From 9e35f5ec3334d7b4488ca6b1c56b21e8c7835ec1 Mon Sep 17 00:00:00 2001
From: Ben Wallis <atomyc@gmail.com>
Date: Fri, 20 Aug 2021 08:44:34 +0100
Subject: [PATCH] Explosions no longer change block colours within the radius
 of a safe zone. Doubled the radius of the safe zone in the /home town.

---
 CHANGELOG.md                             |  2 ++
 server/src/events/entity_manipulation.rs | 45 +++++++++++++++++++++---
 server/src/sys/terrain.rs                |  4 ++-
 3 files changed, 46 insertions(+), 5 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index b3379ab9f1..e1c44314a2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -31,6 +31,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Can now tilt glider while only wielding it
 - Experimental terrain persistence (see server documentation)
 - Add GPU filtering using WGPU_ADAPTER environment variable
+- Explosions no longer change block colours within safe zones
 
 ### Changed
 
@@ -53,6 +54,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Glider dimensions now depend on character height
 - Glider dimensions somewhat increased overall
 - Dungeon difficulty level starts at 1 instead of 0
+- The radius of the safe zone around the starting town has been doubled
 
 ### Removed
 
diff --git a/server/src/events/entity_manipulation.rs b/server/src/events/entity_manipulation.rs
index 5c90d6f24e..75074402df 100644
--- a/server/src/events/entity_manipulation.rs
+++ b/server/src/events/entity_manipulation.rs
@@ -4,9 +4,10 @@ use crate::{
         agent::{Agent, AgentEvent, Sound, SoundKind},
         biped_large, bird_large, quadruped_low, quadruped_medium, quadruped_small,
         skills::SkillGroupKind,
-        theropod, PhysicsState,
+        theropod, BuffKind, BuffSource, PhysicsState,
     },
     rtsim::RtSim,
+    sys::terrain::SAFE_ZONE_RADIUS,
     Server, SpawnPoint, StateExt,
 };
 use common::{
@@ -16,8 +17,9 @@ use common::{
         self, aura, buff,
         chat::{KillSource, KillType},
         inventory::item::MaterialStatManifest,
-        object, Alignment, Body, CharacterState, Energy, EnergyChange, Group, Health, HealthChange,
-        HealthSource, Inventory, Player, Poise, PoiseChange, PoiseSource, Pos, SkillSet, Stats,
+        object, Alignment, Auras, Body, CharacterState, Energy, EnergyChange, Group, Health,
+        HealthChange, HealthSource, Inventory, Player, Poise, PoiseChange, PoiseSource, Pos,
+        SkillSet, Stats,
     },
     event::{EventBus, ServerEvent},
     lottery::{LootSpec, Lottery},
@@ -741,11 +743,46 @@ pub fn handle_explosion(server: &Server, pos: Vec3<f32>, explosion: Explosion, o
 
     // TODO: Faster RNG?
     let mut rng = rand::thread_rng();
-    for effect in explosion.effects {
+    'effects: for effect in explosion.effects {
         match effect {
             RadiusEffect::TerrainDestruction(power) => {
                 const RAYS: usize = 500;
 
+                let spatial_grid = ecs.read_resource::<common::CachedSpatialGrid>();
+                let auras = ecs.read_storage::<Auras>();
+                let positions = ecs.read_storage::<Pos>();
+
+                // Prevent block colour changes within the radius of a safe zone aura
+                if spatial_grid
+                    .0
+                    .in_circle_aabr(pos.xy(), SAFE_ZONE_RADIUS)
+                    .filter_map(|entity| {
+                        auras
+                            .get(entity)
+                            .and_then(|entity_auras| {
+                                positions.get(entity).map(|pos| (entity_auras, pos))
+                            })
+                            .and_then(|(entity_auras, pos)| {
+                                entity_auras
+                                    .auras
+                                    .iter()
+                                    .find(|(_, aura)| {
+                                        matches!(aura.aura_kind, aura::AuraKind::Buff {
+                                            kind: BuffKind::Invulnerability,
+                                            source: BuffSource::World,
+                                            ..
+                                        })
+                                    })
+                                    .map(|(_, aura)| (*pos, aura.radius))
+                            })
+                    })
+                    .any(|(aura_pos, aura_radius)| {
+                        pos.distance_squared(aura_pos.0) < aura_radius.powi(2)
+                    })
+                {
+                    continue 'effects;
+                }
+
                 // Color terrain
                 let mut touched_blocks = Vec::new();
                 let color_range = power * 2.7;
diff --git a/server/src/sys/terrain.rs b/server/src/sys/terrain.rs
index de9ad0a201..d91a7fecc0 100644
--- a/server/src/sys/terrain.rs
+++ b/server/src/sys/terrain.rs
@@ -36,6 +36,8 @@ pub(crate) struct LazyTerrainMessage {
     lazy_msg_hi: Option<crate::client::PreparedMsg>,
 }
 
+pub const SAFE_ZONE_RADIUS: f32 = 200.0;
+
 impl LazyTerrainMessage {
     #[allow(clippy::new_without_default)]
     pub(crate) fn new() -> Self {
@@ -241,7 +243,7 @@ impl<'a> System<'a> for Sys {
             // Insert a safezone if chunk contains the spawn position
             if server_settings.safe_spawn && is_spawn_chunk(key, *spawn_point, &terrain) {
                 server_emitter.emit(ServerEvent::CreateSafezone {
-                    range: Some(100.0),
+                    range: Some(SAFE_ZONE_RADIUS),
                     pos: Pos(spawn_point.0),
                 });
             }