Add simple world generator

src/voxel.rs

@@ -1,4 +1,5 @@
 pub mod brickmap;
 mod voxel_renderer;
+pub mod world;
 
 pub use voxel_renderer::*;

src/voxel/world.rs

@@ -0,0 +1,122 @@
+use crate::math;
+use std::collections::HashMap;
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+pub enum Voxel {
+    Empty,
+    Color(u8, u8, u8),
+}
+
+#[derive(Debug)]
+pub struct Chunk {
+    pos: glam::IVec3,
+    noise: Vec<f32>,
+    blocks: Vec<Vec<Voxel>>,
+}
+
+impl Chunk {
+    fn get_block(&mut self, pos: glam::UVec3) -> Vec<Voxel> {
+        let chunk_dims = glam::uvec3(32, 32, 32);
+        let noise_dims = chunk_dims + glam::uvec3(1, 1, 1);
+        let block_idx = math::to_1d_index(pos, chunk_dims);
+        assert_eq!(self.blocks.len(), 32768);
+        let block = &mut self.blocks[block_idx];
+
+        if block.len() == 0 {
+            // Extract relevant noise values from the chunk
+            let mut noise_vals = Vec::new();
+            for z in 0..2 {
+                for y in 0..2 {
+                    for x in 0..2 {
+                        let noise_pos = glam::uvec3(x, y, z) + pos;
+                        let noise_idx = math::to_1d_index(noise_pos, noise_dims);
+                        noise_vals.push(self.noise[noise_idx]);
+                    }
+                }
+            }
+
+            // Interpolate to get block voxels
+            for z in 0..8 {
+                for y in 0..8 {
+                    for x in 0..8 {
+                        let dx = x as f32 / 7.0;
+                        let dy = y as f32 / 7.0;
+                        let dz = z as f32 / 7.0;
+
+                        let val = math::tri_lerp(&noise_vals, &[dx, dy, dz]);
+
+                        // TODO: Some fancier way to determine voxel type and colour
+                        if val > 0.0 {
+                            let r = ((x + 1) * 32 - 1) as u8;
+                            let g = ((y + 1) * 32 - 1) as u8;
+                            let b = ((z + 1) * 32 - 1) as u8;
+                            block.push(Voxel::Color(r, g, b));
+                        } else {
+                            block.push(Voxel::Empty);
+                        }
+                    }
+                }
+            }
+        }
+
+        block.to_owned()
+    }
+}
+
+#[derive(Debug, Clone, Copy)]
+pub struct GenerationSettings {
+    pub seed: i32,
+    pub frequency: f32,
+    pub octaves: u8,
+    pub gain: f32,
+    pub lacunarity: f32,
+}
+
+pub struct WorldManager {
+    settings: GenerationSettings,
+    chunks: HashMap<glam::IVec3, Chunk>,
+}
+
+impl WorldManager {
+    pub fn new(settings: GenerationSettings) -> Self {
+        let chunks = HashMap::new();
+        Self { settings, chunks }
+    }
+
+    pub fn get_block(&mut self, chunk_pos: glam::IVec3, local_pos: glam::UVec3) -> Vec<Voxel> {
+        // There's no world saving yet, so if a chunk isn't currently loaded we need to
+        // generate it's base noise values
+        if !self.chunks.contains_key(&chunk_pos) {
+            let new_chunk = self.gen_chunk(chunk_pos);
+            self.chunks.insert(chunk_pos, new_chunk);
+        }
+
+        let chunk = self.chunks.get_mut(&chunk_pos).unwrap();
+        chunk.get_block(local_pos)
+    }
+
+    fn gen_chunk(&mut self, pos: glam::IVec3) -> Chunk {
+        // We use dimensions of 33 because the corners on the last chunk block of each
+        // axis step outside of our 0..32 bounds, sharing a value with the neighbouring
+        // chunk
+        let noise = simdnoise::NoiseBuilder::fbm_3d_offset(
+            pos.x as f32,
+            33,
+            pos.y as f32,
+            33,
+            pos.z as f32,
+            33,
+        )
+        .with_seed(self.settings.seed)
+        .with_freq(self.settings.frequency)
+        .with_octaves(self.settings.octaves)
+        .with_gain(self.settings.gain)
+        .with_lacunarity(self.settings.lacunarity)
+        .generate()
+        .0;
+
+        let mut blocks = Vec::with_capacity(32768);
+        blocks.resize(blocks.capacity(), vec![]);
+        Chunk { pos, noise, blocks }
+    }
+}