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Skip one-pixel gaps in tracer

for-marcan
Hector Martin 2011-03-12 01:23:35 +01:00
parent fd98c62e14
commit 5df46f50ba
1 changed files with 27 additions and 5 deletions
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32
tools/trace.c
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@ -44,7 +44,7 @@ object start/end points near the edges of the screen (less visible).
#define ABS(a) ((a)<0?(-(a)):(a))
#define OVERDRAW 8
#define OVERDRAW 6
//#define DEBUG
@ -57,6 +57,9 @@ static int tframe = 0;
static const int tdx[8] = { 1, 1, 0, -1, -1, -1, 0, 1 };
static const int tdy[8] = { 0, -1, -1, -1, 0, 1, 1, 1 };
static const int tdx2[16] = { 2, 2, 2, 1, 0, -1, -2, -2, -2, -2, -2, -1, 0, 1, 2, 2 };
static const int tdy2[16] = { 0, -1, -2, -2, -2, -2, -2, -1, 0, 1, 2, 2, 2, 2, 2, 1 };
static int trace_pixels(uint8_t *buf, int s, int decimate, int *cx, int *cy, int flag)
{
int i;
@ -111,9 +114,9 @@ static int trace_pixels(uint8_t *buf, int s, int decimate, int *cx, int *cy, int
y += tdy[dir];
} else {
// no, check for lowest angle path
int ddir;
int ddir, ndir;
for (ddir=1; ddir<=4; ddir++) {
int ndir = (dir + ddir) % 8;
ndir = (dir + ddir) % 8;
if (buf[idx+tdx[ndir]+s*tdy[ndir]] & flag) {
dir = ndir;
x += tdx[ndir];
@ -129,8 +132,27 @@ static int trace_pixels(uint8_t *buf, int s, int decimate, int *cx, int *cy, int
}
}
if (ddir > 4) {
lidx = idx;
break;
// now try the distance-2 neighborhood, can we skip a pixel?
for (ddir=0; ddir<=8; ddir++) {
ndir = (2*dir + ddir) % 16;
if (buf[idx+tdx2[ndir]+s*tdy2[ndir]] & flag) {
dir = (dir + ddir/2) % 8;
x += tdx2[ndir];
y += tdy2[ndir];
break;
}
ndir = (16 + 2*dir - ddir) % 16;
if (buf[idx+tdx2[ndir]+s*tdy2[ndir]] & flag) {
dir = (8 + dir - ddir/2) % 8;
x += tdx2[ndir];
y += tdy2[ndir];
break;
}
}
if (ddir > 8) {
lidx = idx;
break;
}
}
}
if (!start) {