Make "Go to Transport" button work sensibly.

Droids now go to the nearest transport that they can fit in. Even if they're not
cyborgs. And even if there's a transporter on the other side of the map that they
could go to, instead of going to the one standing right next to them.

src/order.cpp

@@ -2906,19 +2906,31 @@ void orderSelectedStatsTwoLocDir(UDWORD player, DROID_ORDER order, STRUCTURE_STA
 
 
 /** This function runs though all player's droids to check if any of then is a transporter. Returns the transporter droid if any was found, and NULL else.*/
-DROID *FindATransporter(unsigned player)
+DROID *FindATransporter(DROID const *embarkee)
 {
-	DROID *psDroid;
+	bool isCyborg = cyborgDroid(embarkee) || !bMultiPlayer;  // In campaign, any unit can go on a regular transporter, so consider any unit to be a cyborg.
 
-	for (psDroid = apsDroidLists[player]; psDroid != NULL; psDroid = psDroid->psNext)
+	DROID *bestDroid = NULL;
+	unsigned bestDist = ~0u;
+
+	for (DROID *psDroid = apsDroidLists[embarkee->player]; psDroid != NULL; psDroid = psDroid->psNext)
 	{
-		if (psDroid->droidType == DROID_TRANSPORTER || psDroid->droidType == DROID_SUPERTRANSPORTER)
+		if ((isCyborg && psDroid->droidType == DROID_TRANSPORTER) || psDroid->droidType == DROID_SUPERTRANSPORTER)
 		{
-			return psDroid;
+			unsigned dist = iHypot(removeZ(psDroid->pos - embarkee->pos));
+			if (!checkTransporterSpace(psDroid, embarkee, false))
+			{
+				dist += 0x8000000;  // Should prefer transports that aren't full.
+			}
+			if (dist < bestDist)
+			{
+				bestDroid = psDroid;
+				bestDist = dist;
+			}
 		}
 	}
 
-	return NULL;
+	return bestDroid;
 }
 
 
@@ -3293,8 +3305,8 @@ bool secondarySetState(DROID *psDroid, SECONDARY_ORDER sec, SECONDARY_STATE Stat
 					secondarySet = State;
 					break;
 				case DSS_RTL_TRANSPORT:
-					psTransport = FindATransporter(psDroid->player);
-					if (psTransport != NULL && !(bMultiPlayer && !cyborgDroid(psDroid)))
+					psTransport = FindATransporter(psDroid);
+					if (psTransport != NULL)
 					{
 						secondarySet = State;
 					}
@@ -3576,22 +3588,14 @@ bool secondarySetState(DROID *psDroid, SECONDARY_ORDER sec, SECONDARY_STATE Stat
 					CurrState |= DSS_RTL_BASE;
 					break;
 				case DSS_RTL_TRANSPORT:
-					psTransport = FindATransporter(psDroid->player);
+					psTransport = FindATransporter(psDroid);
 					if (psTransport != NULL)
 					{
-						// in multiPlayer can only put cyborgs onto a Transporter
-						if (bMultiPlayer && !cyborgDroid(psDroid))
-						{
-							retVal = false;
-						}
-						else
+						order = DORDER_EMBARK;
+						CurrState |= DSS_RTL_TRANSPORT;
+						if (!orderState(psDroid, DORDER_EMBARK))
 						{
-							order = DORDER_EMBARK;
-							CurrState |= DSS_RTL_TRANSPORT;
-							if (!orderState(psDroid, DORDER_EMBARK))
-							{
-								orderDroidObj(psDroid, DORDER_EMBARK, psTransport, ModeImmediate);
-							}
+							orderDroidObj(psDroid, DORDER_EMBARK, psTransport, ModeImmediate);
 						}
 					}
 					else

src/order.h

@@ -133,7 +133,7 @@ extern void orderGroupMoralCheck(DROID_GROUP *psGroup);
 extern const char* getDroidOrderName(DROID_ORDER order);
 
 /** \brief Gets a player's transporter. */
-extern DROID *FindATransporter(unsigned player);
+DROID *FindATransporter(DROID const *embarkee);
 
 /** \brief Checks if there are any damaged buildings to repair. */
 extern BASE_OBJECT * checkForDamagedStruct(DROID *psDroid, STRUCTURE *psTarget);

src/transporter.cpp

@@ -158,7 +158,7 @@ static bool intAddTransButtonForm(void);
 static bool intAddTransContentsForm(void);
 static bool intAddDroidsAvailForm(void);
 void intRemoveTransContent(void);
-static UDWORD transporterSpaceRequired(DROID *psDroid);
+static UDWORD transporterSpaceRequired(DROID const *psDroid);
 static DROID* transInterfaceDroidList(void);
 static void intTransporterAddDroid(UDWORD id);
 static void intRemoveTransDroidsAvail(void);
@@ -1442,7 +1442,7 @@ void transporterAddDroid(DROID *psTransporter, DROID *psDroidToAdd)
 }
 
 /*check to see if the droid can fit on the Transporter - return true if fits*/
-bool checkTransporterSpace(DROID *psTransporter, DROID *psAssigned)
+bool checkTransporterSpace(DROID const *psTransporter, DROID const *psAssigned, bool mayFlash)
 {
 	DROID		*psDroid, *psNext;
 	UDWORD		capacity;
@@ -1462,8 +1462,8 @@ bool checkTransporterSpace(DROID *psTransporter, DROID *psAssigned)
 	}
 	if (capacity >= transporterSpaceRequired(psAssigned))
 	{
-        //when full flash the transporter button
-        if (capacity - transporterSpaceRequired(psAssigned) == 0)
+		//when full flash the transporter button
+		if (mayFlash && capacity - transporterSpaceRequired(psAssigned) == 0)
         {
             flashMissionButton(IDTRANS_LAUNCH);
         }
@@ -1476,7 +1476,7 @@ bool checkTransporterSpace(DROID *psTransporter, DROID *psAssigned)
 }
 
 /*returns the space the droid occupies on a transporter based on the body size*/
-UDWORD transporterSpaceRequired(DROID *psDroid)
+UDWORD transporterSpaceRequired(DROID const *psDroid)
 {
 	UDWORD	size;
 

src/transporter.h

@@ -48,7 +48,7 @@ extern void intProcessTransporter(UDWORD id);
 extern void transporterAddDroid(DROID *psTransporter, DROID *psDroidToAdd);
 void transporterRemoveDroid(DROID *psTransport, DROID *psDroid, QUEUE_MODE mode);
 /*check to see if the droid can fit on the Transporter - return true if fits*/
-extern bool checkTransporterSpace(DROID *psTransporter, DROID *psAssigned);
+bool checkTransporterSpace(DROID const *psTransporter, DROID const *psAssigned, bool mayFlash = true);
 /*calculates how much space is remaining on the transporter - allows droids to take
 up different amount depending on their body size - currently all are set to one!*/
 extern UDWORD calcRemainingCapacity(DROID *psTransporter);