191 lines
8.2 KiB
C#

using UnityEngine;
using Unity.Burst;
using Unity.Collections;
using Unity.Jobs;
using Unity.Mathematics;
using Pathfinding.Jobs;
using UnityEngine.Assertions;
namespace Pathfinding.Graphs.Grid.Jobs {
/// <summary>
/// Calculates erosion.
/// Note that to ensure that connections are completely up to date after updating a node you
/// have to calculate the connections for both the changed node and its neighbours.
///
/// In a layered grid graph, this will recalculate the connections for all nodes
/// in the (x,z) cell (it may have multiple layers of nodes).
///
/// See: CalculateConnections(GridNodeBase)
/// </summary>
[BurstCompile]
public struct JobErosion<AdjacencyMapper> : IJob where AdjacencyMapper : GridAdjacencyMapper, new() {
public IntBounds bounds;
public IntBounds writeMask;
public NumNeighbours neighbours;
public int erosion;
public bool erosionUsesTags;
public int erosionStartTag;
[ReadOnly]
public NativeArray<ulong> nodeConnections;
[ReadOnly]
public NativeArray<bool> nodeWalkable;
[WriteOnly]
public NativeArray<bool> outNodeWalkable;
public NativeArray<int> nodeTags;
public int erosionTagsPrecedenceMask;
// Note: the first 3 connections are to nodes with a higher x or z coordinate
// The last 3 connections are to nodes with a lower x or z coordinate
// This is required for the grassfire transform to work properly
// This is a permutation of GridGraph.hexagonNeighbourIndices
static readonly int[] hexagonNeighbourIndices = { 1, 2, 5, 0, 3, 7 };
public void Execute () {
var slice = new Slice3D(bounds, bounds);
var size = slice.slice.size;
slice.AssertMatchesOuter(nodeConnections);
slice.AssertMatchesOuter(nodeWalkable);
slice.AssertMatchesOuter(outNodeWalkable);
slice.AssertMatchesOuter(nodeTags);
Assert.IsTrue(bounds.Contains(writeMask));
var(outerStrideX, outerStrideY, outerStrideZ) = slice.outerStrides;
var(innerStrideX, innerStrideY, innerStrideZ) = slice.innerStrides;
NativeArray<int> neighbourOffsets = new NativeArray<int>(8, Allocator.Temp, NativeArrayOptions.UninitializedMemory);
for (int i = 0; i < 8; i++) neighbourOffsets[i] = GridGraph.neighbourZOffsets[i] * innerStrideZ + GridGraph.neighbourXOffsets[i] * innerStrideX;
var erosionDistances = new NativeArray<int>(slice.length, Allocator.Temp, NativeArrayOptions.ClearMemory);
var adjacencyMapper = new AdjacencyMapper();
var layers = adjacencyMapper.LayerCount(slice.slice);
var outerOffset = slice.outerStartIndex;
if (neighbours == NumNeighbours.Six) {
// Use the grassfire transform: https://en.wikipedia.org/wiki/Grassfire_transform extended to hexagonal graphs
for (int z = 1; z < size.z - 1; z++) {
for (int x = 1; x < size.x - 1; x++) {
for (int y = 0; y < layers; y++) {
// Note: This is significantly faster than using csum, because burst can optimize it better
int outerIndex = z * outerStrideZ + x * outerStrideX + y * outerStrideY + outerOffset;
var innerIndexXZ = z * innerStrideZ + x * innerStrideX;
int innerIndex = innerIndexXZ + y * innerStrideY;
int v = int.MaxValue;
for (int i = 3; i < 6; i++) {
int connection = hexagonNeighbourIndices[i];
if (!adjacencyMapper.HasConnection(outerIndex, connection, nodeConnections)) v = -1;
else v = math.min(v, erosionDistances[adjacencyMapper.GetNeighbourIndex(innerIndexXZ, innerIndex, connection, nodeConnections, neighbourOffsets, innerStrideY)]);
}
erosionDistances[innerIndex] = v + 1;
}
}
}
for (int z = size.z - 2; z > 0; z--) {
for (int x = size.x - 2; x > 0; x--) {
for (int y = 0; y < layers; y++) {
int outerIndex = z * outerStrideZ + x * outerStrideX + y * outerStrideY + outerOffset;
var innerIndexXZ = z * innerStrideZ + x * innerStrideX;
int innerIndex = innerIndexXZ + y * innerStrideY;
int v = int.MaxValue;
for (int i = 3; i < 6; i++) {
int connection = hexagonNeighbourIndices[i];
if (!adjacencyMapper.HasConnection(outerIndex, connection, nodeConnections)) v = -1;
else v = math.min(v, erosionDistances[adjacencyMapper.GetNeighbourIndex(innerIndexXZ, innerIndex, connection, nodeConnections, neighbourOffsets, innerStrideY)]);
}
erosionDistances[innerIndex] = math.min(erosionDistances[innerIndex], v + 1);
}
}
}
} else {
/* Index offset to get neighbour nodes. Added to a node's index to get a neighbour node index.
*
* \code
* Z
* |
* |
*
* 6 2 5
* \ | /
* -- 3 - X - 1 ----- X
* / | \
* 7 0 4
*
* |
* |
* \endcode
*/
const int DirectionDown = 0;
const int DirectionRight = 1;
const int DirectionUp = 2;
const int DirectionLeft = 3;
// Use the grassfire transform: https://en.wikipedia.org/wiki/Grassfire_transform
for (int z = 1; z < size.z - 1; z++) {
for (int x = 1; x < size.x - 1; x++) {
for (int y = 0; y < layers; y++) {
int outerIndex = z * outerStrideZ + x * outerStrideX + y * outerStrideY + outerOffset;
var innerIndexXZ = z * innerStrideZ + x * innerStrideX;
int innerIndex = innerIndexXZ + y * innerStrideY;
var v1 = -1;
if (adjacencyMapper.HasConnection(outerIndex, DirectionDown, nodeConnections)) v1 = erosionDistances[adjacencyMapper.GetNeighbourIndex(innerIndexXZ, innerIndex, DirectionDown, nodeConnections, neighbourOffsets, innerStrideY)];
var v2 = -1;
if (adjacencyMapper.HasConnection(outerIndex, DirectionLeft, nodeConnections)) v2 = erosionDistances[adjacencyMapper.GetNeighbourIndex(innerIndexXZ, innerIndex, DirectionLeft, nodeConnections, neighbourOffsets, innerStrideY)];
erosionDistances[innerIndex] = math.min(v1, v2) + 1;
}
}
}
for (int z = size.z - 2; z > 0; z--) {
for (int x = size.x - 2; x > 0; x--) {
for (int y = 0; y < layers; y++) {
int outerIndex = z * outerStrideZ + x * outerStrideX + y * outerStrideY + outerOffset;
var innerIndexXZ = z * innerStrideZ + x * innerStrideX;
int innerIndex = innerIndexXZ + y * innerStrideY;
var v1 = -1;
if (adjacencyMapper.HasConnection(outerIndex, DirectionUp, nodeConnections)) v1 = erosionDistances[adjacencyMapper.GetNeighbourIndex(innerIndexXZ, innerIndex, DirectionUp, nodeConnections, neighbourOffsets, innerStrideY)];
var v2 = -1;
if (adjacencyMapper.HasConnection(outerIndex, DirectionRight, nodeConnections)) v2 = erosionDistances[adjacencyMapper.GetNeighbourIndex(innerIndexXZ, innerIndex, DirectionRight, nodeConnections, neighbourOffsets, innerStrideY)];
erosionDistances[innerIndex] = math.min(erosionDistances[outerIndex], math.min(v1, v2) + 1);
}
}
}
}
var relativeWriteMask = writeMask.Offset(-bounds.min);
// Erosion tags are allowed to overwrite the ones the user specifies, as well as the ones that are already reserved for erosion.
for (int i = erosionStartTag; i < erosionStartTag + erosion; i++) erosionTagsPrecedenceMask |= 1 << i;
for (int y = relativeWriteMask.min.y; y < relativeWriteMask.max.y; y++) {
for (int z = relativeWriteMask.min.z; z < relativeWriteMask.max.z; z++) {
for (int x = relativeWriteMask.min.x; x < relativeWriteMask.max.x; x++) {
int outerIndex = x * outerStrideX + y * outerStrideY + z * outerStrideZ + outerOffset;
int innerIndex = x * innerStrideX + y * innerStrideY + z * innerStrideZ;
if (erosionUsesTags) {
var prevTag = nodeTags[outerIndex];
outNodeWalkable[outerIndex] = nodeWalkable[outerIndex];
if (erosionDistances[innerIndex] < erosion) {
if (((erosionTagsPrecedenceMask >> prevTag) & 0x1) != 0) {
nodeTags[outerIndex] = nodeWalkable[outerIndex] ? math.min(GraphNode.MaxTagIndex, erosionDistances[innerIndex] + erosionStartTag) : 0;
}
} else if (prevTag >= erosionStartTag && prevTag < erosionStartTag + erosion) {
// If the node already had a tag that was reserved for erosion, but it shouldn't have that tag, then we remove it.
nodeTags[outerIndex] = 0;
}
} else {
outNodeWalkable[outerIndex] = nodeWalkable[outerIndex] & (erosionDistances[innerIndex] >= erosion);
}
}
}
}
}
}
}