SCI: fix kernelCoordinateToPriority

do not check _priorityTop. Sierra never did it (I checked all sorts
of SCI versions, kq4 early, kq5, kq6, etc.) and checking it will
cause at least a priority issue in lsl2 in room 54 (airplane that
is taking off will be drawn using priority 1 instead of 0)

1 files changed, 4 insertions, 2 deletions

diff --git a/engines/sci/graphics/ports.cpp b/engines/sci/graphics/ports.cpp
index bcc991081e..0d00ce01e6 100644
--- a/engines/sci/graphics/ports.cpp
+++ b/engines/sci/graphics/ports.cpp
@@ -717,8 +717,10 @@ void GfxPorts::kernelGraphAdjustPriority(int top, int bottom) {
 }
 
 byte GfxPorts::kernelCoordinateToPriority(int16 y) {
-	if (y < _priorityTop)
-		return _priorityBands[_priorityTop];
+	if (y < 0) // Sierra did not check this, we do for safety reasons
+		return _priorityBands[0];
+	// do NOT check for _priorityTop in here. Sierra never did that and it would cause
+	// at least priority issues in room 54 of lsl2 (airplane)
 	if (y > _priorityBottom)
 		return _priorityBands[_priorityBottom];
 	return _priorityBands[y];