[Scummvm-git-logs] scummvm master -> b36c487112a01a06fd09d973550ab9458fd9ac72

[athrxx]

This automated email contains information about 1 new commit which have been
pushed to the 'scummvm' repo located at https://github.com/scummvm/scummvm .

Summary:
b36c487112 SCUMM: fix bug no. 14582


Commit: b36c487112a01a06fd09d973550ab9458fd9ac72
    https://github.com/scummvm/scummvm/commit/b36c487112a01a06fd09d973550ab9458fd9ac72
Author: athrxx (athrxx at scummvm.org)
Date: 2023-08-22T20:27:48+02:00

Commit Message:
SCUMM: fix bug no. 14582

(pathfinding doesn't match original)

This does not address the (allegedly) wrong actor turning direction.

Changed paths:
    engines/scumm/actor.cpp


diff --git a/engines/scumm/actor.cpp b/engines/scumm/actor.cpp
index e4b35b53875..5051e767106 100644
--- a/engines/scumm/actor.cpp
+++ b/engines/scumm/actor.cpp
@@ -509,7 +509,13 @@ int Actor::calcMovementFactor(const Common::Point& next) {
 		deltaYFactor = 0;
 	}
 
-	if ((uint)ABS(deltaXFactor >> 16) > _speedx) {
+	// We used to have ABS(deltaXFactor >> 16) for the calculation here, which
+	// caused bug no. https://bugs.scummvm.org/ticket/14582
+	// For SCUMM4-6 it is obvious from disam that they do the division by 0x10000.
+	// SCUMM7/8 original code gives the impression of using deltaXFactor >> 16 at
+	// first glance, but it really doesn't. It is a more complicated operation
+	// which amounts to the exact same thing as the following...
+	if ((uint)ABS(deltaXFactor / 0x10000) > _speedx) {
 		deltaXFactor = _speedx << 16;
 		if (diffX < 0)
 			deltaXFactor = -deltaXFactor;