Recast: make detail mesh edge detection more robust

Merge recastnavitagion/recastnavitagion@c393777d26
Instead of using a distance check which can fail at large magnitudes due
to low precision we can check whether the edges are actually on the
hull.
This commit is contained in:
Kawe Mazidjatari 2023-12-26 16:54:29 +01:00
parent e3bf2036b3
commit 1f7bbe5b92

View File

@ -735,6 +735,40 @@ inline float getJitterY(const int i)
return (((i * 0xd8163841) & 0xffff) / 65535.0f * 2.0f) - 1.0f;
}
static bool onHull(int a, int b, int nhull, int* hull)
{
// All internal sampled points come after the hull so we can early out for those.
if (a >= nhull || b >= nhull)
return false;
for (int j = nhull - 1, i = 0; i < nhull; j = i++)
{
if (a == hull[j] && b == hull[i])
return true;
}
return false;
}
// Find edges that lie on hull and mark them as such.
static void setTriFlags(rcIntArray& tris, int nhull, int* hull)
{
// Matches DT_DETAIL_EDGE_BOUNDARY
const int DETAIL_EDGE_BOUNDARY = 0x1;
for (int i = 0; i < tris.size(); i += 4)
{
int a = tris[i + 0];
int b = tris[i + 2];
int c = tris[i + 1];
unsigned short flags = 0;
flags |= (onHull(a, b, nhull, hull) ? DETAIL_EDGE_BOUNDARY : 0) << 0;
flags |= (onHull(b, c, nhull, hull) ? DETAIL_EDGE_BOUNDARY : 0) << 2;
flags |= (onHull(c, a, nhull, hull) ? DETAIL_EDGE_BOUNDARY : 0) << 4;
tris[i + 3] = (int)flags;
}
}
static bool buildPolyDetail(rcContext* ctx, const float* in, const int nin,
const float sampleDist, const float sampleMaxError,
const int heightSearchRadius, const rcCompactHeightfield& chf,
@ -872,6 +906,7 @@ static bool buildPolyDetail(rcContext* ctx, const float* in, const int nin,
if (minExtent < sampleDist*2)
{
triangulateHull(nverts, verts, nhull, hull, nin, tris);
setTriFlags(tris, nhull, hull);
return true;
}
@ -977,6 +1012,8 @@ static bool buildPolyDetail(rcContext* ctx, const float* in, const int nin,
ctx->log(RC_LOG_ERROR, "rcBuildPolyMeshDetail: Shrinking triangle count from %d to max %d.", ntris, MAX_TRIS);
}
setTriFlags(tris, nhull, hull);
return true;
}
@ -1238,31 +1275,6 @@ static void getHeightData(rcContext* ctx, const rcCompactHeightfield& chf,
}
}
static unsigned char getEdgeFlags(const float* va, const float* vb,
const float* vpoly, const int npoly)
{
// The flag returned by this function matches dtDetailTriEdgeFlags in Detour.
// Figure out if edge (va,vb) is part of the polygon boundary.
static const float thrSqr = rcSqr(0.001f);
for (int i = 0, j = npoly-1; i < npoly; j=i++)
{
if (distancePtSeg2d(va, &vpoly[j*3], &vpoly[i*3]) < thrSqr &&
distancePtSeg2d(vb, &vpoly[j*3], &vpoly[i*3]) < thrSqr)
return 1;
}
return 0;
}
static unsigned char getTriFlags(const float* va, const float* vb, const float* vc,
const float* vpoly, const int npoly)
{
unsigned char flags = 0;
flags |= getEdgeFlags(va,vb,vpoly,npoly) << 0;
flags |= getEdgeFlags(vb,vc,vpoly,npoly) << 2;
flags |= getEdgeFlags(vc,va,vpoly,npoly) << 4;
return flags;
}
/// @par
///
/// See the #rcConfig documentation for more information on the configuration parameters.
@ -1479,7 +1491,7 @@ bool rcBuildPolyMeshDetail(rcContext* ctx, const rcPolyMesh& mesh, const rcCompa
dmesh.tris[dmesh.ntris*4+0] = (unsigned char)t[0];
dmesh.tris[dmesh.ntris*4+1] = (unsigned char)t[2];
dmesh.tris[dmesh.ntris*4+2] = (unsigned char)t[1];
dmesh.tris[dmesh.ntris*4+3] = getTriFlags(&verts[t[0]*3], &verts[t[2]*3], &verts[t[1]*3], poly, npoly);
dmesh.tris[dmesh.ntris*4+3] = (unsigned char)t[3];
dmesh.ntris++;
}
}