From 8daebbdf2e553b756fcc5def8cedafd4e670bcc4 Mon Sep 17 00:00:00 2001
From: pionere <pionere@freemail.hu>
Date: Fri, 30 Aug 2024 08:16:46 +0200
Subject: [PATCH] fix bias in L4RoomGen

---
 Source/drlg_l4.cpp | 74 +++++++++++++++++++++++++++++++++-------------
 1 file changed, 54 insertions(+), 20 deletions(-)

diff --git a/Source/drlg_l4.cpp b/Source/drlg_l4.cpp
index 846c990f910..9e618edae5d 100644
--- a/Source/drlg_l4.cpp
+++ b/Source/drlg_l4.cpp
@@ -1365,7 +1365,6 @@ static bool L4CheckHHall(int y, int left, int w)
 static void L4RoomGen(int x, int y, int w, int h, bool dir)
 {
 	int dirProb, i, width, height, rx, ry, rxy2;
-	bool ran2;
 
 	dirProb = random_(0, 4);
 
@@ -1377,23 +1376,40 @@ static void L4RoomGen(int x, int y, int w, int h, bool dir)
 			ry = h / 2u + y - height / 2u;
 			rx = x - width;
 			if (L4CheckVHall(x, ry - 1, height + 2)
-			 && L4CheckRoom(rx - 1, ry - 1, width + 1, height + 2))  /// BUGFIX: swap args 3 and 4 ("ch+2" and "cw+1") (fixed)
+			 && L4CheckRoom(rx - 1, ry - 1, width + 1, height + 2)) { /// BUGFIX: swap args 3 and 4 ("ch+2" and "cw+1") (fixed)
+				// - add room to the left
+				L4DrawRoom(rx, ry, width, height);
 				break;
+			}
+		}
+		if (i != 0) {
+			// room added to the left -> force similar room on the right side
+			i = 1;
+		} else {
+			// room was not added to the left -> try more options on the right
+			rx = -1;
+			i = 20;
 		}
-
-		if (i != 0)
-			L4DrawRoom(rx, ry, width, height);
 		// try to place a room to the right
 		rxy2 = x + w;
-		ran2 = L4CheckVHall(rxy2 - 1, ry - 1, height + 2)
-			&& L4CheckRoom(rxy2, ry - 1, width + 1, height + 2);
-		if (ran2)
-			L4DrawRoom(rxy2, ry, width, height);
+		while(true) {
+			if (L4CheckVHall(rxy2 - 1, ry - 1, height + 2)
+			 && L4CheckRoom(rxy2, ry - 1, width + 1, height + 2)) {
+				// - add room to the right
+				L4DrawRoom(rxy2, ry, width, height);
+				break;
+			}
+			if (--i == 0)
+				break;
+			width = RandRange(2, 6) & ~1;
+			height = RandRange(2, 6) & ~1;
+			ry = h / 2u + y - height / 2u;
+		}
 		// proceed with the placed a room on the left
-		if (i != 0)
+		if (rx >= 0)
 			L4RoomGen(rx, ry, width, height, true);
 		// proceed with the placed a room on the right
-		if (ran2)
+		if (i != 0)
 			L4RoomGen(rxy2, ry, width, height, true);
 	} else {
 		// try to place a room to the top
@@ -1403,23 +1419,41 @@ static void L4RoomGen(int x, int y, int w, int h, bool dir)
 			rx = w / 2u + x - width / 2u;
 			ry = y - height;
 			if (L4CheckHHall(y, rx - 1, width + 2)
-			 && L4CheckRoom(rx - 1, ry - 1, width + 2, height + 1))
+			 && L4CheckRoom(rx - 1, ry - 1, width + 2, height + 1)) {
+				// - add room to the top
+				L4DrawRoom(rx, ry, width, height);
 				break;
+			}
 		}
 
-		if (i != 0)
-			L4DrawRoom(rx, ry, width, height);
+		if (i != 0) {
+			// room added to the top -> force similar room on the bottom side
+			i = 1;
+		} else {
+			// room was not added to the top -> try more options on the bottom
+			ry = -1;
+			i = 20;
+		}
 		// try to place a room to the bottom
 		rxy2 = y + h;
-		ran2 = L4CheckHHall(rxy2 - 1, rx - 1, width + 2)
-			&& L4CheckRoom(rx - 1, rxy2, width + 2, height + 1);
-		if (ran2)
-			L4DrawRoom(rx, rxy2, width, height);
+		while(true) {
+			if (L4CheckHHall(rxy2 - 1, rx - 1, width + 2)
+			 && L4CheckRoom(rx - 1, rxy2, width + 2, height + 1)) {
+				// - add room to the bottom
+				L4DrawRoom(rx, rxy2, width, height);
+				break;
+			}
+			if (--i == 0)
+				break;
+			width = RandRange(2, 6) & ~1;
+			height = RandRange(2, 6) & ~1;
+			rx = w / 2u + x - width / 2u;
+		}
 		// proceed with the placed a room on the top
-		if (i != 0)
+		if (ry >= 0)
 			L4RoomGen(rx, ry, width, height, false);
 		// proceed with the placed a room on the bottom
-		if (ran2)
+		if (i != 0)
 			L4RoomGen(rx, rxy2, width, height, false);
 	}
 }