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-rw-r--r--src/roadveh_cmd.cpp51
1 files changed, 45 insertions, 6 deletions
diff --git a/src/roadveh_cmd.cpp b/src/roadveh_cmd.cpp
index 8eb454f62..3a898373e 100644
--- a/src/roadveh_cmd.cpp
+++ b/src/roadveh_cmd.cpp
@@ -1273,6 +1273,7 @@ static void RoadVehController(Vehicle *v)
if (v->current_order.type == OT_LOADING) return;
if (IsRoadVehInDepot(v)) {
+ /* Vehicle is about to leave a depot */
DiagDirection dir;
const RoadDriveEntry* rdp;
byte rd2;
@@ -1308,6 +1309,7 @@ static void RoadVehController(Vehicle *v)
return;
}
+ /* Check if vehicle needs to proceed, return if it doesn't */
if (!RoadVehAccelerate(v)) return;
if (v->u.road.overtaking != 0) {
@@ -1323,9 +1325,11 @@ static void RoadVehController(Vehicle *v)
}
}
+ /* Save old vehicle position to use at end of move to set viewport area dirty */
BeginVehicleMove(v);
if (v->u.road.state == 255) {
+ /* Vehicle is on a bridge or in a tunnel */
GetNewVehiclePosResult gp;
GetNewVehiclePos(v, &gp);
@@ -1337,7 +1341,7 @@ static void RoadVehController(Vehicle *v)
}
if ((IsTunnelTile(gp.new_tile) || IsBridgeTile(gp.new_tile)) && VehicleEnterTile(v, gp.new_tile, gp.x, gp.y) & 4) {
- //new_dir = RoadGetNewDirection(v, gp.x, gp.y)
+ /* Vehicle has just entered a bridge or tunnel */
v->cur_image = GetRoadVehImage(v, v->direction);
UpdateRoadVehDeltaXY(v);
SetRoadVehPosition(v,gp.x,gp.y);
@@ -1351,10 +1355,11 @@ static void RoadVehController(Vehicle *v)
return;
}
+ /* Get move position data for next frame */
rd = _road_drive_data[(v->u.road.state + (_opt.road_side << 4)) ^ v->u.road.overtaking][v->u.road.frame + 1];
-// switch to another tile
if (rd.x & 0x80) {
+ /* Vehicle is moving to the next tile */
TileIndex tile = v->tile + TileOffsByDiagDir(rd.x & 3);
int dir = RoadFindPathToDest(v, tile, (DiagDirection)(rd.x & 3));
uint32 r;
@@ -1362,6 +1367,7 @@ static void RoadVehController(Vehicle *v)
const RoadDriveEntry *rdp;
if (dir == -1) {
+ /* No path was found to destination */
v->cur_speed = 0;
return;
}
@@ -1372,6 +1378,7 @@ again:
tile = v->tile;
}
+ /* Get position data for first frame on the new tile */
rdp = _road_drive_data[(dir + (_opt.road_side << 4)) ^ v->u.road.overtaking];
x = TileX(tile) * TILE_SIZE + rdp[0].x;
@@ -1382,29 +1389,35 @@ again:
r = VehicleEnterTile(v, tile, x, y);
if (r & 8) {
+ /* Vehicle cannot enter the tile */
if (!IsTileType(tile, MP_TUNNELBRIDGE)) {
v->cur_speed = 0;
return;
}
+ /* Try an about turn to re-enter the previous tile */
dir = _road_reverse_table[rd.x&3];
goto again;
}
if (IS_BYTE_INSIDE(v->u.road.state, 0x20, 0x30) && IsTileType(v->tile, MP_STATION)) {
if ((dir & 7) >= 6) {
+ /* New direction is trying to turn vehicle around.
+ * We can't turn at the exit of a road stop so wait.*/
v->cur_speed = 0;
return;
}
if (IsRoadStop(v->tile)) {
+ /* The tile that the vehicle is leaving is a road stop */
RoadStop *rs = GetRoadStopByTile(v->tile, GetRoadStopType(v->tile));
- // reached a loading bay, mark it as used and clear the usage bit
- SETBIT(rs->status, v->u.road.state & 2 ? 1 : 0); // occupied bay
+ /* Vehicle is leaving a road stop tile, mark bay as free and clear the usage bit */
+ SETBIT(rs->status, v->u.road.state & 2 ? 1 : 0); // set bay as free
CLRBIT(rs->status, 7); // usage bit
}
}
if (!(r & 4)) {
+ /* Set vehicle to first frame on new tile */
v->tile = tile;
v->u.road.state = (byte)dir;
v->u.road.frame = 0;
@@ -1421,6 +1434,7 @@ again:
}
if (rd.x & 0x40) {
+ /* Vehicle has finished turning around, it will now head back onto the same tile */
int dir = RoadFindPathToDest(v, v->tile, (DiagDirection)(rd.x & 3));
uint32 r;
int tmp;
@@ -1428,6 +1442,7 @@ again:
const RoadDriveEntry *rdp;
if (dir == -1) {
+ /* No path was found to destination */
v->cur_speed = 0;
return;
}
@@ -1443,10 +1458,12 @@ again:
r = VehicleEnterTile(v, v->tile, x, y);
if (r & 8) {
+ /* Vehicle cannot enter the tile */
v->cur_speed = 0;
return;
}
+ /* Set vehicle to second frame on the tile */
v->u.road.state = tmp & ~16;
v->u.road.frame = 1;
@@ -1461,15 +1478,19 @@ again:
return;
}
+ /* Calculate new position for the vehicle */
x = (v->x_pos & ~15) + (rd.x & 15);
y = (v->y_pos & ~15) + (rd.y & 15);
new_dir = RoadVehGetSlidingDirection(v, x, y);
if (!IS_BYTE_INSIDE(v->u.road.state, 0x20, 0x30)) {
+ /* Vehicle is not in a road stop.
+ * Check for another vehicle to overtake */
Vehicle* u = RoadVehFindCloseTo(v, x, y, new_dir);
if (u != NULL) {
+ /* There is a vehicle in front overtake it if possible */
if (v->u.road.overtaking == 0) RoadVehCheckOvertake(v, u);
return;
}
@@ -1477,12 +1498,17 @@ again:
old_dir = v->direction;
if (new_dir != old_dir) {
+ /* The vehicle's direction has changed. */
v->direction = new_dir;
v->cur_speed -= (v->cur_speed >> 2);
if (old_dir != v->u.road.state) {
+ /* The vehicle is in a road stop */
v->cur_image = GetRoadVehImage(v, new_dir);
UpdateRoadVehDeltaXY(v);
SetRoadVehPosition(v, v->x_pos, v->y_pos);
+ /* Note, return here means that the frame counter is not incremented
+ * for vehicles changing direction in a road stop. This causes frames to
+ * be repeated. Is this intended? */
return;
}
}
@@ -1492,10 +1518,15 @@ again:
RoadStop *rs = GetRoadStopByTile(v->tile, GetRoadStopType(v->tile));
Station* st = GetStationByTile(v->tile);
+ /* Vehicle is at the stop position (at a bay) in a road stop.
+ * Note, if vehicle is loading/unloading it has already been handled,
+ * so if we get here the vehicle has just arrived or is just ready to leave. */
if (v->current_order.type != OT_LEAVESTATION &&
v->current_order.type != OT_GOTO_DEPOT) {
+ /* Vehicle has arrived at a bay in a road stop */
Order old_order;
+ /* Clear road stop busy bit to allow another vehicle to enter or leave */
CLRBIT(rs->status, 7);
v->last_station_visited = GetStationIndex(v->tile);
@@ -1521,8 +1552,10 @@ again:
return;
}
+ /* Vehicle is ready to leave a bay in a road stop */
if (v->current_order.type != OT_GOTO_DEPOT) {
if (HASBIT(rs->status, 7)) {
+ /* Road stop is busy, so wait */
v->cur_speed = 0;
return;
}
@@ -1530,13 +1563,14 @@ again:
v->current_order.flags = 0;
ClearSlot(v);
}
+ /* Set road stop busy bit to prevent another vehicle trying to enter or leave */
SETBIT(rs->status, 7);
if (rs == v->u.road.slot) {
- //we have arrived at the correct station
+ /* We are leaving the correct station */
ClearSlot(v);
} else if (v->u.road.slot != NULL) {
- //we have arrived at the wrong station
+ /* We are leaving the wrong station */
//XXX The question is .. what to do? Actually we shouldn't be here
//but I guess we need to clear the slot
DEBUG(ms, 0, "Vehicle %d (index %d) arrived at wrong stop", v->unitnumber, v->index);
@@ -1562,12 +1596,17 @@ again:
InvalidateWindowWidget(WC_VEHICLE_VIEW, v->index, STATUS_BAR);
}
+ /* Check tile position conditions - i.e. stop position in depot,
+ * entry onto bridge or into tunnel */
r = VehicleEnterTile(v, v->tile, x, y);
if (r & 8) {
+ /* Vehicle cannot continue */
v->cur_speed = 0;
return;
}
+ /* Move to next frame unless vehicle arrived at a stop position
+ * in a depot or entered a tunnel/bridge */
if ((r & 4) == 0) v->u.road.frame++;
v->cur_image = GetRoadVehImage(v, v->direction);