From c99155fb47f784b8aab54e3da65e0c1cf2a86a85 Mon Sep 17 00:00:00 2001
From: a dinosaur <dino@a-dinosaur.com>
Date: Fri, 30 Aug 2024 21:56:39 +1000
Subject: [PATCH] split worldgen

---
 Sources/Voxelotl/CMakeLists.txt       |  1 +
 Sources/Voxelotl/Game.swift           | 16 +++--------
 Sources/Voxelotl/World.swift          | 39 +++++++-------------------
 Sources/Voxelotl/WorldGenerator.swift | 40 +++++++++++++++++++++++++++
 4 files changed, 55 insertions(+), 41 deletions(-)
 create mode 100644 Sources/Voxelotl/WorldGenerator.swift

diff --git a/Sources/Voxelotl/CMakeLists.txt b/Sources/Voxelotl/CMakeLists.txt
index 5b00820..2628f77 100644
--- a/Sources/Voxelotl/CMakeLists.txt
+++ b/Sources/Voxelotl/CMakeLists.txt
@@ -51,6 +51,7 @@ add_executable(Voxelotl MACOSX_BUNDLE
 
   # Game logic classes
   Chunk.swift
+  WorldGenerator.swift
   World.swift
   Raycast.swift
   Player.swift
diff --git a/Sources/Voxelotl/Game.swift b/Sources/Voxelotl/Game.swift
index 7bf0bbc..8671526 100644
--- a/Sources/Voxelotl/Game.swift
+++ b/Sources/Voxelotl/Game.swift
@@ -40,20 +40,12 @@ class Game: GameDelegate {
   }
 
   private func generateWorld() {
-    var random: any RandomProvider
-#if true
-    let newSeed = UInt64(Arc4Random.instance.next()) | UInt64(Arc4Random.instance.next()) << 32
-    printErr(newSeed)
-    random = Xoroshiro128PlusPlus(seed: newSeed)
-#else
-    random = PCG32Random(state: (
-      UInt64(Arc4Random.instance.next()) | UInt64(Arc4Random.instance.next()) << 32,
-      UInt64(Arc4Random.instance.next()) | UInt64(Arc4Random.instance.next()) << 32))
-#endif
+    let seed = UInt64(Arc4Random.instance.next()) | UInt64(Arc4Random.instance.next()) << 32
+    printErr(seed)
 #if DEBUG
-    self.world.generate(width: 2, height: 1, depth: 1, random: &random)
+    self.world.generate(width: 2, height: 1, depth: 1, seed: seed)
 #else
-    self.world.generate(width: 5, height: 3, depth: 5, random: &random)
+    self.world.generate(width: 5, height: 3, depth: 5, seed: seed)
 #endif
   }
 
diff --git a/Sources/Voxelotl/World.swift b/Sources/Voxelotl/World.swift
index 63e0d79..7bff672 100644
--- a/Sources/Voxelotl/World.swift
+++ b/Sources/Voxelotl/World.swift
@@ -2,11 +2,11 @@ import Foundation
 
 public class World {
   private var _chunks: Dictionary<SIMD3<Int>, Chunk>
-  private var noise: ImprovedPerlin<Float>!
-  private var noise2: SimplexNoise<Float>!
+  private var _generator: WorldGenerator
 
   public init() {
     self._chunks = [:]
+    self._generator = WorldGenerator()
   }
 
   func getBlock(at position: SIMD3<Int>) -> Block {
@@ -19,40 +19,21 @@ public class World {
     self._chunks[position &>> Chunk.shift]?.setBlock(at: position, type: type)
   }
 
-  func generate(width: Int, height: Int, depth: Int, random: inout any RandomProvider) {
-    self.noise = ImprovedPerlin<Float>(random: &random)
-    self.noise2 = SimplexNoise<Float>(random: &random)
-
-    for x in 0..<width {
+  func generate(width: Int, height: Int, depth: Int, seed: UInt64) {
+    self._generator.reset(seed: seed)
+    let orig = SIMD3(width, height, depth) / 2
+    for z in 0..<depth {
       for y in 0..<height {
-        for z in 0..<depth {
-          let chunkID = SIMD3(x, y, z) &- SIMD3(width, height, depth) / 2
-          self.generate(chunkID: chunkID)
+        for x in 0..<width {
+          let chunkID = SIMD3(x, y, z) &- orig
+          self._chunks[chunkID] = self._generator.makeChunk(id: chunkID)
         }
       }
     }
   }
 
   func generate(chunkID: SIMD3<Int>) {
-    let chunkOrigin = chunkID &<< Chunk.shift
-    var chunk = Chunk(position: chunkOrigin)
-    chunk.fill(allBy: { position in
-      let fpos = SIMD3<Float>(position)
-        let threshold: Float = 0.6
-        let value = fpos.y / Float(Chunk.size)
-          + self.noise.get(fpos * 0.05) * 1.1
-          + self.noise.get(fpos * 0.10) * 0.5
-          + self.noise.get(fpos * 0.30) * 0.23
-      return if value < threshold {
-        .solid(.init(
-          hue:        Float16(180 + self.noise2.get(fpos * 0.05) * 180),
-          saturation: Float16(0.5 + self.noise2.get(SIMD4(fpos * 0.05, 4)) * 0.5),
-          value:      Float16(0.5 + self.noise2.get(SIMD4(fpos * 0.05, 9)) * 0.5).lerp(0.5, 1)).linear)
-      } else {
-        .air
-      }
-    })
-    self._chunks[chunkID] = chunk
+    self._chunks[chunkID] = self._generator.makeChunk(id: chunkID)
   }
 
   var instances: [Instance] {
diff --git a/Sources/Voxelotl/WorldGenerator.swift b/Sources/Voxelotl/WorldGenerator.swift
new file mode 100644
index 0000000..2fe5142
--- /dev/null
+++ b/Sources/Voxelotl/WorldGenerator.swift
@@ -0,0 +1,40 @@
+struct WorldGenerator {
+  var noise: ImprovedPerlin<Float>!, noise2: SimplexNoise<Float>!
+
+  public mutating func reset(seed: UInt64) {
+    var random: any RandomProvider
+#if true
+    random = Xoroshiro128PlusPlus(seed: seed)
+#else
+    //TODO: Fill seed with a hash
+    random = PCG32Random(state: (
+      UInt64(Arc4Random.instance.next()) | UInt64(Arc4Random.instance.next()) << 32,
+      UInt64(Arc4Random.instance.next()) | UInt64(Arc4Random.instance.next()) << 32))
+#endif
+
+    self.noise = ImprovedPerlin<Float>(random: &random)
+    self.noise2 = SimplexNoise<Float>(random: &random)
+  }
+
+  public func makeChunk(id chunkID: SIMD3<Int>) -> Chunk {
+    let chunkOrigin = chunkID &<< Chunk.shift
+    var chunk = Chunk(position: chunkOrigin)
+    chunk.fill(allBy: { position in
+      let fpos = SIMD3<Float>(position)
+        let threshold: Float = 0.6
+        let value = fpos.y / Float(Chunk.size)
+          + self.noise.get(fpos * 0.05) * 1.1
+          + self.noise.get(fpos * 0.10) * 0.5
+          + self.noise.get(fpos * 0.30) * 0.23
+      return if value < threshold {
+        .solid(.init(
+          hue:        Float16(180 + self.noise2.get(fpos * 0.05) * 180),
+          saturation: Float16(0.5 + self.noise2.get(SIMD4(fpos * 0.05, 4)) * 0.5),
+          value:      Float16(0.5 + self.noise2.get(SIMD4(fpos * 0.05, 9)) * 0.5).lerp(0.5, 1)).linear)
+      } else {
+        .air
+      }
+    })
+    return chunk
+  }
+}