Implement SectionLightData

minecraft-server/src/world/light.rs

@@ -0,0 +1,80 @@
+use crate::prelude::*;
+use super::*;
+
+const MAX_LIGHT_LEVEL: u8 = 15;
+
+#[derive(Debug, Clone)]
+struct SectionLightData(Vec<u8>); // TODO(optimization): Use simd 
+
+impl SectionLightData {
+    pub fn new() -> SectionLightData {
+        SectionLightData(vec![0; 2048])
+    }
+
+    pub fn set_with(&mut self, level: u8) {
+        let level = level << 4 | level;
+        self.0.iter_mut().for_each(|v| *v = level);
+    }
+
+
+    /// Get the light level at the given position.
+    pub fn get(&self, postion: BlockPositionInChunk) -> Result<u8, ()> {
+        let (x, y, z) = (postion.bx as usize, postion.by as usize, postion.bz as usize);
+        let index = (y << 8) | (z << 4) | x;
+        let byte_index = index >> 1;
+
+        if byte_index >= 2048 {
+            return Err(());
+        }
+
+        if index & 1 == 0 {
+            Ok(self.0[byte_index] & 0x0F)
+        } else {
+            Ok((self.0[byte_index] & 0xF0) >> 4)
+        }
+    }
+
+    /// Set the light level at the given position.
+    pub fn set(&mut self, postion: BlockPositionInChunk, level: u8) -> Result<(), ()> {
+        if level > MAX_LIGHT_LEVEL {
+            return Err(());
+        }
+
+        let (x, y, z) = (postion.bx as usize, postion.by as usize, postion.bz as usize);
+        let index = (y << 8) | (z << 4) | x;
+        let byte_index = index >> 1;
+
+        if byte_index >= 2048 {
+            return Err(());
+        }
+
+        if index & 1 == 0 {
+            self.0[byte_index] = (self.0[byte_index] & 0xF0) | (level & 0x0F);
+        } else {
+            self.0[byte_index] = (self.0[byte_index] & 0x0F) | ((level & 0x0F) << 4);
+        }
+
+        Ok(())
+    }
+
+    /// Set the light level at the given layer to the given level.
+    pub(super) fn set_layer(&mut self, layer: u8 , level: u8) -> Result<(), ()> {
+        if level > MAX_LIGHT_LEVEL {
+            return Err(());
+        }
+
+        if layer > MAX_LIGHT_LEVEL {
+            return Err(());
+        }
+
+        let level = level << 4 | level;
+        let layer = layer as usize;
+
+        // Because a layer is 16x16 blocks, we can just set 128 blocks at once and the y coordinate is the most significant bit of the index. 
+        for i in layer*128..(layer+1)*128 {
+            self.0[i] = level;
+        }
+
+        Ok(())
+    }
+}

minecraft-server/src/world/mod.rs

@@ -6,6 +6,8 @@ mod loading_manager;
 use loading_manager::*;
 mod map;
 use map::*;
+mod light;
+use light::*;
 mod ecs;
 use ecs::*;
 mod collisions;