biome depth stuff

mc/gen/biome_noise.go

@@ -1,5 +1,7 @@
 package gen
 
+import "math"
+
 type NoiseParam int
 
 const (
@@ -54,6 +56,10 @@ func BiomeNoiseFromXoroshiro(x Xoroshiro, large bool) (v BiomeNoise) {
 	return
 }
 
+func peaksAndValleys(weirdness float64) float64 {
+	return -(math.Abs(math.Abs(weirdness)-0.6666667) - 0.33333334) * 3.0
+}
+
 func (b BiomeNoise) Sample(x, y, z int) (t, h, c, e, d, w float64, combinedData [6]int64, id int) {
 	px := float64(x)
 	pz := float64(z)
@@ -66,6 +72,9 @@ func (b BiomeNoise) Sample(x, y, z int) (t, h, c, e, d, w float64, combinedData
 	t = b.Temperature.Sample(px, 0, pz)
 	h = b.Humidity.Sample(px, 0, pz)
 
+	off := float64(BiomeDepthSpline.Sample([]float32{float32(c), float32(e), float32(peaksAndValleys(w)), float32(w)})) + 0.015
+	d = 1.0 - (float64(y)*4)/128.0 - 83.0/160.0 + off
+
 	combinedData = [6]int64{
 		int64(float32(t) * 10000.0),
 		int64(float32(h) * 10000.0),

mc/gen/xoroshiro_test.go

@@ -38,7 +38,7 @@ func TestBiome(t *testing.T) {
 	b := BiomeNoiseFromXoroshiro(x, false)
 	_, _, _, _, _, _, combinedData, _ := b.Sample(-1, -16, 0)
 
-	expected := [6]int64{3238, 3521, 2364, 1396, 0, 2202}
+	expected := [6]int64{3238, 3521, 2364, 1396, 10062, 2202}
 	if combinedData != expected {
 		t.Errorf("combinedData = %v, want %v", combinedData, expected)
 	}