[Scummvm-cvs-logs] SF.net SVN: scummvm: [28621] scummvm/trunk/engines/parallaction/ callables_ns.cpp

[peres001 at users.sourceforge.net]

Revision: 28621
          http://scummvm.svn.sourceforge.net/scummvm/?rev=28621&view=rev
Author:   peres001
Date:     2007-08-14 12:53:32 -0700 (Tue, 14 Aug 2007)

Log Message:
-----------
Fixed bug (array-overflow) in NS introduction. This randomly caused the intro to crash during sketching.

Modified Paths:
--------------
    scummvm/trunk/engines/parallaction/callables_ns.cpp

Modified: scummvm/trunk/engines/parallaction/callables_ns.cpp
===================================================================
--- scummvm/trunk/engines/parallaction/callables_ns.cpp	2007-08-14 18:58:47 UTC (rev 28620)
+++ scummvm/trunk/engines/parallaction/callables_ns.cpp	2007-08-14 19:53:32 UTC (rev 28621)
@@ -587,7 +587,11 @@
 	//_vm->_gfx->zeroMaskValue(x, y, color);
 
 	BackgroundInfo* info = (BackgroundInfo*)data;
-
+/*
+	if (x < 0 || x > 319 || y < 0 || y > 199) {
+		printf("zeroMask(%i, %i)\n", x, y);
+	}
+*/
 	uint16 _ax = x + y * info->width;
 	info->mask.data[_ax >> 2] &= ~(3 << ((_ax & 3) << 1));
 
@@ -597,12 +601,27 @@
 
 	static uint16 index = 1;
 
-	uint16 newy = _rightHandPositions[2*index+1];
-	uint16 newx = _rightHandPositions[2*index];
+	uint16 newx;
+	uint16 newy;
 
 	uint16 oldy = _rightHandPositions[2*(index-1)+1];
 	uint16 oldx = _rightHandPositions[2*(index-1)];
 
+	// WORKAROUND: original code overflowed _rightHandPositions by trying
+	// to access elements at positions 684 and 685. That used to happen
+	// when index == 342. Code now checks for this possibility and assigns
+	// the last valid value to the new coordinates for drawing without
+	// accessing the array.
+	if (index < 342) {
+		newy = oldy;
+		newx = oldx;
+	} else {
+		newy = _rightHandPositions[2*index+1];
+		newx = _rightHandPositions[2*index];
+	}
+
+	printf("sketch index = %i\n", index);
+
 	Graphics::drawLine(oldx, oldy, newx, newy, 0, zeroMask, _backgroundInfo);
 
 	_rightHandAnim->_left = newx;


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