virtualx-engine/thirdparty/recastnavigation/Recast/Source/RecastContour.cpp
2017-09-04 21:41:57 +01:00

1105 lines
30 KiB
C++

//
// Copyright (c) 2009-2010 Mikko Mononen memon@inside.org
//
// This software is provided 'as-is', without any express or implied
// warranty. In no event will the authors be held liable for any damages
// arising from the use of this software.
// Permission is granted to anyone to use this software for any purpose,
// including commercial applications, and to alter it and redistribute it
// freely, subject to the following restrictions:
// 1. The origin of this software must not be misrepresented; you must not
// claim that you wrote the original software. If you use this software
// in a product, an acknowledgment in the product documentation would be
// appreciated but is not required.
// 2. Altered source versions must be plainly marked as such, and must not be
// misrepresented as being the original software.
// 3. This notice may not be removed or altered from any source distribution.
//
#define _USE_MATH_DEFINES
#include <math.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include "Recast.h"
#include "RecastAlloc.h"
#include "RecastAssert.h"
static int getCornerHeight(int x, int y, int i, int dir,
const rcCompactHeightfield& chf,
bool& isBorderVertex)
{
const rcCompactSpan& s = chf.spans[i];
int ch = (int)s.y;
int dirp = (dir+1) & 0x3;
unsigned int regs[4] = {0,0,0,0};
// Combine region and area codes in order to prevent
// border vertices which are in between two areas to be removed.
regs[0] = chf.spans[i].reg | (chf.areas[i] << 16);
if (rcGetCon(s, dir) != RC_NOT_CONNECTED)
{
const int ax = x + rcGetDirOffsetX(dir);
const int ay = y + rcGetDirOffsetY(dir);
const int ai = (int)chf.cells[ax+ay*chf.width].index + rcGetCon(s, dir);
const rcCompactSpan& as = chf.spans[ai];
ch = rcMax(ch, (int)as.y);
regs[1] = chf.spans[ai].reg | (chf.areas[ai] << 16);
if (rcGetCon(as, dirp) != RC_NOT_CONNECTED)
{
const int ax2 = ax + rcGetDirOffsetX(dirp);
const int ay2 = ay + rcGetDirOffsetY(dirp);
const int ai2 = (int)chf.cells[ax2+ay2*chf.width].index + rcGetCon(as, dirp);
const rcCompactSpan& as2 = chf.spans[ai2];
ch = rcMax(ch, (int)as2.y);
regs[2] = chf.spans[ai2].reg | (chf.areas[ai2] << 16);
}
}
if (rcGetCon(s, dirp) != RC_NOT_CONNECTED)
{
const int ax = x + rcGetDirOffsetX(dirp);
const int ay = y + rcGetDirOffsetY(dirp);
const int ai = (int)chf.cells[ax+ay*chf.width].index + rcGetCon(s, dirp);
const rcCompactSpan& as = chf.spans[ai];
ch = rcMax(ch, (int)as.y);
regs[3] = chf.spans[ai].reg | (chf.areas[ai] << 16);
if (rcGetCon(as, dir) != RC_NOT_CONNECTED)
{
const int ax2 = ax + rcGetDirOffsetX(dir);
const int ay2 = ay + rcGetDirOffsetY(dir);
const int ai2 = (int)chf.cells[ax2+ay2*chf.width].index + rcGetCon(as, dir);
const rcCompactSpan& as2 = chf.spans[ai2];
ch = rcMax(ch, (int)as2.y);
regs[2] = chf.spans[ai2].reg | (chf.areas[ai2] << 16);
}
}
// Check if the vertex is special edge vertex, these vertices will be removed later.
for (int j = 0; j < 4; ++j)
{
const int a = j;
const int b = (j+1) & 0x3;
const int c = (j+2) & 0x3;
const int d = (j+3) & 0x3;
// The vertex is a border vertex there are two same exterior cells in a row,
// followed by two interior cells and none of the regions are out of bounds.
const bool twoSameExts = (regs[a] & regs[b] & RC_BORDER_REG) != 0 && regs[a] == regs[b];
const bool twoInts = ((regs[c] | regs[d]) & RC_BORDER_REG) == 0;
const bool intsSameArea = (regs[c]>>16) == (regs[d]>>16);
const bool noZeros = regs[a] != 0 && regs[b] != 0 && regs[c] != 0 && regs[d] != 0;
if (twoSameExts && twoInts && intsSameArea && noZeros)
{
isBorderVertex = true;
break;
}
}
return ch;
}
static void walkContour(int x, int y, int i,
rcCompactHeightfield& chf,
unsigned char* flags, rcIntArray& points)
{
// Choose the first non-connected edge
unsigned char dir = 0;
while ((flags[i] & (1 << dir)) == 0)
dir++;
unsigned char startDir = dir;
int starti = i;
const unsigned char area = chf.areas[i];
int iter = 0;
while (++iter < 40000)
{
if (flags[i] & (1 << dir))
{
// Choose the edge corner
bool isBorderVertex = false;
bool isAreaBorder = false;
int px = x;
int py = getCornerHeight(x, y, i, dir, chf, isBorderVertex);
int pz = y;
switch(dir)
{
case 0: pz++; break;
case 1: px++; pz++; break;
case 2: px++; break;
}
int r = 0;
const rcCompactSpan& s = chf.spans[i];
if (rcGetCon(s, dir) != RC_NOT_CONNECTED)
{
const int ax = x + rcGetDirOffsetX(dir);
const int ay = y + rcGetDirOffsetY(dir);
const int ai = (int)chf.cells[ax+ay*chf.width].index + rcGetCon(s, dir);
r = (int)chf.spans[ai].reg;
if (area != chf.areas[ai])
isAreaBorder = true;
}
if (isBorderVertex)
r |= RC_BORDER_VERTEX;
if (isAreaBorder)
r |= RC_AREA_BORDER;
points.push(px);
points.push(py);
points.push(pz);
points.push(r);
flags[i] &= ~(1 << dir); // Remove visited edges
dir = (dir+1) & 0x3; // Rotate CW
}
else
{
int ni = -1;
const int nx = x + rcGetDirOffsetX(dir);
const int ny = y + rcGetDirOffsetY(dir);
const rcCompactSpan& s = chf.spans[i];
if (rcGetCon(s, dir) != RC_NOT_CONNECTED)
{
const rcCompactCell& nc = chf.cells[nx+ny*chf.width];
ni = (int)nc.index + rcGetCon(s, dir);
}
if (ni == -1)
{
// Should not happen.
return;
}
x = nx;
y = ny;
i = ni;
dir = (dir+3) & 0x3; // Rotate CCW
}
if (starti == i && startDir == dir)
{
break;
}
}
}
static float distancePtSeg(const int x, const int z,
const int px, const int pz,
const int qx, const int qz)
{
float pqx = (float)(qx - px);
float pqz = (float)(qz - pz);
float dx = (float)(x - px);
float dz = (float)(z - pz);
float d = pqx*pqx + pqz*pqz;
float t = pqx*dx + pqz*dz;
if (d > 0)
t /= d;
if (t < 0)
t = 0;
else if (t > 1)
t = 1;
dx = px + t*pqx - x;
dz = pz + t*pqz - z;
return dx*dx + dz*dz;
}
static void simplifyContour(rcIntArray& points, rcIntArray& simplified,
const float maxError, const int maxEdgeLen, const int buildFlags)
{
// Add initial points.
bool hasConnections = false;
for (int i = 0; i < points.size(); i += 4)
{
if ((points[i+3] & RC_CONTOUR_REG_MASK) != 0)
{
hasConnections = true;
break;
}
}
if (hasConnections)
{
// The contour has some portals to other regions.
// Add a new point to every location where the region changes.
for (int i = 0, ni = points.size()/4; i < ni; ++i)
{
int ii = (i+1) % ni;
const bool differentRegs = (points[i*4+3] & RC_CONTOUR_REG_MASK) != (points[ii*4+3] & RC_CONTOUR_REG_MASK);
const bool areaBorders = (points[i*4+3] & RC_AREA_BORDER) != (points[ii*4+3] & RC_AREA_BORDER);
if (differentRegs || areaBorders)
{
simplified.push(points[i*4+0]);
simplified.push(points[i*4+1]);
simplified.push(points[i*4+2]);
simplified.push(i);
}
}
}
if (simplified.size() == 0)
{
// If there is no connections at all,
// create some initial points for the simplification process.
// Find lower-left and upper-right vertices of the contour.
int llx = points[0];
int lly = points[1];
int llz = points[2];
int lli = 0;
int urx = points[0];
int ury = points[1];
int urz = points[2];
int uri = 0;
for (int i = 0; i < points.size(); i += 4)
{
int x = points[i+0];
int y = points[i+1];
int z = points[i+2];
if (x < llx || (x == llx && z < llz))
{
llx = x;
lly = y;
llz = z;
lli = i/4;
}
if (x > urx || (x == urx && z > urz))
{
urx = x;
ury = y;
urz = z;
uri = i/4;
}
}
simplified.push(llx);
simplified.push(lly);
simplified.push(llz);
simplified.push(lli);
simplified.push(urx);
simplified.push(ury);
simplified.push(urz);
simplified.push(uri);
}
// Add points until all raw points are within
// error tolerance to the simplified shape.
const int pn = points.size()/4;
for (int i = 0; i < simplified.size()/4; )
{
int ii = (i+1) % (simplified.size()/4);
int ax = simplified[i*4+0];
int az = simplified[i*4+2];
int ai = simplified[i*4+3];
int bx = simplified[ii*4+0];
int bz = simplified[ii*4+2];
int bi = simplified[ii*4+3];
// Find maximum deviation from the segment.
float maxd = 0;
int maxi = -1;
int ci, cinc, endi;
// Traverse the segment in lexilogical order so that the
// max deviation is calculated similarly when traversing
// opposite segments.
if (bx > ax || (bx == ax && bz > az))
{
cinc = 1;
ci = (ai+cinc) % pn;
endi = bi;
}
else
{
cinc = pn-1;
ci = (bi+cinc) % pn;
endi = ai;
rcSwap(ax, bx);
rcSwap(az, bz);
}
// Tessellate only outer edges or edges between areas.
if ((points[ci*4+3] & RC_CONTOUR_REG_MASK) == 0 ||
(points[ci*4+3] & RC_AREA_BORDER))
{
while (ci != endi)
{
float d = distancePtSeg(points[ci*4+0], points[ci*4+2], ax, az, bx, bz);
if (d > maxd)
{
maxd = d;
maxi = ci;
}
ci = (ci+cinc) % pn;
}
}
// If the max deviation is larger than accepted error,
// add new point, else continue to next segment.
if (maxi != -1 && maxd > (maxError*maxError))
{
// Add space for the new point.
simplified.resize(simplified.size()+4);
const int n = simplified.size()/4;
for (int j = n-1; j > i; --j)
{
simplified[j*4+0] = simplified[(j-1)*4+0];
simplified[j*4+1] = simplified[(j-1)*4+1];
simplified[j*4+2] = simplified[(j-1)*4+2];
simplified[j*4+3] = simplified[(j-1)*4+3];
}
// Add the point.
simplified[(i+1)*4+0] = points[maxi*4+0];
simplified[(i+1)*4+1] = points[maxi*4+1];
simplified[(i+1)*4+2] = points[maxi*4+2];
simplified[(i+1)*4+3] = maxi;
}
else
{
++i;
}
}
// Split too long edges.
if (maxEdgeLen > 0 && (buildFlags & (RC_CONTOUR_TESS_WALL_EDGES|RC_CONTOUR_TESS_AREA_EDGES)) != 0)
{
for (int i = 0; i < simplified.size()/4; )
{
const int ii = (i+1) % (simplified.size()/4);
const int ax = simplified[i*4+0];
const int az = simplified[i*4+2];
const int ai = simplified[i*4+3];
const int bx = simplified[ii*4+0];
const int bz = simplified[ii*4+2];
const int bi = simplified[ii*4+3];
// Find maximum deviation from the segment.
int maxi = -1;
int ci = (ai+1) % pn;
// Tessellate only outer edges or edges between areas.
bool tess = false;
// Wall edges.
if ((buildFlags & RC_CONTOUR_TESS_WALL_EDGES) && (points[ci*4+3] & RC_CONTOUR_REG_MASK) == 0)
tess = true;
// Edges between areas.
if ((buildFlags & RC_CONTOUR_TESS_AREA_EDGES) && (points[ci*4+3] & RC_AREA_BORDER))
tess = true;
if (tess)
{
int dx = bx - ax;
int dz = bz - az;
if (dx*dx + dz*dz > maxEdgeLen*maxEdgeLen)
{
// Round based on the segments in lexilogical order so that the
// max tesselation is consistent regardles in which direction
// segments are traversed.
const int n = bi < ai ? (bi+pn - ai) : (bi - ai);
if (n > 1)
{
if (bx > ax || (bx == ax && bz > az))
maxi = (ai + n/2) % pn;
else
maxi = (ai + (n+1)/2) % pn;
}
}
}
// If the max deviation is larger than accepted error,
// add new point, else continue to next segment.
if (maxi != -1)
{
// Add space for the new point.
simplified.resize(simplified.size()+4);
const int n = simplified.size()/4;
for (int j = n-1; j > i; --j)
{
simplified[j*4+0] = simplified[(j-1)*4+0];
simplified[j*4+1] = simplified[(j-1)*4+1];
simplified[j*4+2] = simplified[(j-1)*4+2];
simplified[j*4+3] = simplified[(j-1)*4+3];
}
// Add the point.
simplified[(i+1)*4+0] = points[maxi*4+0];
simplified[(i+1)*4+1] = points[maxi*4+1];
simplified[(i+1)*4+2] = points[maxi*4+2];
simplified[(i+1)*4+3] = maxi;
}
else
{
++i;
}
}
}
for (int i = 0; i < simplified.size()/4; ++i)
{
// The edge vertex flag is take from the current raw point,
// and the neighbour region is take from the next raw point.
const int ai = (simplified[i*4+3]+1) % pn;
const int bi = simplified[i*4+3];
simplified[i*4+3] = (points[ai*4+3] & (RC_CONTOUR_REG_MASK|RC_AREA_BORDER)) | (points[bi*4+3] & RC_BORDER_VERTEX);
}
}
static int calcAreaOfPolygon2D(const int* verts, const int nverts)
{
int area = 0;
for (int i = 0, j = nverts-1; i < nverts; j=i++)
{
const int* vi = &verts[i*4];
const int* vj = &verts[j*4];
area += vi[0] * vj[2] - vj[0] * vi[2];
}
return (area+1) / 2;
}
// TODO: these are the same as in RecastMesh.cpp, consider using the same.
// Last time I checked the if version got compiled using cmov, which was a lot faster than module (with idiv).
inline int prev(int i, int n) { return i-1 >= 0 ? i-1 : n-1; }
inline int next(int i, int n) { return i+1 < n ? i+1 : 0; }
inline int area2(const int* a, const int* b, const int* c)
{
return (b[0] - a[0]) * (c[2] - a[2]) - (c[0] - a[0]) * (b[2] - a[2]);
}
// Exclusive or: true iff exactly one argument is true.
// The arguments are negated to ensure that they are 0/1
// values. Then the bitwise Xor operator may apply.
// (This idea is due to Michael Baldwin.)
inline bool xorb(bool x, bool y)
{
return !x ^ !y;
}
// Returns true iff c is strictly to the left of the directed
// line through a to b.
inline bool left(const int* a, const int* b, const int* c)
{
return area2(a, b, c) < 0;
}
inline bool leftOn(const int* a, const int* b, const int* c)
{
return area2(a, b, c) <= 0;
}
inline bool collinear(const int* a, const int* b, const int* c)
{
return area2(a, b, c) == 0;
}
// Returns true iff ab properly intersects cd: they share
// a point interior to both segments. The properness of the
// intersection is ensured by using strict leftness.
static bool intersectProp(const int* a, const int* b, const int* c, const int* d)
{
// Eliminate improper cases.
if (collinear(a,b,c) || collinear(a,b,d) ||
collinear(c,d,a) || collinear(c,d,b))
return false;
return xorb(left(a,b,c), left(a,b,d)) && xorb(left(c,d,a), left(c,d,b));
}
// Returns T iff (a,b,c) are collinear and point c lies
// on the closed segement ab.
static bool between(const int* a, const int* b, const int* c)
{
if (!collinear(a, b, c))
return false;
// If ab not vertical, check betweenness on x; else on y.
if (a[0] != b[0])
return ((a[0] <= c[0]) && (c[0] <= b[0])) || ((a[0] >= c[0]) && (c[0] >= b[0]));
else
return ((a[2] <= c[2]) && (c[2] <= b[2])) || ((a[2] >= c[2]) && (c[2] >= b[2]));
}
// Returns true iff segments ab and cd intersect, properly or improperly.
static bool intersect(const int* a, const int* b, const int* c, const int* d)
{
if (intersectProp(a, b, c, d))
return true;
else if (between(a, b, c) || between(a, b, d) ||
between(c, d, a) || between(c, d, b))
return true;
else
return false;
}
static bool vequal(const int* a, const int* b)
{
return a[0] == b[0] && a[2] == b[2];
}
static bool intersectSegCountour(const int* d0, const int* d1, int i, int n, const int* verts)
{
// For each edge (k,k+1) of P
for (int k = 0; k < n; k++)
{
int k1 = next(k, n);
// Skip edges incident to i.
if (i == k || i == k1)
continue;
const int* p0 = &verts[k * 4];
const int* p1 = &verts[k1 * 4];
if (vequal(d0, p0) || vequal(d1, p0) || vequal(d0, p1) || vequal(d1, p1))
continue;
if (intersect(d0, d1, p0, p1))
return true;
}
return false;
}
static bool inCone(int i, int n, const int* verts, const int* pj)
{
const int* pi = &verts[i * 4];
const int* pi1 = &verts[next(i, n) * 4];
const int* pin1 = &verts[prev(i, n) * 4];
// If P[i] is a convex vertex [ i+1 left or on (i-1,i) ].
if (leftOn(pin1, pi, pi1))
return left(pi, pj, pin1) && left(pj, pi, pi1);
// Assume (i-1,i,i+1) not collinear.
// else P[i] is reflex.
return !(leftOn(pi, pj, pi1) && leftOn(pj, pi, pin1));
}
static void removeDegenerateSegments(rcIntArray& simplified)
{
// Remove adjacent vertices which are equal on xz-plane,
// or else the triangulator will get confused.
int npts = simplified.size()/4;
for (int i = 0; i < npts; ++i)
{
int ni = next(i, npts);
if (vequal(&simplified[i*4], &simplified[ni*4]))
{
// Degenerate segment, remove.
for (int j = i; j < simplified.size()/4-1; ++j)
{
simplified[j*4+0] = simplified[(j+1)*4+0];
simplified[j*4+1] = simplified[(j+1)*4+1];
simplified[j*4+2] = simplified[(j+1)*4+2];
simplified[j*4+3] = simplified[(j+1)*4+3];
}
simplified.resize(simplified.size()-4);
npts--;
}
}
}
static bool mergeContours(rcContour& ca, rcContour& cb, int ia, int ib)
{
const int maxVerts = ca.nverts + cb.nverts + 2;
int* verts = (int*)rcAlloc(sizeof(int)*maxVerts*4, RC_ALLOC_PERM);
if (!verts)
return false;
int nv = 0;
// Copy contour A.
for (int i = 0; i <= ca.nverts; ++i)
{
int* dst = &verts[nv*4];
const int* src = &ca.verts[((ia+i)%ca.nverts)*4];
dst[0] = src[0];
dst[1] = src[1];
dst[2] = src[2];
dst[3] = src[3];
nv++;
}
// Copy contour B
for (int i = 0; i <= cb.nverts; ++i)
{
int* dst = &verts[nv*4];
const int* src = &cb.verts[((ib+i)%cb.nverts)*4];
dst[0] = src[0];
dst[1] = src[1];
dst[2] = src[2];
dst[3] = src[3];
nv++;
}
rcFree(ca.verts);
ca.verts = verts;
ca.nverts = nv;
rcFree(cb.verts);
cb.verts = 0;
cb.nverts = 0;
return true;
}
struct rcContourHole
{
rcContour* contour;
int minx, minz, leftmost;
};
struct rcContourRegion
{
rcContour* outline;
rcContourHole* holes;
int nholes;
};
struct rcPotentialDiagonal
{
int vert;
int dist;
};
// Finds the lowest leftmost vertex of a contour.
static void findLeftMostVertex(rcContour* contour, int* minx, int* minz, int* leftmost)
{
*minx = contour->verts[0];
*minz = contour->verts[2];
*leftmost = 0;
for (int i = 1; i < contour->nverts; i++)
{
const int x = contour->verts[i*4+0];
const int z = contour->verts[i*4+2];
if (x < *minx || (x == *minx && z < *minz))
{
*minx = x;
*minz = z;
*leftmost = i;
}
}
}
static int compareHoles(const void* va, const void* vb)
{
const rcContourHole* a = (const rcContourHole*)va;
const rcContourHole* b = (const rcContourHole*)vb;
if (a->minx == b->minx)
{
if (a->minz < b->minz)
return -1;
if (a->minz > b->minz)
return 1;
}
else
{
if (a->minx < b->minx)
return -1;
if (a->minx > b->minx)
return 1;
}
return 0;
}
static int compareDiagDist(const void* va, const void* vb)
{
const rcPotentialDiagonal* a = (const rcPotentialDiagonal*)va;
const rcPotentialDiagonal* b = (const rcPotentialDiagonal*)vb;
if (a->dist < b->dist)
return -1;
if (a->dist > b->dist)
return 1;
return 0;
}
static void mergeRegionHoles(rcContext* ctx, rcContourRegion& region)
{
// Sort holes from left to right.
for (int i = 0; i < region.nholes; i++)
findLeftMostVertex(region.holes[i].contour, &region.holes[i].minx, &region.holes[i].minz, &region.holes[i].leftmost);
qsort(region.holes, region.nholes, sizeof(rcContourHole), compareHoles);
int maxVerts = region.outline->nverts;
for (int i = 0; i < region.nholes; i++)
maxVerts += region.holes[i].contour->nverts;
rcScopedDelete<rcPotentialDiagonal> diags((rcPotentialDiagonal*)rcAlloc(sizeof(rcPotentialDiagonal)*maxVerts, RC_ALLOC_TEMP));
if (!diags)
{
ctx->log(RC_LOG_WARNING, "mergeRegionHoles: Failed to allocated diags %d.", maxVerts);
return;
}
rcContour* outline = region.outline;
// Merge holes into the outline one by one.
for (int i = 0; i < region.nholes; i++)
{
rcContour* hole = region.holes[i].contour;
int index = -1;
int bestVertex = region.holes[i].leftmost;
for (int iter = 0; iter < hole->nverts; iter++)
{
// Find potential diagonals.
// The 'best' vertex must be in the cone described by 3 cosequtive vertices of the outline.
// ..o j-1
// |
// | * best
// |
// j o-----o j+1
// :
int ndiags = 0;
const int* corner = &hole->verts[bestVertex*4];
for (int j = 0; j < outline->nverts; j++)
{
if (inCone(j, outline->nverts, outline->verts, corner))
{
int dx = outline->verts[j*4+0] - corner[0];
int dz = outline->verts[j*4+2] - corner[2];
diags[ndiags].vert = j;
diags[ndiags].dist = dx*dx + dz*dz;
ndiags++;
}
}
// Sort potential diagonals by distance, we want to make the connection as short as possible.
qsort(diags, ndiags, sizeof(rcPotentialDiagonal), compareDiagDist);
// Find a diagonal that is not intersecting the outline not the remaining holes.
index = -1;
for (int j = 0; j < ndiags; j++)
{
const int* pt = &outline->verts[diags[j].vert*4];
bool intersect = intersectSegCountour(pt, corner, diags[i].vert, outline->nverts, outline->verts);
for (int k = i; k < region.nholes && !intersect; k++)
intersect |= intersectSegCountour(pt, corner, -1, region.holes[k].contour->nverts, region.holes[k].contour->verts);
if (!intersect)
{
index = diags[j].vert;
break;
}
}
// If found non-intersecting diagonal, stop looking.
if (index != -1)
break;
// All the potential diagonals for the current vertex were intersecting, try next vertex.
bestVertex = (bestVertex + 1) % hole->nverts;
}
if (index == -1)
{
ctx->log(RC_LOG_WARNING, "mergeHoles: Failed to find merge points for %p and %p.", region.outline, hole);
continue;
}
if (!mergeContours(*region.outline, *hole, index, bestVertex))
{
ctx->log(RC_LOG_WARNING, "mergeHoles: Failed to merge contours %p and %p.", region.outline, hole);
continue;
}
}
}
/// @par
///
/// The raw contours will match the region outlines exactly. The @p maxError and @p maxEdgeLen
/// parameters control how closely the simplified contours will match the raw contours.
///
/// Simplified contours are generated such that the vertices for portals between areas match up.
/// (They are considered mandatory vertices.)
///
/// Setting @p maxEdgeLength to zero will disabled the edge length feature.
///
/// See the #rcConfig documentation for more information on the configuration parameters.
///
/// @see rcAllocContourSet, rcCompactHeightfield, rcContourSet, rcConfig
bool rcBuildContours(rcContext* ctx, rcCompactHeightfield& chf,
const float maxError, const int maxEdgeLen,
rcContourSet& cset, const int buildFlags)
{
rcAssert(ctx);
const int w = chf.width;
const int h = chf.height;
const int borderSize = chf.borderSize;
rcScopedTimer timer(ctx, RC_TIMER_BUILD_CONTOURS);
rcVcopy(cset.bmin, chf.bmin);
rcVcopy(cset.bmax, chf.bmax);
if (borderSize > 0)
{
// If the heightfield was build with bordersize, remove the offset.
const float pad = borderSize*chf.cs;
cset.bmin[0] += pad;
cset.bmin[2] += pad;
cset.bmax[0] -= pad;
cset.bmax[2] -= pad;
}
cset.cs = chf.cs;
cset.ch = chf.ch;
cset.width = chf.width - chf.borderSize*2;
cset.height = chf.height - chf.borderSize*2;
cset.borderSize = chf.borderSize;
cset.maxError = maxError;
int maxContours = rcMax((int)chf.maxRegions, 8);
cset.conts = (rcContour*)rcAlloc(sizeof(rcContour)*maxContours, RC_ALLOC_PERM);
if (!cset.conts)
return false;
cset.nconts = 0;
rcScopedDelete<unsigned char> flags((unsigned char*)rcAlloc(sizeof(unsigned char)*chf.spanCount, RC_ALLOC_TEMP));
if (!flags)
{
ctx->log(RC_LOG_ERROR, "rcBuildContours: Out of memory 'flags' (%d).", chf.spanCount);
return false;
}
ctx->startTimer(RC_TIMER_BUILD_CONTOURS_TRACE);
// Mark boundaries.
for (int y = 0; y < h; ++y)
{
for (int x = 0; x < w; ++x)
{
const rcCompactCell& c = chf.cells[x+y*w];
for (int i = (int)c.index, ni = (int)(c.index+c.count); i < ni; ++i)
{
unsigned char res = 0;
const rcCompactSpan& s = chf.spans[i];
if (!chf.spans[i].reg || (chf.spans[i].reg & RC_BORDER_REG))
{
flags[i] = 0;
continue;
}
for (int dir = 0; dir < 4; ++dir)
{
unsigned short r = 0;
if (rcGetCon(s, dir) != RC_NOT_CONNECTED)
{
const int ax = x + rcGetDirOffsetX(dir);
const int ay = y + rcGetDirOffsetY(dir);
const int ai = (int)chf.cells[ax+ay*w].index + rcGetCon(s, dir);
r = chf.spans[ai].reg;
}
if (r == chf.spans[i].reg)
res |= (1 << dir);
}
flags[i] = res ^ 0xf; // Inverse, mark non connected edges.
}
}
}
ctx->stopTimer(RC_TIMER_BUILD_CONTOURS_TRACE);
rcIntArray verts(256);
rcIntArray simplified(64);
for (int y = 0; y < h; ++y)
{
for (int x = 0; x < w; ++x)
{
const rcCompactCell& c = chf.cells[x+y*w];
for (int i = (int)c.index, ni = (int)(c.index+c.count); i < ni; ++i)
{
if (flags[i] == 0 || flags[i] == 0xf)
{
flags[i] = 0;
continue;
}
const unsigned short reg = chf.spans[i].reg;
if (!reg || (reg & RC_BORDER_REG))
continue;
const unsigned char area = chf.areas[i];
verts.resize(0);
simplified.resize(0);
ctx->startTimer(RC_TIMER_BUILD_CONTOURS_TRACE);
walkContour(x, y, i, chf, flags, verts);
ctx->stopTimer(RC_TIMER_BUILD_CONTOURS_TRACE);
ctx->startTimer(RC_TIMER_BUILD_CONTOURS_SIMPLIFY);
simplifyContour(verts, simplified, maxError, maxEdgeLen, buildFlags);
removeDegenerateSegments(simplified);
ctx->stopTimer(RC_TIMER_BUILD_CONTOURS_SIMPLIFY);
// Store region->contour remap info.
// Create contour.
if (simplified.size()/4 >= 3)
{
if (cset.nconts >= maxContours)
{
// Allocate more contours.
// This happens when a region has holes.
const int oldMax = maxContours;
maxContours *= 2;
rcContour* newConts = (rcContour*)rcAlloc(sizeof(rcContour)*maxContours, RC_ALLOC_PERM);
for (int j = 0; j < cset.nconts; ++j)
{
newConts[j] = cset.conts[j];
// Reset source pointers to prevent data deletion.
cset.conts[j].verts = 0;
cset.conts[j].rverts = 0;
}
rcFree(cset.conts);
cset.conts = newConts;
ctx->log(RC_LOG_WARNING, "rcBuildContours: Expanding max contours from %d to %d.", oldMax, maxContours);
}
rcContour* cont = &cset.conts[cset.nconts++];
cont->nverts = simplified.size()/4;
cont->verts = (int*)rcAlloc(sizeof(int)*cont->nverts*4, RC_ALLOC_PERM);
if (!cont->verts)
{
ctx->log(RC_LOG_ERROR, "rcBuildContours: Out of memory 'verts' (%d).", cont->nverts);
return false;
}
memcpy(cont->verts, &simplified[0], sizeof(int)*cont->nverts*4);
if (borderSize > 0)
{
// If the heightfield was build with bordersize, remove the offset.
for (int j = 0; j < cont->nverts; ++j)
{
int* v = &cont->verts[j*4];
v[0] -= borderSize;
v[2] -= borderSize;
}
}
cont->nrverts = verts.size()/4;
cont->rverts = (int*)rcAlloc(sizeof(int)*cont->nrverts*4, RC_ALLOC_PERM);
if (!cont->rverts)
{
ctx->log(RC_LOG_ERROR, "rcBuildContours: Out of memory 'rverts' (%d).", cont->nrverts);
return false;
}
memcpy(cont->rverts, &verts[0], sizeof(int)*cont->nrverts*4);
if (borderSize > 0)
{
// If the heightfield was build with bordersize, remove the offset.
for (int j = 0; j < cont->nrverts; ++j)
{
int* v = &cont->rverts[j*4];
v[0] -= borderSize;
v[2] -= borderSize;
}
}
cont->reg = reg;
cont->area = area;
}
}
}
}
// Merge holes if needed.
if (cset.nconts > 0)
{
// Calculate winding of all polygons.
rcScopedDelete<char> winding((char*)rcAlloc(sizeof(char)*cset.nconts, RC_ALLOC_TEMP));
if (!winding)
{
ctx->log(RC_LOG_ERROR, "rcBuildContours: Out of memory 'hole' (%d).", cset.nconts);
return false;
}
int nholes = 0;
for (int i = 0; i < cset.nconts; ++i)
{
rcContour& cont = cset.conts[i];
// If the contour is wound backwards, it is a hole.
winding[i] = calcAreaOfPolygon2D(cont.verts, cont.nverts) < 0 ? -1 : 1;
if (winding[i] < 0)
nholes++;
}
if (nholes > 0)
{
// Collect outline contour and holes contours per region.
// We assume that there is one outline and multiple holes.
const int nregions = chf.maxRegions+1;
rcScopedDelete<rcContourRegion> regions((rcContourRegion*)rcAlloc(sizeof(rcContourRegion)*nregions, RC_ALLOC_TEMP));
if (!regions)
{
ctx->log(RC_LOG_ERROR, "rcBuildContours: Out of memory 'regions' (%d).", nregions);
return false;
}
memset(regions, 0, sizeof(rcContourRegion)*nregions);
rcScopedDelete<rcContourHole> holes((rcContourHole*)rcAlloc(sizeof(rcContourHole)*cset.nconts, RC_ALLOC_TEMP));
if (!holes)
{
ctx->log(RC_LOG_ERROR, "rcBuildContours: Out of memory 'holes' (%d).", cset.nconts);
return false;
}
memset(holes, 0, sizeof(rcContourHole)*cset.nconts);
for (int i = 0; i < cset.nconts; ++i)
{
rcContour& cont = cset.conts[i];
// Positively would contours are outlines, negative holes.
if (winding[i] > 0)
{
if (regions[cont.reg].outline)
ctx->log(RC_LOG_ERROR, "rcBuildContours: Multiple outlines for region %d.", cont.reg);
regions[cont.reg].outline = &cont;
}
else
{
regions[cont.reg].nholes++;
}
}
int index = 0;
for (int i = 0; i < nregions; i++)
{
if (regions[i].nholes > 0)
{
regions[i].holes = &holes[index];
index += regions[i].nholes;
regions[i].nholes = 0;
}
}
for (int i = 0; i < cset.nconts; ++i)
{
rcContour& cont = cset.conts[i];
rcContourRegion& reg = regions[cont.reg];
if (winding[i] < 0)
reg.holes[reg.nholes++].contour = &cont;
}
// Finally merge each regions holes into the outline.
for (int i = 0; i < nregions; i++)
{
rcContourRegion& reg = regions[i];
if (!reg.nholes) continue;
if (reg.outline)
{
mergeRegionHoles(ctx, reg);
}
else
{
// The region does not have an outline.
// This can happen if the contour becaomes selfoverlapping because of
// too aggressive simplification settings.
ctx->log(RC_LOG_ERROR, "rcBuildContours: Bad outline for region %d, contour simplification is likely too aggressive.", i);
}
}
}
}
return true;
}