tower world gen

Sources/Voxelotl/Generator/StandardWorldGenerator.swift

@@ -0,0 +1,38 @@
+struct StandardWorldGenerator: WorldGenerator {
+  var noise: ImprovedPerlin<Float>!, noise2: SimplexNoise<Float>!
+
+  public mutating func reset(seed: UInt64) {
+    var random: any RandomProvider
+    let initialState = SplitMix64.createState(seed: seed)
+#if true
+    random = Xoroshiro128PlusPlus(state: initialState)
+#else
+    random = PCG32Random(seed: initialState)
+#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 / 16.0
+          + 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:        Float(180 + self.noise2.get(fpos * 0.05) * 180),
+          saturation: Float(0.5 + self.noise2.get(SIMD4(fpos * 0.05, 4)) * 0.5),
+          value:      Float(0.5 + self.noise2.get(SIMD4(fpos * 0.05, 9)) * 0.5).lerp(0.5, 1)).linear)
+      } else {
+        .air
+      }
+    })
+    return chunk
+  }
+}