Only render the top block at each XZ cell

Description

We're rendering a lot of blocks that aren't visible because they are underground. To cut down on the amount of work the renderer has to do, we can just send the top block at each X-Z coordinate.

Commands

git clone git@github.com:atsheehan/iridium
cd iridium
git checkout fc5afbc329d4bb6d3b47de649af1888e99c0a6d8
cargo run --release

Code Changes

`Modified src/main.rsGitHub`

@@ -25,7 +25,7 @@
2525      let mut renderer = Renderer::new(&event_loop, options.windowed, options.disable_vsync);
2626  
2727      let mut world = World::new(256, 32, 256);
28-     renderer.update_block_cache(world.block_positions());
28+     renderer.update_block_cache(world.visible_block_positions());
2929  
3030      let mut last_instant = Instant::now();
3131      let mut fps_counter = FrameCounter::new(last_instant);

@@ -25,7 +25,7 @@
25      let mut renderer = Renderer::new(&event_loop, options.windowed, options.disable_vsync);
26  
27      let mut world = World::new(256, 32, 256);
28-     renderer.update_block_cache(world.block_positions());
29  
30      let mut last_instant = Instant::now();
31      let mut fps_counter = FrameCounter::new(last_instant);

@@ -25,7 +25,7 @@
25      let mut renderer = Renderer::new(&event_loop, options.windowed, options.disable_vsync);
26  
27      let mut world = World::new(256, 32, 256);
28+     renderer.update_block_cache(world.visible_block_positions());
29  
30      let mut last_instant = Instant::now();
31      let mut fps_counter = FrameCounter::new(last_instant);

`Modified src/world.rsGitHub`

@@ -53,13 +53,13 @@
5353          self.camera.position = self.camera.position + actual_velocity;
5454      }
5555  
56-     pub(crate) fn block_positions(&self) -> impl Iterator<Item = Vec3> + '_ {
56+     pub(crate) fn visible_block_positions(&self) -> impl Iterator<Item = Vec3> + '_ {
5757          (0..self.z_depth).flat_map(move |z| {
58-             (0..self.x_width).flat_map(move |x| {
58+             (0..self.x_width).map(move |x| {
5959                  let index = ((self.x_width * z) + x) as usize;
60-                 let y_max = self.heights[index];
60+                 let y = self.heights[index];
6161  
62-                 (0..y_max).map(move |y| Vec3(x as f32, y as f32, z as f32))
62+                 Vec3(x as f32, y as f32, z as f32)
6363              })
6464          })
6565      }

@@ -53,13 +53,13 @@
53          self.camera.position = self.camera.position + actual_velocity;
54      }
55  
56-     pub(crate) fn block_positions(&self) -> impl Iterator<Item = Vec3> + '_ {
57          (0..self.z_depth).flat_map(move |z| {
58-             (0..self.x_width).flat_map(move |x| {
59                  let index = ((self.x_width * z) + x) as usize;
60-                 let y_max = self.heights[index];
61  
62-                 (0..y_max).map(move |y| Vec3(x as f32, y as f32, z as f32))
63              })
64          })
65      }

@@ -53,13 +53,13 @@
53          self.camera.position = self.camera.position + actual_velocity;
54      }
55  
56+     pub(crate) fn visible_block_positions(&self) -> impl Iterator<Item = Vec3> + '_ {
57          (0..self.z_depth).flat_map(move |z| {
58+             (0..self.x_width).map(move |x| {
59                  let index = ((self.x_width * z) + x) as usize;
60+                 let y = self.heights[index];
61  
62+                 Vec3(x as f32, y as f32, z as f32)
63              })
64          })
65      }