/// <summary>
/// Initializes a new instance of the <see cref="ContourVertex"/> struct as a copy.
/// </summary>
/// <param name="vert">The original vertex.</param>
/// <param name="region">The region that the vertex belongs to.</param>
public ContourVertex(ContourVertex vert, RegionId region)
{
this.X = vert.X;
this.Y = vert.Y;
this.Z = vert.Z;
this.RegionId = region;
}
/// <summary>
/// Gets the leftness of a triangle formed from 3 contour vertices.
/// </summary>
/// <param name="a">The first vertex.</param>
/// <param name="b">The second vertex.</param>
/// <param name="c">The third vertex.</param>
/// <returns>A value indicating the leftness of the triangle.</returns>
public static bool IsLeft(ref ContourVertex a, ref ContourVertex b, ref ContourVertex c)
{
int area;
Area2D(ref a, ref b, ref c, out area);
return(area < 0);
}
/// <summary>
/// Initializes a new instance of the <see cref="ContourVertex"/> struct as a copy.
/// </summary>
/// <param name="vert">The original vertex.</param>
/// <param name="index">The index of the original vertex, which is temporarily stored in the <see cref="RegionId"/> field.</param>
public ContourVertex(ContourVertex vert, int index)
{
this.X = vert.X;
this.Y = vert.Y;
this.Z = vert.Z;
this.RegionId = new RegionId(index);
}
/// <summary>
/// Initializes a new instance of the <see cref="ContourVertex"/> struct as a copy.
/// </summary>
/// <param name="vert">The original vertex.</param>
/// <param name="index">The index of the original vertex, which is temporarily stored in the <see cref="RegionId"/> field.</param>
public ContourVertex(ContourVertex vert, int index)
{
this.X = vert.X;
this.Y = vert.Y;
this.Z = vert.Z;
this.RegionId = new RegionId(index);
}
/// <summary>
/// Finds the closest indices between two contours. Useful for merging contours.
/// </summary>
/// <param name="a">A contour.</param>
/// <param name="b">Another contour.</param>
/// <param name="indexA">The nearest index on contour A.</param>
/// <param name="indexB">The nearest index on contour B.</param>
private static void GetClosestIndices(Contour a, Contour b, out int indexA, out int indexB)
{
int closestDistance = int.MaxValue;
int lengthA = a.vertices.Length;
int lengthB = b.vertices.Length;
indexA = -1;
indexB = -1;
for (int i = 0; i < lengthA; i++)
{
int vertA = i;
int vertANext = (i + 1) % lengthA;
int vertAPrev = (i + lengthA - 1) % lengthA;
for (int j = 0; j < lengthB; j++)
{
int vertB = j;
//vertB must be infront of vertA
if (ContourVertex.IsLeft(ref a.vertices[vertAPrev], ref a.vertices[vertA], ref b.vertices[vertB]) &&
ContourVertex.IsLeft(ref a.vertices[vertA], ref a.vertices[vertANext], ref b.vertices[vertB]))
{
int dx = b.vertices[vertB].X - a.vertices[vertA].X;
int dz = b.vertices[vertB].Z - a.vertices[vertA].Z;
int tempDist = dx * dx + dz * dz;
if (tempDist < closestDistance)
{
indexA = i;
indexB = j;
closestDistance = tempDist;
}
}
}
}
}
/// <summary>
/// Simplify the contours by reducing the number of edges
/// </summary>
/// <param name="rawVerts">Initial vertices</param>
/// <param name="simplified">New and simplified vertices</param>
/// <param name="maxError">Maximum error allowed</param>
/// <param name="maxEdgeLen">The maximum edge length allowed</param>
/// <param name="buildFlags">Flags determines how to split the long edges</param>
public static void Simplify(List <ContourVertex> rawVerts, List <ContourVertex> simplified, float maxError, int maxEdgeLen, ContourBuildFlags buildFlags)
{
bool tesselateWallEdges = (buildFlags & ContourBuildFlags.TessellateWallEdges) == ContourBuildFlags.TessellateWallEdges;
bool tesselateAreaEdges = (buildFlags & ContourBuildFlags.TessellateAreaEdges) == ContourBuildFlags.TessellateAreaEdges;
//add initial points
bool hasConnections = false;
for (int i = 0; i < rawVerts.Count; i++)
{
if (rawVerts[i].RegionId.Id != 0)
{
hasConnections = true;
break;
}
}
if (hasConnections)
{
//contour has some portals to other regions
//add new point to every location where region changes
for (int i = 0, end = rawVerts.Count; i < end; i++)
{
int ii = (i + 1) % end;
bool differentRegions = rawVerts[i].RegionId.Id != rawVerts[ii].RegionId.Id;
bool areaBorders = RegionId.HasFlags(rawVerts[i].RegionId, RegionFlags.AreaBorder) != RegionId.HasFlags(rawVerts[ii].RegionId, RegionFlags.AreaBorder);
if (differentRegions || areaBorders)
{
simplified.Add(new ContourVertex(rawVerts[i], i));
}
}
}
//add some points if thhere are no connections
if (simplified.Count == 0)
{
//find lower-left and upper-right vertices of contour
int lowerLeftX = rawVerts[0].X;
int lowerLeftY = rawVerts[0].Y;
int lowerLeftZ = rawVerts[0].Z;
RegionId lowerLeftI = RegionId.Null;
int upperRightX = rawVerts[0].X;
int upperRightY = rawVerts[0].Y;
int upperRightZ = rawVerts[0].Z;
RegionId upperRightI = RegionId.Null;
//iterate through points
for (int i = 0; i < rawVerts.Count; i++)
{
int x = rawVerts[i].X;
int y = rawVerts[i].Y;
int z = rawVerts[i].Z;
if (x < lowerLeftX || (x == lowerLeftX && z < lowerLeftZ))
{
lowerLeftX = x;
lowerLeftY = y;
lowerLeftZ = z;
lowerLeftI = new RegionId(i);
}
if (x > upperRightX || (x == upperRightX && z > upperRightZ))
{
upperRightX = x;
upperRightY = y;
upperRightZ = z;
upperRightI = new RegionId(i);
}
}
//save the points
simplified.Add(new ContourVertex(lowerLeftX, lowerLeftY, lowerLeftZ, lowerLeftI));
simplified.Add(new ContourVertex(upperRightX, upperRightY, upperRightZ, upperRightI));
}
//add points until all points are within error tolerance of simplified slope
int numPoints = rawVerts.Count;
for (int i = 0; i < simplified.Count;)
{
int ii = (i + 1) % simplified.Count;
//obtain (x, z) coordinates, along with region id
int ax = simplified[i].X;
int az = simplified[i].Z;
int ai = (int)simplified[i].RegionId;
int bx = simplified[ii].X;
int bz = simplified[ii].Z;
int bi = (int)simplified[ii].RegionId;
float maxDeviation = 0;
int maxi = -1;
int ci, countIncrement, endi;
//traverse segment in lexilogical order (try to go from smallest to largest coordinates?)
if (bx > ax || (bx == ax && bz > az))
{
countIncrement = 1;
ci = (int)(ai + countIncrement) % numPoints;
endi = (int)bi;
}
else
{
countIncrement = numPoints - 1;
ci = (int)(bi + countIncrement) % numPoints;
endi = (int)ai;
}
//tessellate only outer edges or edges between areas
if (rawVerts[ci].RegionId.Id == 0 || RegionId.HasFlags(rawVerts[ci].RegionId, RegionFlags.AreaBorder))
{
//find the maximum deviation
while (ci != endi)
{
float deviation = Distance.PointToSegment2DSquared(rawVerts[ci].X, rawVerts[ci].Z, ax, az, bx, bz);
if (deviation > maxDeviation)
{
maxDeviation = deviation;
maxi = ci;
}
ci = (ci + countIncrement) % numPoints;
}
}
//If max deviation is larger than accepted error, add new point
if (maxi != -1 && maxDeviation > (maxError * maxError))
{
simplified.Insert(i + 1, new ContourVertex(rawVerts[maxi], maxi));
}
else
{
i++;
}
}
//split too long edges
if (maxEdgeLen > 0 && (tesselateAreaEdges || tesselateWallEdges))
{
for (int i = 0; i < simplified.Count;)
{
int ii = (i + 1) % simplified.Count;
//get (x, z) coordinates along with region id
int ax = simplified[i].X;
int az = simplified[i].Z;
int ai = (int)simplified[i].RegionId;
int bx = simplified[ii].X;
int bz = simplified[ii].Z;
int bi = (int)simplified[ii].RegionId;
//find maximum deviation from segment
int maxi = -1;
int ci = (int)(ai + 1) % numPoints;
//tessellate only outer edges or edges between areas
bool tess = false;
//wall edges
if (tesselateWallEdges && rawVerts[ci].RegionId.Id == 0)
{
tess = true;
}
//edges between areas
if (tesselateAreaEdges && RegionId.HasFlags(rawVerts[ci].RegionId, RegionFlags.AreaBorder))
{
tess = true;
}
if (tess)
{
int dx = bx - ax;
int dz = bz - az;
if (dx * dx + dz * dz > maxEdgeLen * maxEdgeLen)
{
//round based on lexilogical direction (smallest to largest cooridinates, first by x.
//if x coordinates are equal, then compare z coordinates)
int n = bi < ai ? (bi + numPoints - ai) : (bi - ai);
if (n > 1)
{
if (bx > ax || (bx == ax && bz > az))
{
maxi = (int)(ai + n / 2) % numPoints;
}
else
{
maxi = (int)(ai + (n + 1) / 2) % numPoints;
}
}
}
}
//add new point
if (maxi != -1)
{
simplified.Insert(i + 1, new ContourVertex(rawVerts[maxi], maxi));
}
else
{
i++;
}
}
}
for (int i = 0; i < simplified.Count; i++)
{
ContourVertex sv = simplified[i];
//take edge vertex flag from current raw point and neighbor region from next raw point
int ai = ((int)sv.RegionId + 1) % numPoints;
RegionId bi = sv.RegionId;
//save new region id
sv.RegionId = RegionId.FromRawBits(((int)rawVerts[ai].RegionId & (RegionId.MaskId | (int)RegionFlags.AreaBorder)) | ((int)rawVerts[(int)bi].RegionId & (int)RegionFlags.VertexBorder));
simplified[i] = sv;
}
}
/// <summary>
/// Gets the 2D area of the triangle ABC.
/// </summary>
/// <param name="a">Point A of triangle ABC.</param>
/// <param name="b">Point B of triangle ABC.</param>
/// <param name="c">Point C of triangle ABC.</param>
/// <param name="area">The 2D area of the triangle.</param>
public static void Area2D(ref ContourVertex a, ref ContourVertex b, ref ContourVertex c, out int area)
{
area = (b.X - a.X) * (c.Z - a.Z) - (c.X - a.X) * (b.Z - a.Z);
}
/// <summary>
/// Initializes a new instance of the <see cref="ContourVertex"/> struct as a copy.
/// </summary>
/// <param name="vert">The original vertex.</param>
/// <param name="region">The region that the vertex belongs to.</param>
public ContourVertex(ContourVertex vert, RegionId region)
{
this.X = vert.X;
this.Y = vert.Y;
this.Z = vert.Z;
this.RegionId = region;
}
/// <summary>
/// Gets the 2D area of the triangle ABC.
/// </summary>
/// <param name="a">Point A of triangle ABC.</param>
/// <param name="b">Point B of triangle ABC.</param>
/// <param name="c">Point C of triangle ABC.</param>
/// <param name="area">The 2D area of the triangle.</param>
public static void Area2D(ref ContourVertex a, ref ContourVertex b, ref ContourVertex c, out int area)
{
area = (b.X - a.X) * (c.Z - a.Z) - (c.X - a.X) * (b.Z - a.Z);
}
/// <summary>
/// Gets the leftness of a triangle formed from 3 contour vertices.
/// </summary>
/// <param name="a">The first vertex.</param>
/// <param name="b">The second vertex.</param>
/// <param name="c">The third vertex.</param>
/// <returns>A value indicating the leftness of the triangle.</returns>
public static bool IsLeft(ref ContourVertex a, ref ContourVertex b, ref ContourVertex c)
{
int area;
Area2D(ref a, ref b, ref c, out area);
return area < 0;
}