server_common/recastnavigation_v1.6.0
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Rasterization optimization: replaced clipping for each individual cell. the clipping line/plane between two adjacent cells is common so data from former cell can be reused if we keep track of the "remaining polygon".

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axelrodR 2014-01-15 14:14:08 +02:00
parent 8e4633c64b
commit e063ba6f5a
1 changed files with 49 additions and 30 deletions
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75
Recast/Source/RecastRasterization.cpp
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@ -169,36 +169,53 @@ void rcAddSpan(rcContext* /*ctx*/, rcHeightfield& hf, const int x, const int y,
addSpan(hf, x,y, smin, smax, area, flagMergeThr);
}
static int clipPoly(const float* in, int n, float* out, float pnx, float pnz, float pd)
// divides a convex polygons into two convex polygons on both sides of a line
static void dividePoly(const float* in, int nbIn,
float* out1, int* nb1,
float* out2, int* nb2,
float x, int axis)
{
float d[12];
for (int i = 0; i < n; ++i)
d[i] = pnx*in[i*3+0] + pnz*in[i*3+2] + pd;
for (int i = 0; i < nbIn; ++i)
d[i] = x - in[i*3+axis];
int m = 0;
for (int i = 0, j = n-1; i < n; j=i, ++i)
int m = 0, n = 0;
for (int i = 0, j = nbIn-1; i < nbIn; j=i, ++i)
{
bool ina = d[j] >= 0;
bool inb = d[i] >= 0;
if (ina != inb)
{
float s = d[j] / (d[j] - d[i]);
out[m*3+0] = in[j*3+0] + (in[i*3+0] - in[j*3+0])*s;
out[m*3+1] = in[j*3+1] + (in[i*3+1] - in[j*3+1])*s;
out[m*3+2] = in[j*3+2] + (in[i*3+2] - in[j*3+2])*s;
out1[m*3+0] = in[j*3+0] + (in[i*3+0] - in[j*3+0])*s;
out1[m*3+1] = in[j*3+1] + (in[i*3+1] - in[j*3+1])*s;
out1[m*3+2] = in[j*3+2] + (in[i*3+2] - in[j*3+2])*s;
rcVcopy(out2 + n*3, out1 + m*3);
m++;
n++;
}
if (inb)
{
out[m*3+0] = in[i*3+0];
out[m*3+1] = in[i*3+1];
out[m*3+2] = in[i*3+2];
out1[m*3+0] = in[i*3+0];
out1[m*3+1] = in[i*3+1];
out1[m*3+2] = in[i*3+2];
m++;
if (d[0] != 0) // not on the line
continue;
}
// i-th point is on the other half plane or on the line
out2[n*3+0] = in[i*3+0];
out2[n*3+1] = in[i*3+1];
out2[n*3+2] = in[i*3+2];
n++;
}
return m;
*nb1 = m;
*nb2 = n;
}
static void rasterizeTri(const float* v0, const float* v1, const float* v2,
const unsigned char area, rcHeightfield& hf,
const float* bmin, const float* bmax,
@ -229,21 +246,23 @@ static void rasterizeTri(const float* v0, const float* v1, const float* v2,
y1 = rcClamp(y1, 0, h-1);
// Clip the triangle into all grid cells it touches.
float in[7*3], out[7*3], inrow[7*3];
float buf[7*3*4];
float *in = buf, *inrow = buf+7*3, *p1 = inrow+7*3, *p2 = p1+7*3;
for (int y = y0; y <= y1; ++y)
{
// Clip polygon to row.
rcVcopy(&in[0], v0);
rcVcopy(&in[1*3], v1);
rcVcopy(&in[2*3], v2);
int nvrow = 3;
int nvrow, nvIn = 3;
for (int y = y0; y <= y1; ++y)
{
// Clip polygon to row. Store the remaining polygon as well
const float cz = bmin[2] + y*cs;
nvrow = clipPoly(in, nvrow, out, 0, 1, -cz);
if (nvrow < 3) continue;
nvrow = clipPoly(out, nvrow, inrow, 0, -1, cz+cs);
dividePoly(in, nvIn, inrow, &nvrow, p1, &nvIn, cz+cs, 2);
rcSwap(in, p1);
if (nvrow < 3) continue;
// find the horizontal bounds in the row
float minX = inrow[0], maxX = inrow[0];
for (int i=1; i<nvrow; ++i)
{
@ -255,22 +274,22 @@ static void rasterizeTri(const float* v0, const float* v1, const float* v2,
x0 = rcClamp(x0, 0, w-1);
x1 = rcClamp(x1, 0, w-1);
int nv, nv2 = nvrow;
for (int x = x0; x <= x1; ++x)
{
// Clip polygon to column.
int nv = nvrow;
// Clip polygon to column. store the remaining polygon as well
const float cx = bmin[0] + x*cs;
nv = clipPoly(inrow, nv, out, 1, 0, -cx);
if (nv < 3) continue;
nv = clipPoly(out, nv, in, -1, 0, cx+cs);
dividePoly(inrow, nv2, p1, &nv, p2, &nv2, cx+cs, 0);
rcSwap(inrow, p2);
if (nv < 3) continue;
// Calculate min and max of the span.
float smin = in[1], smax = in[1];
float smin = p1[1], smax = p1[1];
for (int i = 1; i < nv; ++i)
{
smin = rcMin(smin, in[i*3+1]);
smax = rcMax(smax, in[i*3+1]);
smin = rcMin(smin, p1[i*3+1]);
smax = rcMax(smax, p1[i*3+1]);
}
smin -= bmin[1];
smax -= bmin[1];