := g.Plants.Blocks[plants.ColorIndexAt(int(x), int(z))]
py := int32(1)
for ; py <= int32(p.Level); py++ {
level.SetBlock(x, y+py, z, p.Base)
}
level.SetBlock(x, y+py, z, p.Top)
}
for ; y > h; y-- {
level.SetBlock(x, y, z, minecraft.Block{ID: 9})
}
t := terrain.ColorIndexAt(int(x), int(z))
tb := g.Terrain.Blocks[t]
for ; y > h-int32(tb.Level); y-- {
level.SetBlock(x, y, z, tb.Top)
}
if t != ot {
h = 0
} else {
h = oy
}
for ; y >= h; y-- {
level.SetBlock(x, y, z, tb.Base)
}
}
}
c <- paint{
color.Alpha{uint8(totalHeight >> 8)},
chunkX, chunkZ,
}
select {
case p, ok := <-proceed:
if ok {
ts = append(ts, p)
}
case err := <-errChan:
return err
}
}
}
return nil
}