Fix desynch on offering an AI an alliance.

Only triggers in the rarely-used 'Allow Alliances' game mode, in games with AIs. When
offering an AI an alliance, the AI would sometimes accept instantly, and the acceptance
was not synchronised.

src/astar.cpp

@@ -295,7 +295,6 @@ static inline void fpathNewNode(PathfindContext &context, PathCoord dest, PathCo
 				// The distance gradient is now known to be somewhere between the direction from A to P and the direction from B to P.
 				static const uint8_t gradYLookup[99] = {140, 140, 140, 140, 140, 140, 140, 140, 140, 140, 140, 140, 139, 139, 139, 139, 139, 139, 139, 139, 139, 138, 138, 138, 138, 138, 138, 137, 137, 137, 137, 137, 136, 136, 136, 136, 135, 135, 135, 134, 134, 134, 134, 133, 133, 133, 132, 132, 132, 131, 131, 130, 130, 130, 129, 129, 128, 128, 127, 127, 126, 126, 126, 125, 125, 124, 123, 123, 122, 122, 121, 121, 120, 119, 119, 118, 118, 117, 116, 116, 115, 114, 113, 113, 112, 111, 110, 110, 109, 108, 107, 106, 106, 105, 104, 103, 102, 101, 100};
 				int gradientY = gradYLookup[gradientX];  // = sqrt(140² -  gradientX²), rounded to nearest integer
-				//int gradientY = iSqrt(70*70 - gradientX*gradientX);  // TODO Faster to use a (small, 50 entries) lookup table?
 				unsigned distP = gradientY*costFactor + distB;
 				node.est -= node.dist - distP;
 				node.dist = distP;
@@ -619,7 +618,7 @@ void fpathSetBlockingMap(PATHJOB *psJob)
 				for (int x = 0; x < mapWidth; ++x)
 			{
 				dangerMap[x + y*mapWidth] = auxTile(x, y, type.owner) & AUXBITS_THREAT;
-				checksumDangerMap ^= map[x + y*mapWidth]*(factor = 3*factor + 1);
+				checksumDangerMap ^= dangerMap[x + y*mapWidth]*(factor = 3*factor + 1);
 			}
 		}
 		syncDebug("blockingMap(%d,%d,%d,%d) = %08X %08X", gameTime, psJob->propulsion, psJob->owner, psJob->moveType, checksumMap, checksumDangerMap);

src/multigifts.cpp

@@ -349,6 +349,7 @@ void requestAlliance(uint8_t from, uint8_t to, bool prop, bool allowAudio)
 		return;  // Wait for our message.
 	}
 
+	syncDebug("Request alliance %d %d", from, to);
 	alliances[from][to] = ALLIANCE_REQUESTED;	// We've asked
 	alliances[to][from] = ALLIANCE_INVITATION;	// They've been invited
 
@@ -397,6 +398,7 @@ void breakAlliance(uint8_t p1, uint8_t p2, bool prop, bool allowAudio)
 		}
 	}
 
+	syncDebug("Break alliance %d %d", p1, p2);
 	alliances[p1][p2] = ALLIANCE_BROKEN;
 	alliances[p2][p1] = ALLIANCE_BROKEN;
 	alliancebits[p1] &= ~(1 << p2);
@@ -421,6 +423,7 @@ void formAlliance(uint8_t p1, uint8_t p2, bool prop, bool allowAudio, bool allow
 		CONPRINTF(ConsoleString,(ConsoleString,_("%s Forms An Alliance With %s"),tm1,getPlayerName(p2)));
 	}
 
+	syncDebug("Form alliance %d %d", p1, p2);
 	alliances[p1][p2] = ALLIANCE_FORMED;
 	alliances[p2][p1] = ALLIANCE_FORMED;
 	if (game.alliance == ALLIANCES_TEAMS)	// this is for shared vision only
@@ -491,19 +494,13 @@ bool recvAlliance(NETQUEUE queue, bool allowAudio)
 		case ALLIANCE_NULL:
 			break;
 		case ALLIANCE_REQUESTED:
-			turnOffMultiMsg(true);
 			requestAlliance(from, to, false, allowAudio);
-			turnOffMultiMsg(false);
 			break;
 		case ALLIANCE_FORMED:
-			turnOffMultiMsg(true);
 			formAlliance(from, to, false, allowAudio, true);
-			turnOffMultiMsg(false);
 			break;
 		case ALLIANCE_BROKEN:
-			turnOffMultiMsg(true);
 			breakAlliance(from, to, false, allowAudio);
-			turnOffMultiMsg(false);
 			break;
 		default:
 			debug(LOG_ERROR, "Unknown alliance state recvd.");