Biome blending

Dithering to biome edges

engine/world_generation/src/map/biome_map.rs

@@ -1,4 +1,5 @@
 use bevy::math::{UVec2, Vec3};
+use noise::NoiseFn;
 use rayon::iter::{IntoParallelIterator, ParallelIterator};
 
 use super::chunk::Chunk;
@@ -120,6 +121,15 @@ impl BiomeMap {
 		return Some(chunk.get_biome(x as usize - cx * Chunk::SIZE, y as usize - cy * Chunk::SIZE));
 	}
 
+	pub fn get_biome_id(&self, x: usize, y: usize) -> usize {
+		let cx = (x as f32 / Chunk::SIZE as f32).floor() as usize;
+		let cy = (y as f32 / Chunk::SIZE as f32).floor() as usize;
+
+		let chunk = &self.chunks[cx + cy * self.size.x as usize];
+
+		return chunk.get_biome_id(x - (cx * Chunk::SIZE), y - (cy * Chunk::SIZE));
+	}
+
 	pub fn get_biome_data(&self, x: usize, y: usize) -> &BiomeData {
 		let cx = (x as f32 / Chunk::SIZE as f32).floor() as usize;
 		let cy = (y as f32 / Chunk::SIZE as f32).floor() as usize;
@@ -145,6 +155,37 @@ impl BiomeChunk {
 	pub fn get_biome_data(&self, x: usize, y: usize) -> &BiomeData {
 		return &self.data[x + y * Chunk::SIZE];
 	}
+
+	pub fn get_biome_id(&self, x: usize, y: usize) -> usize {
+		let b = self.get_biome(x, y);
+		let mut max = 0.;
+		let mut idx = 0;
+		for i in 0..b.len() {
+			let blend = b[i];
+			if blend > max {
+				max = blend;
+				idx = i;
+			}
+		}
+		return idx;
+	}
+
+	pub fn get_biome_id_dithered(&self, x: usize, y: usize, noise: &impl NoiseFn<f64, 2>, scale: f64) -> usize {
+		let cur_id = self.get_biome_id(x, y);
+		let b = self.get_biome(x, y);
+		let n = (noise.get([x as f64 / scale, y as f64 / scale]) as f32) * b[cur_id];
+		for i in 0..b.len() {
+			let blend = b[i];
+			if blend == 0. {
+				continue;
+			}
+			if n < blend {
+				return i;
+			}
+		}
+
+		return cur_id;
+	}
 }
 
 #[cfg(test)]