Create terrain from heightmap

Description

Using random heights for each block was too noisy.

We can define a function that defines a heightmap. The function can approximate curves and hills.

Screenshot

Commands

git clone git@github.com:atsheehan/iridium
cd iridium
git checkout ada7c1e86522e0542538cb72556ed9a769c0cdb0
cargo run --release

Code Changes

`Modified src/main.rsGitHub`

@@ -24,7 +24,7 @@
2424      let event_loop = EventLoop::new().unwrap();
2525      let mut renderer = Renderer::new(&event_loop, options.windowed);
2626  
27-     let mut world = World::new(100, 100, 100);
27+     let mut world = World::new(100, 25, 100);
2828      renderer.update_block_cache(world.block_positions());
2929  
3030      let mut last_instant = Instant::now();

@@ -24,7 +24,7 @@
24      let event_loop = EventLoop::new().unwrap();
25      let mut renderer = Renderer::new(&event_loop, options.windowed);
26  
27-     let mut world = World::new(100, 100, 100);
28      renderer.update_block_cache(world.block_positions());
29  
30      let mut last_instant = Instant::now();

@@ -24,7 +24,7 @@
24      let event_loop = EventLoop::new().unwrap();
25      let mut renderer = Renderer::new(&event_loop, options.windowed);
26  
27+     let mut world = World::new(100, 25, 100);
28      renderer.update_block_cache(world.block_positions());
29  
30      let mut last_instant = Instant::now();

`Modified src/math.rsGitHub`

@@ -1,6 +1,9 @@
11  use std::ops::Add;
22  
33  #[derive(Debug, Copy, Clone)]
4+ pub(crate) struct Vec2(pub(crate) f32, pub(crate) f32);
5+ 
6+ #[derive(Debug, Copy, Clone)]
47  pub(crate) struct Vec3(pub(crate) f32, pub(crate) f32, pub(crate) f32);
58  
69  impl Vec3 {
@@ -40,6 +43,10 @@
4043      pub(crate) fn z(&self) -> f32 {
4144          self.2
4245      }
46+ 
47+     pub(crate) fn xz(&self) -> Vec2 {
48+         Vec2(self.0, self.2)
49+     }
4350  }
4451  
4552  impl Add<Vec3> for Vec3 {

@@ -1,6 +1,9 @@
1  use std::ops::Add;
2  
3  #[derive(Debug, Copy, Clone)]
 
 
 
4  pub(crate) struct Vec3(pub(crate) f32, pub(crate) f32, pub(crate) f32);
5  
6  impl Vec3 {
@@ -40,6 +43,10 @@
40      pub(crate) fn z(&self) -> f32 {
41          self.2
42      }
 
 
 
 
43  }
44  
45  impl Add<Vec3> for Vec3 {

@@ -1,6 +1,9 @@
1  use std::ops::Add;
2  
3  #[derive(Debug, Copy, Clone)]
4+ pub(crate) struct Vec2(pub(crate) f32, pub(crate) f32);
5+ 
6+ #[derive(Debug, Copy, Clone)]
7  pub(crate) struct Vec3(pub(crate) f32, pub(crate) f32, pub(crate) f32);
8  
9  impl Vec3 {
@@ -40,6 +43,10 @@
43      pub(crate) fn z(&self) -> f32 {
44          self.2
45      }
46+ 
47+     pub(crate) fn xz(&self) -> Vec2 {
48+         Vec2(self.0, self.2)
49+     }
50  }
51  
52  impl Add<Vec3> for Vec3 {

`Modified src/world.rsGitHub`

@@ -1,6 +1,6 @@
1- use crate::math::{RandomNumberGenerator, Vec3};
1+ use crate::math::{Vec2, Vec3};
22  
3- const MOUSE_SENSITIVITY: f32 = 0.001;
3+ const MOUSE_SENSITIVITY: f32 = 0.01;
44  const MOVE_SPEED: f32 = 0.5;
55  
66  pub(crate) struct World {
@@ -21,13 +21,23 @@
2121              pitch: 0.0,
2222          };
2323  
24-         let mut rng = RandomNumberGenerator::with_seed(42);
2524          let xz_area = (x_width * z_depth) as usize;
2625  
26+         let heightmap = Heightmap::new(Vec2((x_width / 2) as f32, (z_depth / 2) as f32), 25.0);
27+         let min_height = 1;
28+         let height_range = y_height - min_height;
29+ 
2730          let mut heights = Vec::with_capacity(xz_area);
31+         for x in 0..x_width {
32+             for z in 0..z_depth {
33+                 let coordinate = Coordinates(x, 0, z);
34+                 let xz_position = coordinate.center().xz();
35+ 
36+                 let height = heightmap.height_at(xz_position.0, xz_position.1);
37+                 let scaled_height = (height * height_range as f32) as u32 + min_height;
2838  
29-         for _ in 0..xz_area {
30-             heights.push(rng.gen_range(1, y_height));
39+                 heights.push(scaled_height);
40+             }
3141          }
3242  
3343          Self {
@@ -136,3 +146,38 @@
136146          self.pitch
137147      }
138148  }
149+ 
150+ /// Describes how elevation varies across the x-z plane.
151+ struct Heightmap {
152+     center: Vec2,
153+     spread: f32,
154+ }
155+ 
156+ impl Heightmap {
157+     fn new(center: Vec2, spread: f32) -> Self {
158+         Self { center, spread }
159+     }
160+ 
161+     fn height_at(&self, x: f32, z: f32) -> f32 {
162+         let Vec2(x_center, z_center) = self.center;
163+         let spread = self.spread * self.spread * 2.0;
164+ 
165+         let dx = x_center - x;
166+         let dz = z_center - z;
167+ 
168+         let x_term = (dx * dx) / spread;
169+         let z_term = (dz * dz) / spread;
170+ 
171+         let sum = -(x_term + z_term);
172+         sum.exp()
173+     }
174+ }
175+ 
176+ struct Coordinates(u32, u32, u32);
177+ 
178+ impl Coordinates {
179+     fn center(&self) -> Vec3 {
180+         let Self(x, y, z) = *self;
181+         Vec3(x as f32 + 0.5, y as f32 + 0.5, z as f32 + 0.5)
182+     }
183+ }

@@ -1,6 +1,6 @@
1- use crate::math::{RandomNumberGenerator, Vec3};
2  
3- const MOUSE_SENSITIVITY: f32 = 0.001;
4  const MOVE_SPEED: f32 = 0.5;
5  
6  pub(crate) struct World {
@@ -21,13 +21,23 @@
21              pitch: 0.0,
22          };
23  
24-         let mut rng = RandomNumberGenerator::with_seed(42);
25          let xz_area = (x_width * z_depth) as usize;
26  
 
 
 
 
27          let mut heights = Vec::with_capacity(xz_area);
 
 
 
 
 
 
 
28  
29-         for _ in 0..xz_area {
30-             heights.push(rng.gen_range(1, y_height));
31          }
32  
33          Self {
@@ -136,3 +146,38 @@
136          self.pitch
137      }
138  }

@@ -1,6 +1,6 @@
1+ use crate::math::{Vec2, Vec3};
2  
3+ const MOUSE_SENSITIVITY: f32 = 0.01;
4  const MOVE_SPEED: f32 = 0.5;
5  
6  pub(crate) struct World {
@@ -21,13 +21,23 @@
21              pitch: 0.0,
22          };
23  
 
24          let xz_area = (x_width * z_depth) as usize;
25  
26+         let heightmap = Heightmap::new(Vec2((x_width / 2) as f32, (z_depth / 2) as f32), 25.0);
27+         let min_height = 1;
28+         let height_range = y_height - min_height;
29+ 
30          let mut heights = Vec::with_capacity(xz_area);
31+         for x in 0..x_width {
32+             for z in 0..z_depth {
33+                 let coordinate = Coordinates(x, 0, z);
34+                 let xz_position = coordinate.center().xz();
35+ 
36+                 let height = heightmap.height_at(xz_position.0, xz_position.1);
37+                 let scaled_height = (height * height_range as f32) as u32 + min_height;
38  
39+                 heights.push(scaled_height);
40+             }
41          }
42  
43          Self {
@@ -136,3 +146,38 @@
146          self.pitch
147      }
148  }
149+ 
150+ /// Describes how elevation varies across the x-z plane.
151+ struct Heightmap {
152+     center: Vec2,
153+     spread: f32,
154+ }
155+ 
156+ impl Heightmap {
157+     fn new(center: Vec2, spread: f32) -> Self {
158+         Self { center, spread }
159+     }
160+ 
161+     fn height_at(&self, x: f32, z: f32) -> f32 {
162+         let Vec2(x_center, z_center) = self.center;
163+         let spread = self.spread * self.spread * 2.0;
164+ 
165+         let dx = x_center - x;
166+         let dz = z_center - z;
167+ 
168+         let x_term = (dx * dx) / spread;
169+         let z_term = (dz * dz) / spread;
170+ 
171+         let sum = -(x_term + z_term);
172+         sum.exp()
173+     }
174+ }
175+ 
176+ struct Coordinates(u32, u32, u32);
177+ 
178+ impl Coordinates {
179+     fn center(&self) -> Vec3 {
180+         let Self(x, y, z) = *self;
181+         Vec3(x as f32 + 0.5, y as f32 + 0.5, z as f32 + 0.5)
182+     }
183+ }