From c9baa9867c31e5d60e5a7691ed3e3aa5102a5baa Mon Sep 17 00:00:00 2001
From: Thanasis Antoniou
Date: Thu, 11 Jul 2019 07:25:39 +0300
Subject: BLADERUNNER: Possible fix for facing angle assertion fault

---
 engines/bladerunner/actor.cpp      |  8 ++++++++
 engines/bladerunner/actor_walk.cpp | 12 ++++++++++++
 2 files changed, 20 insertions(+)

(limited to 'engines/bladerunner')

diff --git a/engines/bladerunner/actor.cpp b/engines/bladerunner/actor.cpp
index 5a464394f8..62ffd6f3a1 100644
--- a/engines/bladerunner/actor.cpp
+++ b/engines/bladerunner/actor.cpp
@@ -1298,9 +1298,17 @@ bool Actor::findEmptyPositionAround(const Vector3 &startPosition, const Vector3
 			}
 		} else { // looks like a bug as it might not find anything when there is no walkbox at this angle
 			facingLeft += 20;
+#if BLADERUNNER_ORIGINAL_BUGS
 			if (facingLeft > 1024) {
 				facingLeft -= 1024;
 			}
+#else
+			// if facingLeft + 20 == 1024 then it could cause the assertion fault
+			// in common/sinetables.cpp for SineTable::at(int index) -> assert((index >= 0) && (index < _nPoints))
+			if (facingLeft >= 1024) {
+				facingLeft -= 1024;
+			}
+#endif
 			facingLeftCounter += 20;
 		}
 
diff --git a/engines/bladerunner/actor_walk.cpp b/engines/bladerunner/actor_walk.cpp
index 1c91ce0155..536893ce7c 100644
--- a/engines/bladerunner/actor_walk.cpp
+++ b/engines/bladerunner/actor_walk.cpp
@@ -211,6 +211,18 @@ bool ActorWalk::tick(int actorId, float stepDistance, bool mustReachWalkDestinat
 		}
 	}
 
+#if !BLADERUNNER_ORIGINAL_BUGS
+	// safety-guard / validator  check
+	if (_facing >= 1024) {
+		_facing = (_facing % 1024);
+	} else if (_facing < 0) {
+		_facing  = (-1) * _facing;
+		_facing = (_facing % 1024);
+		if (_facing > 0) {
+			_facing  = 1024 - _facing; // this will always be in [1, 1023]
+		}
+	}
+#endif
 	_current.x += stepDistance * _vm->_sinTable1024->at(_facing);
 	_current.z -= stepDistance * _vm->_cosTable1024->at(_facing);
 	_current.y = _vm->_scene->_set->getAltitudeAtXZ(_current.x, _current.z, &walkboxFound);
-- 
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