From b0c9a8024e7e1882b3a87fb0473f69db70f87d33 Mon Sep 17 00:00:00 2001
From: zaid-ismail031 <ab1cd2eefre3@gmail.com>
Date: Mon, 29 Aug 2022 23:10:35 +0200
Subject: [PATCH] Refactor missiles.cpp to use Direction enum instead of magic
 Point/Displacement constants.

---
 Source/automap.cpp             |  2 ++
 Source/engine/direction.hpp    |  1 +
 Source/engine/displacement.hpp |  2 ++
 Source/missiles.cpp            | 56 +++++++++++++++++++++++++++-------
 Source/monster.cpp             |  2 ++
 5 files changed, 52 insertions(+), 11 deletions(-)

diff --git a/Source/automap.cpp b/Source/automap.cpp
index de6a58a0a..548a09f31 100644
--- a/Source/automap.cpp
+++ b/Source/automap.cpp
@@ -468,6 +468,8 @@ void DrawAutomapPlr(const Surface &out, const Displacement &myPlayerOffset, int
 		DrawHorizontalLine(out, point, AmLine(8) + 1, playerColor);
 		DrawMapLineSteepSE(out, point, AmLine(4), playerColor);
 	} break;
+	case Direction::NoDirection:
+	break;
 	}
 }
 
diff --git a/Source/engine/direction.hpp b/Source/engine/direction.hpp
index 4738e8791..b9a42d061 100644
--- a/Source/engine/direction.hpp
+++ b/Source/engine/direction.hpp
@@ -16,6 +16,7 @@ enum class Direction : std::uint8_t {
 	NorthEast,
 	East,
 	SouthEast,
+	NoDirection
 };
 
 /** Maps from direction to a left turn from the direction. */
diff --git a/Source/engine/displacement.hpp b/Source/engine/displacement.hpp
index 341433498..6d04d5a51 100644
--- a/Source/engine/displacement.hpp
+++ b/Source/engine/displacement.hpp
@@ -244,6 +244,8 @@ private:
 			return { 1, -1 };
 		case Direction::SouthEast:
 			return { 1, 0 };
+		case Direction::NoDirection:
+			return { 0, 0 };
 		default:
 			return { 0, 0 };
 		}
diff --git a/Source/missiles.cpp b/Source/missiles.cpp
index 7c2aa79c8..9adbc2cae 100644
--- a/Source/missiles.cpp
+++ b/Source/missiles.cpp
@@ -16,6 +16,7 @@
 #endif
 #include "engine/load_file.hpp"
 #include "engine/random.hpp"
+#include "engine/points_in_rectangle_range.hpp"
 #include "init.h"
 #include "inv.h"
 #include "levels/trigs.h"
@@ -1442,9 +1443,11 @@ void AddRuneExplosion(Missile &missile, const AddMissileParameter & /*parameter*
 
 		missile._midam = dmg;
 
-		constexpr Displacement Offsets[] = { { -1, -1 }, { 0, -1 }, { 1, -1 }, { -1, 0 }, { 0, 0 }, { 1, 0 }, { -1, 1 }, { 0, 1 }, { 1, 1 } };
-		for (Displacement offset : Offsets)
-			CheckMissileCol(missile, dmg, dmg, false, missile.position.tile + offset, true);
+		auto searchArea = PointsInRectangleRangeColMajor { 
+			Rectangle { missile.position.tile, 1 } 
+		};
+		for (Point position : searchArea)
+			CheckMissileCol(missile, dmg, dmg, false, position, true);
 	}
 	missile._mlid = AddLight(missile.position.start, 8);
 	SetMissDir(missile, 0);
@@ -2976,8 +2979,18 @@ void MI_Fireball(Missile &missile)
 			const Point missilePosition = missile.position.tile;
 			ChangeLight(missile._mlid, missile.position.tile, missile._miAnimFrame);
 
-			constexpr Displacement Offsets[] = { { 0, 0 }, { 0, 1 }, { 0, -1 }, { 1, 0 }, { 1, -1 }, { 1, 1 }, { -1, 0 }, { -1, 1 }, { -1, -1 } };
-			for (Displacement offset : Offsets) {
+			constexpr Direction Offsets[] = { 
+				Direction::NoDirection, 
+				Direction::SouthWest, 
+				Direction::NorthEast, 
+				Direction::SouthEast, 
+				Direction::East, 
+				Direction::South, 
+				Direction::NorthWest, 
+				Direction::West, 
+				Direction::North 
+			};
+			for (Direction offset : Offsets) {
 				if (!CheckBlock(missile.position.start, missilePosition + offset))
 					CheckMissileCol(missile, minDam, maxDam, false, missilePosition + offset, true);
 			}
@@ -3314,8 +3327,15 @@ void MI_Flash(Missile &missile)
 	}
 	missile._mirange--;
 
-	constexpr Displacement Offsets[] = { { -1, 0 }, { 0, 0 }, { 1, 0 }, { -1, 1 }, { 0, 1 }, { 1, 1 } };
-	for (Displacement offset : Offsets)
+	constexpr Direction Offsets[] = { 
+		Direction::NorthWest, 
+		Direction::NoDirection, 
+		Direction::SouthEast, 
+		Direction::West, 
+		Direction::SouthWest,
+		Direction::South 
+	};
+	for (Direction offset : Offsets)
 		CheckMissileCol(missile, missile._midam, missile._midam, true, missile.position.tile + offset, true);
 
 	if (missile._mirange == 0) {
@@ -3336,8 +3356,12 @@ void MI_Flash2(Missile &missile)
 	}
 	missile._mirange--;
 
-	constexpr Displacement Offsets[] = { { -1, -1 }, { 0, -1 }, { 1, -1 } };
-	for (Displacement offset : Offsets)
+	constexpr Direction Offsets[] = { 
+		Direction::North, 
+		Direction::North, 
+		Direction::East
+	};
+	for (Direction offset : Offsets)
 		CheckMissileCol(missile, missile._midam, missile._midam, true, missile.position.tile + offset, true);
 
 	if (missile._mirange == 0) {
@@ -3925,8 +3949,18 @@ void MI_Element(Missile &missile)
 		ChangeLight(missile._mlid, missile.position.tile, missile._miAnimFrame);
 
 		Point startPoint = missile.var3 == 2 ? Point { missile.var4, missile.var5 } : Point(missile.position.start);
-		constexpr Displacement Offsets[] = { { 0, 0 }, { 0, 1 }, { 0, -1 }, { 1, 0 }, { 1, -1 }, { 1, 1 }, { -1, 0 }, { -1, 1 }, { -1, -1 } };
-		for (Displacement offset : Offsets) {
+		constexpr Direction Offsets[] = { 
+			Direction::NoDirection, 
+			Direction::SouthWest, 
+			Direction::NorthEast, 
+			Direction::SouthEast, 
+			Direction::East, 
+			Direction::South, 
+			Direction::NorthWest, 
+			Direction::West, 
+			Direction::North
+		};
+		for (Direction offset : Offsets) {
 			if (!CheckBlock(startPoint, missilePosition + offset))
 				CheckMissileCol(missile, dam, dam, true, missilePosition + offset, true);
 		}
diff --git a/Source/monster.cpp b/Source/monster.cpp
index 10a44b1a8..ea0ebf131 100644
--- a/Source/monster.cpp
+++ b/Source/monster.cpp
@@ -3832,6 +3832,8 @@ bool Walk(Monster &monster, Direction md)
 	case Direction::NorthWest:
 		WalkNorthwards(monster, -1, 0, Direction::NorthWest);
 		break;
+	case Direction::NoDirection:
+		break;
 	}
 	return true;
 }