From 6d5e42f10bf62c7b1db9f73c86eafa9f9db33414 Mon Sep 17 00:00:00 2001
From: Joshua Yanovski <pythonesque@gmail.com>
Date: Sun, 26 Jan 2020 16:18:51 +0100
Subject: [PATCH] Better is_underwater() check.

Takes rivers into account somewhat, and doesn't take up extra space in
SimChunk.
---
 world/src/lib.rs     | 2 +-
 world/src/sim/mod.rs | 8 +++++---
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/world/src/lib.rs b/world/src/lib.rs
index 3745a84a1a..6954bbe4dd 100644
--- a/world/src/lib.rs
+++ b/world/src/lib.rs
@@ -152,7 +152,7 @@ impl World {
         let mut supplement = ChunkSupplement {
             entities: if rand::thread_rng().gen::<f32>() < SPAWN_RATE
                 && sim_chunk.chaos < 0.5
-                && !sim_chunk.is_underwater
+                && !sim_chunk.is_underwater()
             {
                 vec![EntityInfo {
                     pos: gen_entity_pos(),
diff --git a/world/src/sim/mod.rs b/world/src/sim/mod.rs
index b7be46d288..2bb51baf21 100644
--- a/world/src/sim/mod.rs
+++ b/world/src/sim/mod.rs
@@ -1475,7 +1475,7 @@ impl WorldSim {
 
                     let new_chunk = this.get(downhill_pos)?;
                     const SLIDE_THRESHOLD: f32 = 5.0;
-                    if new_chunk.is_underwater || new_chunk.alt + SLIDE_THRESHOLD < chunk.alt {
+                    if new_chunk.is_underwater() || new_chunk.alt + SLIDE_THRESHOLD < chunk.alt {
                         break;
                     } else {
                         chunk = new_chunk;
@@ -1720,7 +1720,6 @@ pub struct SimChunk {
     pub spawn_rate: f32,
     pub location: Option<LocationInfo>,
     pub river: RiverData,
-    pub is_underwater: bool,
 
     pub structures: Structures,
     pub contains_waypoint: bool,
@@ -1898,7 +1897,6 @@ impl SimChunk {
             } else {
                 0.0
             },
-            is_underwater,
             is_cliffs: cliff > 0.5 && !is_underwater,
             near_cliffs: cliff > 0.2,
             tree_density,
@@ -1971,6 +1969,10 @@ impl SimChunk {
         }
     }
 
+    pub fn is_underwater(&self) -> bool {
+        self.river.river_kind.is_some()
+    }
+
     pub fn get_base_z(&self) -> f32 {
         self.alt - self.chaos * 50.0 - 16.0
     }