From aa8c3128db15bdadf241fd36d275bb0109158cbf Mon Sep 17 00:00:00 2001
From: Edgaru089 <sjs333@outlook.com>
Date: Fri, 25 Feb 2022 21:33:51 +0800
Subject: [PATCH] tweak world generation

---
 internal/world/worldgen/worldgen.go | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/internal/world/worldgen/worldgen.go b/internal/world/worldgen/worldgen.go
index 48863b5..20780ec 100644
--- a/internal/world/worldgen/worldgen.go
+++ b/internal/world/worldgen/worldgen.go
@@ -27,6 +27,18 @@ func init() {
 	perlins = make(map[int64]*perlin.Perlin)
 }
 
+func fractal(p *perlin.Perlin, x, y float64, levels int) float64 {
+	ans := 0.0
+	amp := 1.0
+	for i := 0; i < levels; i++ {
+		ans += amp * p.Noise2D(x, y)
+		amp /= 3
+		x *= 2
+		y *= 2
+	}
+	return ans
+}
+
 // Chunk generates the chunk (must with chunkID set!!) with seed.
 func Chunk(chunk *packworld.Chunk, world *packworld.World, seed int64) {
 
@@ -50,9 +62,10 @@ func Chunk(chunk *packworld.Chunk, world *packworld.World, seed int64) {
 	for x := 0; x < packworld.ChunkSizeX; x++ {
 		for z := 0; z < packworld.ChunkSizeZ; z++ {
 
-			height := Lowest + int(float64(Highest-Lowest)*(p.Noise2D(
+			height := Lowest + int(float64(Highest-Lowest)*(fractal(
+				p,
 				float64(offX+x)/AltitudeDensity,
-				float64(offZ+z)/AltitudeDensity)/2+0.5))
+				float64(offZ+z)/AltitudeDensity, 6)/2+0.5))
 			//log.Printf("height = %d (noise=%.5f)", height, p.Noise2D(float64(offX+x)/AltitudeDensity, float64(offZ+z)/AltitudeDensity)/2+0.5)
 
 			// water