// For a chunk at a coordinate, create it.
// There is no need for a lock, as no one can access the chunk
// TODO: Some algorithms depend on looking at the block above, which can only be done when inside the
// chunk. If the test would require looking at another chunk, the tets skipped. This leads to some special
// effects failure.
func dBCreateChunk(c chunkdb.CC) *chunk {
start := time.Now()
ch := new(chunk)
ch.rc = new(raw_chunk)
ch.coord = c
z1 := int(c.Z * CHUNK_SIZE)
for x := int32(0); x < CHUNK_SIZE; x++ {
xf := float64(x + c.X*CHUNK_SIZE)
for y := int32(0); y < CHUNK_SIZE; y++ {
yf := float64(y + c.Y*CHUNK_SIZE)
highFreq := 20 * simplexnoise.Noise2(xf*0.016, yf*0.016) // This will generate high frequency terrain
f := simplexnoise.Noise2(xf*0.0025, yf*0.0025) // Factor to modulate the high frequency amplitude
lowFreq := 15 * simplexnoise.Noise2(xf*0.0013, yf*0.0013) // Low frequency terrain
stoneheight := math.Floor(2.5 + highFreq*f*f + lowFreq)
// Given 'height', fill in the content of the current chunk. Iterate from high 'z' to low,
// to enable tests that depends on the block above.
for z := CHUNK_SIZE - 1; z >= 0; z-- {
if *inhibitCreateChunks {
ch.rc[x][y][z] = BT_Air
continue
}
zf := float64(z + z1)
if zf > FLOATING_ISLANDS_LIM {
// Use a gradial transient, or all islands would have a hard cut off.
f := (1-FLOATING_ISLANDS_PROB)/CHUNK_SIZE*(zf-FLOATING_ISLANDS_LIM) + FLOATING_ISLANDS_PROB
if f > 1 {
f = 1
}
density := f * dBdensity(xf/2, yf/2, zf) // Use a compressed layout in height
if density > FLOATING_ISLANDS_PROB {
if z != CHUNK_SIZE-1 && blockIsInvisible[ch.rc[x][y][z+1]] {
ch.rc[x][y][z] = BT_Soil // Put grass on top
} else {
ch.rc[x][y][z] = BT_Stone
}
} else {
ch.rc[x][y][z] = BT_Air
}
continue
}
density := dBdensity(xf/2, yf/2, zf)
soildepth := math.Floor(2*simplexnoise.Noise2(xf*0.012, yf*0.012) + 2.8)
if stoneheight > WORLD_SOIL_LEVEL {
soildepth = 0
} else if soildepth+stoneheight > WORLD_SOIL_LEVEL {
soildepth = WORLD_SOIL_LEVEL - stoneheight
}
height := stoneheight + soildepth
ch.rc[x][y][z] = BT_Air
if zf <= stoneheight {
// Initialize with stone, may be updated below
if zf > 24 {
ch.rc[x][y][z] = BT_Snow
} else {
ch.rc[x][y][z] = BT_Stone
}
} else if zf <= stoneheight+soildepth {
// Initialize with soil, may be updated below
ch.rc[x][y][z] = BT_Soil
}
// Excavate some holes in the terrain. Don't let the hole go too deep
const HOLEDEPTH = 50 // Max depth of hole
if zf > -HOLEDEPTH && zf < HOLEDEPTH {
density := dBdensity(xf, yf, zf) // This costs a lot of CPU
fadeoff := 1.0
if zf >= -HOLEDEPTH && zf <= 0 {
fadeoff = (HOLEDEPTH + zf) / HOLEDEPTH
} else if zf < -HOLEDEPTH {
fadeoff = 0
}
if density*fadeoff > 0.7 {
ch.rc[x][y][z] = BT_Air
}
}
// Some special cases if below water line
if zf <= 0 {
if ch.rc[x][y][z] == BT_Air {
ch.rc[x][y][z] = BT_Water
} else if ch.rc[x][y][z] == BT_Soil {
ch.rc[x][y][z] = BT_Stone
}
if ch.rc[x][y][z] == BT_Stone && z+z1 == 0 && blockIsInvisible[ch.rc[x][y][1]] {
// Replace stone with sand if it is at water level and air above.
ch.rc[x][y][0] = BT_Sand
}
}
a := density > 0.5-CnfgCaveWidth/2 && density < 0.5+CnfgCaveWidth/2
if zf <= height && a {
density2 := dBdensity(1000-xf/2, 1000-yf/2, 1000-zf) // Use a compressed layout in height
b := density2 > 0.5-CnfgCaveWidth/2 && density2 < 0.5+CnfgCaveWidth/2
if b && ch.rc[x][y][z] != BT_Water {
ch.rc[x][y][z] = BT_Air
}
}
// Add some scenery
if ch.rc[x][y][z] == BT_Soil && z+1 < CHUNK_SIZE && blockIsInvisible[ch.rc[x][y][z+1]] {
// This is a candidate for a tree override
const (
t3 = 0.0005 // Very few big trees
t2 = 0.005
t1 = 0.010
tflower = 0.012 // Less flowers than tuft of grass
ttuft = 0.020
)
rnd := math.Abs(simplexnoise.Noise2(xf*422.34, yf*234.123)) // Without scaling, there is a line where xf+yf==0 gives rnd=0
if rnd > t1 {
continue // Not needed for the algorithm but will save a call to Noise2.
}
// Use a low frequency function to make less trees for some areas.
lowFreq := 1 - math.Abs(simplexnoise.Noise2(xf*0.002, yf*0.002))
// The lowFreq function takes away too many trees, ease it up a little
lowFreq = 1 - lowFreq*lowFreq
// fmt.Printf("%.5f ", lowFreq)
switch {
case rnd < t3*lowFreq:
ch.rc[x][y][z+1] = BT_Tree3
case rnd < t2*lowFreq:
ch.rc[x][y][z+1] = BT_Tree2
case rnd < t1*lowFreq:
ch.rc[x][y][z+1] = BT_Tree1
case rnd < tflower*lowFreq:
ch.rc[x][y][z+1] = BT_Flowers
case rnd < ttuft*lowFreq:
ch.rc[x][y][z+1] = BT_Tuft
}
}
}
}
}
ch.compress()
ch.updateChecksum()
ch.touched = true
delta := time.Now().Sub(start)
DBCreateStats.Num++
DBCreateStats.TotTime += delta
return ch
}
func DoTestSimplexNoise() {
var min, max float64
min, max = 1, -1
const iter = 1e7
var sum float64
for i := 0; i < iter; i++ {
switch rnd := simplexnoise.Noise1(float64(i) * 1.827231321); {
case rnd < min:
min = rnd
sum += rnd
case rnd > max:
max = rnd
sum += rnd
default:
sum += rnd
}
}
// fmt.Printf("DoTestSimplexNoise simplexnoise.Noise1 min %v, max %v, average %v\n", min, max, sum/iter)
DoTestCheck("DoTestSimplexNoise simplexnoise.Noise1 min=-1.0", math.Abs(min+1) < 1e-3)
DoTestCheck("DoTestSimplexNoise simplexnoise.Noise1 max=1.0", math.Abs(max-1) < 1e-3)
DoTestCheck("DoTestSimplexNoise simplexnoise.Noise1 average=0.0", math.Abs(sum/iter) < 0.04) // Not very good, off by more than 3%
min, max = 1, -1
sum = 0
for i := 0; i < iter; i++ {
switch rnd := simplexnoise.Noise2(float64(i)*1.827411321, float64(i)*7.12312781); {
case rnd < min:
min = rnd
sum += rnd
case rnd > max:
max = rnd
sum += rnd
default:
sum += rnd
}
}
// fmt.Printf("DoTestSimplexNoise simplexnoise.Noise2 min %v, max %v, average %v\n", min, max, sum/iter)
DoTestCheck("DoTestSimplexNoise simplexnoise.Noise2 min=-1.0", math.Abs(min+1) < 1e-3)
DoTestCheck("DoTestSimplexNoise simplexnoise.Noise2 max=1.0", math.Abs(max-1) < 1e-3)
DoTestCheck("DoTestSimplexNoise simplexnoise.Noise2 average=0.0", math.Abs(sum/iter) < 1e-4)
min, max = 1, -1
sum = 0
for i := 0; i < iter; i++ {
switch rnd := simplexnoise.Noise3(float64(i)*1.827131321, float64(i)*7.12372381, float64(i)*4.923716223); {
case rnd < min:
min = rnd
sum += rnd
case rnd > max:
max = rnd
sum += rnd
default:
sum += rnd
}
}
// fmt.Printf("DoTestSimplexNoise simplexnoise.Noise3 min %v, max %v, average %v\n", min, max, sum/iter)
DoTestCheck("DoTestSimplexNoise simplexnoise.Noise3 min=-1.0", math.Abs(min+1) < 1e-3)
DoTestCheck("DoTestSimplexNoise simplexnoise.Noise3 max=1.0", math.Abs(max-1) < 1e-3)
DoTestCheck("DoTestSimplexNoise simplexnoise.Noise3 average=0.0", math.Abs(sum/iter) < 1e-4)
}