ePathFinderStatus cPath::CalculationStep(cChunk & a_Chunk)
{
m_Chunk = &a_Chunk;
if (m_Status != ePathFinderStatus::CALCULATING)
{
return m_Status;
}
if (m_BadChunkFound)
{
FinishCalculation(ePathFinderStatus::PATH_NOT_FOUND);
return m_Status;
}
if (m_StepsLeft == 0)
{
AttemptToFindAlternative();
}
else
{
--m_StepsLeft;
int i;
for (i = 0; i < CALCULATIONS_PER_STEP; ++i)
{
if (StepOnce()) // StepOnce returns true when no more calculation is needed.
{
break; // if we're here, m_Status must have changed either to PATH_FOUND or PATH_NOT_FOUND.
}
}
m_Chunk = nullptr;
}
return m_Status;
}
bool cPath::StepOnce()
{
cPathCell * CurrentCell = OpenListPop();
// Path not reachable.
if (CurrentCell == nullptr)
{
AttemptToFindAlternative();
return true;
}
// Path found.
if (CurrentCell->m_Location == m_Destination)
{
BuildPath();
FinishCalculation(ePathFinderStatus::PATH_FOUND);
return true;
}
// Calculation not finished yet
// Check if we have a new NearestPoint.
if ((m_Destination - CurrentCell->m_Location).Length() < 5)
{
if (m_Rand.NextInt(4) == 0)
{
m_NearestPointToTarget = CurrentCell;
}
}
else if (CurrentCell->m_H < m_NearestPointToTarget->m_H)
{
m_NearestPointToTarget = CurrentCell;
}
// process a currentCell by inspecting all neighbors.
// Now we start checking adjacent cells.
// If true, no need to do more checks in that direction
bool DoneEast = false,
DoneWest = false,
DoneNorth = false,
DoneSouth = false;
// If true, we can walk in that direction without changing height
// This is used for deciding if to calculate diagonals
bool WalkableEast = false,
WalkableWest = false,
WalkableNorth = false,
WalkableSouth = false;
// If we can jump without hitting the ceiling
if (BodyFitsIn(CurrentCell->m_Location + Vector3i(0, 1, 0), CurrentCell->m_Location))
{
// For ladder climbing
ProcessIfWalkable(CurrentCell->m_Location + Vector3i(0, 1, 0), CurrentCell, JUMP_G_COST);
// Check east-up
if (ProcessIfWalkable(CurrentCell->m_Location + Vector3i(1, 1, 0), CurrentCell, JUMP_G_COST))
{
DoneEast = true;
}
// Check west-up
if (ProcessIfWalkable(CurrentCell->m_Location + Vector3i(-1, 1, 0), CurrentCell, JUMP_G_COST))
{
DoneWest = true;
}
// Check north-up
if (ProcessIfWalkable(CurrentCell->m_Location + Vector3i(0, 1, -1), CurrentCell, JUMP_G_COST))
{
DoneNorth = true;
}
// Check south-up
if (ProcessIfWalkable(CurrentCell->m_Location + Vector3i(0, 1, 1), CurrentCell, JUMP_G_COST))
{
DoneSouth = true;
}
}
// Check North, South, East, West at our own height or below. We are willing to jump up to 3 blocks down.
if (!DoneEast)
{
for (int y = 0; y >= -3; --y)
{
if (ProcessIfWalkable(CurrentCell->m_Location + Vector3i(1, y, 0), CurrentCell, NORMAL_G_COST))
{
DoneEast = true;
if (y == 0)
{
WalkableEast = true;
}
break;
}
}
}
if (!DoneWest)
{
for (int y = 0; y >= -3; --y)
{
if (ProcessIfWalkable(CurrentCell->m_Location + Vector3i(-1, y, 0), CurrentCell, NORMAL_G_COST))
{
DoneWest = true;
if (y == 0)
{
WalkableWest = true;
}
break;
}
}
}
if (!DoneSouth)
{
for (int y = 0; y >= -3; --y)
{
if (ProcessIfWalkable(CurrentCell->m_Location + Vector3i(0, y, 1), CurrentCell, NORMAL_G_COST))
{
DoneWest = true;
if (y == 0)
{
WalkableSouth = true;
}
break;
}
}
}
if (!DoneNorth)
{
for (int y = 0; y >= -3; --y)
{
if (ProcessIfWalkable(CurrentCell->m_Location + Vector3i(0, y, -1), CurrentCell, NORMAL_G_COST))
{
DoneNorth = true;
if (y == 0)
{
WalkableNorth = true;
}
break;
}
}
}
// Check diagonals
if (WalkableNorth && WalkableEast)
{
ProcessIfWalkable(CurrentCell->m_Location + Vector3i(1, 0, -1), CurrentCell, DIAGONAL_G_COST);
}
if (WalkableNorth && WalkableWest)
{
ProcessIfWalkable(CurrentCell->m_Location + Vector3i(-1, 0, -1), CurrentCell, DIAGONAL_G_COST);
}
if (WalkableSouth && WalkableEast)
{
ProcessIfWalkable(CurrentCell->m_Location + Vector3i(1, 0, 1), CurrentCell, DIAGONAL_G_COST);
}
if (WalkableSouth && WalkableWest)
{
ProcessIfWalkable(CurrentCell->m_Location + Vector3i(-1, 0, 1), CurrentCell, DIAGONAL_G_COST);
}
return false;
}
bool cPath::StepOnce()
{
cPathCell * CurrentCell = OpenListPop();
// Path not reachable.
if (CurrentCell == nullptr)
{
AttemptToFindAlternative();
return true;
}
// Path found.
if (CurrentCell->m_Location == m_Destination)
{
BuildPath();
FinishCalculation(ePathFinderStatus::PATH_FOUND);
return true;
}
// Calculation not finished yet.
// Check if we have a new NearestPoint.
// TODO I don't like this that much, there should be a smarter way.
if ((m_Destination - CurrentCell->m_Location).Length() < 5)
{
if (m_Rand.NextInt(4) == 0)
{
m_NearestPointToTarget = CurrentCell;
}
}
else if (CurrentCell->m_H < m_NearestPointToTarget->m_H)
{
m_NearestPointToTarget = CurrentCell;
}
// process a currentCell by inspecting all neighbors.
// Check North, South, East, West on our height.
ProcessIfWalkable(CurrentCell->m_Location + Vector3i(1, 0, 0), CurrentCell, 10);
ProcessIfWalkable(CurrentCell->m_Location + Vector3i(-1, 0, 0), CurrentCell, 10);
ProcessIfWalkable(CurrentCell->m_Location + Vector3i(0, 0, 1), CurrentCell, 10);
ProcessIfWalkable(CurrentCell->m_Location + Vector3i(0, 0, -1), CurrentCell, 10);
// Check diagonals on XY plane.
// x = -1: west, x = 1: east.
for (int x = -1; x <= 1; x += 2)
{
if (GetCell(CurrentCell->m_Location + Vector3i(x, 0, 0))->m_IsSolid) // If there's a solid our east / west.
{
if (!GetCell(CurrentCell->m_Location + Vector3i(0, 1, 0))->m_IsSolid) // If there isn't a solid above.
{
ProcessIfWalkable(CurrentCell->m_Location + Vector3i(x, 1, 0), CurrentCell, JUMP_G_COST); // Check east-up / west-up.
}
}
else
{
ProcessIfWalkable(CurrentCell->m_Location + Vector3i(x, -1, 0), CurrentCell, 14); // Else check east-down / west-down.
}
}
// Check diagonals on the YZ plane.
for (int z = -1; z <= 1; z += 2)
{
if (GetCell(CurrentCell->m_Location + Vector3i(0, 0, z))->m_IsSolid) // If there's a solid our north / south.
{
if (!GetCell(CurrentCell->m_Location + Vector3i(0, 1, 0))->m_IsSolid) // If there isn't a solid above.
{
ProcessIfWalkable(CurrentCell->m_Location + Vector3i(0, 1, z), CurrentCell, JUMP_G_COST); // Check north-up / south-up.
}
}
else
{
ProcessIfWalkable(CurrentCell->m_Location + Vector3i(0, -1, z), CurrentCell, 14); // Else check north-down / south-down.
}
}
// Check diagonals on the XZ plane. (Normal diagonals, this plane is special because of gravity, etc)
for (int x = -1; x <= 1; x += 2)
{
for (int z = -1; z <= 1; z += 2)
{
// This condition prevents diagonal corner cutting.
if (!GetCell(CurrentCell->m_Location + Vector3i(x, 0, 0))->m_IsSolid && !GetCell(CurrentCell->m_Location + Vector3i(0, 0, z))->m_IsSolid)
{
// This prevents falling of "sharp turns" e.g. a 1x1x20 rectangle in the air which breaks in a right angle suddenly.
if (GetCell(CurrentCell->m_Location + Vector3i(x, -1, 0))->m_IsSolid && GetCell(CurrentCell->m_Location + Vector3i(0, -1, z))->m_IsSolid)
{
ProcessIfWalkable(CurrentCell->m_Location + Vector3i(x, 0, z), CurrentCell, 14); // 14 is a good enough approximation of sqrt(10 + 10).
}
}
}
}
return false;
}