From e59f1e8d282916a916d4636a26bbd6880e4605ad Mon Sep 17 00:00:00 2001
From: Ygor Souza <ygor.souza@protonmail.com>
Date: Thu, 22 Apr 2021 21:12:35 +0200
Subject: [PATCH] Skip physics pass for arrows stuck on surfaces

This keeps the arrow velocity from changing, which is what was causing
the ProjectileHit outcome to be pushed multiple times for the same
arrow, since the outcome checks if the arrow velocity is above a given
threshold.
---
 common/systems/src/phys.rs | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/common/systems/src/phys.rs b/common/systems/src/phys.rs
index 83bb7975f0..80d881fdab 100644
--- a/common/systems/src/phys.rs
+++ b/common/systems/src/phys.rs
@@ -562,6 +562,7 @@ impl<'a> PhysicsData<'a> {
         (
             positions,
             velocities,
+            read.stickies.maybe(),
             &read.bodies,
             &write.physics_states,
             &read.masses,
@@ -574,14 +575,17 @@ impl<'a> PhysicsData<'a> {
                     prof_span!(guard, "velocity update rayon job");
                     guard
                 },
-                |_guard, (pos, vel, body, physics_state, mass, density, _)| {
+                |_guard, (pos, vel, sticky, body, physics_state, mass, density, _)| {
                     let in_loaded_chunk = read
                         .terrain
                         .get_key(read.terrain.pos_key(pos.0.map(|e| e.floor() as i32)))
                         .is_some();
 
                     // Apply physics only if in a loaded chunk
-                    if in_loaded_chunk {
+                    if in_loaded_chunk
+                    // And not already stuck on a block (e.g., for arrows)
+                    && !(physics_state.on_surface().is_some() && sticky.is_some())
+                    {
                         // Clamp dt to an effective 10 TPS, to prevent gravity from slamming the
                         // players into the floor when stationary if other systems cause the server
                         // to lag (as observed in the 0.9 release party).