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scan.c
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/*
* scan.c
* kirk johnson
* august 1993
*
* Copyright (C) 1989, 1990, 1993-1995, 1999 Kirk Lauritz Johnson
*
* Parts of the source code (as marked) are:
* Copyright (C) 1989, 1990, 1991 by Jim Frost
* Copyright (C) 1992 by Jamie Zawinski <[email protected]>
*
* Permission to use, copy, modify and freely distribute xearth for
* non-commercial and not-for-profit purposes is hereby granted
* without fee, provided that both the above copyright notice and this
* permission notice appear in all copies and in supporting
* documentation.
*
* The author makes no representations about the suitability of this
* software for any purpose. It is provided "as is" without express or
* implied warranty.
*
* THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS,
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, INDIRECT
* OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
* LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
* NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include "xearth.h"
#define MAP_DATA_SCALE (30000)
#define XingTypeEntry (0)
#define XingTypeExit (1)
typedef struct {
int type;
int cidx;
double x, y;
double angle;
} EdgeXing;
void scan_map _P ((void));
void orth_scan_outline _P ((void));
void orth_scan_curves _P ((void));
double *orth_extract_curve _P ((int, short *));
void orth_scan_along_curve _P ((double *, double *, int));
void orth_find_edge_xing _P ((double *, double *, double *));
void orth_handle_xings _P ((void));
void orth_scan_arc _P ((double, double, double, double, double, double));
void merc_scan_outline _P ((void));
void merc_scan_curves _P ((void));
double *merc_extract_curve _P ((int, short *));
void merc_scan_along_curve _P ((double *, double *, int));
double merc_find_edge_xing _P ((double *, double *));
void merc_handle_xings _P ((void));
void merc_scan_edge _P ((EdgeXing *, EdgeXing *));
void cyl_scan_outline _P ((void));
void cyl_scan_curves _P ((void));
double *cyl_extract_curve _P ((int, short *));
void cyl_scan_along_curve _P ((double *, double *, int));
double cyl_find_edge_xing _P ((double *, double *));
void cyl_handle_xings _P ((void));
void cyl_scan_edge _P ((EdgeXing *, EdgeXing *));
void xing_error _P ((const char *, int, int, int, EdgeXing *));
void scan _P ((double, double, double, double));
void get_scanbits _P ((int));
static int double_comp _P ((const void *, const void *));
static int scanbit_comp _P ((const void *, const void *));
static int orth_edgexing_comp _P ((const void *, const void *));
static int merc_edgexing_comp _P ((const void *, const void *));
static int cyl_edgexing_comp _P ((const void *, const void *));
ViewPosInfo view_pos_info;
ProjInfo proj_info;
int first_scan = 1;
ExtArr scanbits;
ExtArr edgexings;
int min_y, max_y;
ExtArr *scanbuf;
static int
double_comp (a, b)
const void *a;
const void *b;
{
double val_a;
double val_b;
int rslt;
val_a = *((const double *) a);
val_b = *((const double *) b);
if (val_a < val_b)
rslt = -1;
else if (val_a > val_b)
rslt = 1;
else
rslt = 0;
return rslt;
}
static int
scanbit_comp (a, b)
const void *a;
const void *b;
{
return (((const ScanBit *) a)->y - ((const ScanBit *) b)->y);
}
static int
orth_edgexing_comp (a, b)
const void *a;
const void *b;
{
double angle_a;
double angle_b;
int rslt;
angle_a = ((const EdgeXing *) a)->angle;
angle_b = ((const EdgeXing *) b)->angle;
if (angle_a < angle_b)
rslt = -1;
else if (angle_a > angle_b)
rslt = 1;
else
rslt = 0;
return rslt;
}
static int
merc_edgexing_comp (a, b)
const void *a;
const void *b;
{
double val_a;
double val_b;
int rslt;
val_a = ((const EdgeXing *) a)->angle;
val_b = ((const EdgeXing *) b)->angle;
if (val_a < val_b) {
rslt = -1;
} else if (val_a > val_b) {
rslt = 1;
} else if (val_a == 0) {
val_a = ((const EdgeXing *) a)->y;
val_b = ((const EdgeXing *) b)->y;
if (val_a < val_b)
rslt = -1;
else if (val_a > val_b)
rslt = 1;
else
rslt = 0;
} else if (val_a == 2) {
val_a = ((const EdgeXing *) a)->y;
val_b = ((const EdgeXing *) b)->y;
if (val_a > val_b)
rslt = -1;
else if (val_a < val_b)
rslt = 1;
else
rslt = 0;
} else {
/* keep lint happy */
rslt = 0;
assert (0);
}
return rslt;
}
static int
cyl_edgexing_comp (a, b)
const void *a;
const void *b;
{
double val_a;
double val_b;
int rslt;
val_a = ((const EdgeXing *) a)->angle;
val_b = ((const EdgeXing *) b)->angle;
if (val_a < val_b) {
rslt = -1;
} else if (val_a > val_b) {
rslt = 1;
} else if (val_a == 0) {
val_a = ((const EdgeXing *) a)->y;
val_b = ((const EdgeXing *) b)->y;
if (val_a < val_b)
rslt = -1;
else if (val_a > val_b)
rslt = 1;
else
rslt = 0;
} else if (val_a == 2) {
val_a = ((const EdgeXing *) a)->y;
val_b = ((const EdgeXing *) b)->y;
if (val_a > val_b)
rslt = -1;
else if (val_a < val_b)
rslt = 1;
else
rslt = 0;
} else {
/* keep lint happy */
rslt = 0;
assert (0);
}
return rslt;
}
void
scan_map ()
{
int i;
ViewPosInfo *vpi;
ProjInfo *pi;
vpi = &view_pos_info;
vpi->cos_lat = cos (view_lat * (M_PI / 180));
vpi->sin_lat = sin (view_lat * (M_PI / 180));
vpi->cos_lon = cos (view_lon * (M_PI / 180));
vpi->sin_lon = sin (view_lon * (M_PI / 180));
vpi->cos_rot = cos (view_rot * (M_PI / 180));
vpi->sin_rot = sin (view_rot * (M_PI / 180));
pi = &proj_info;
if (proj_type == ProjTypeOrthographic) {
pi->proj_scale = ((hght < wdth) ? hght : wdth) * (view_mag / 2) * 0.99;
} else {
/* proj_type is either ProjTypeMercator or ProjTypeCylindrical
*/
pi->proj_scale = (view_mag * wdth) / (2 * M_PI);
}
pi->proj_xofs = (double) wdth / 2 + shift_x;
pi->proj_yofs = (double) hght / 2 + shift_y;
pi->inv_proj_scale = 1 / pi->proj_scale;
/* the first time through, allocate scanbits and edgexings;
* on subsequent passes, simply reset them.
*/
if (first_scan) {
scanbits = extarr_alloc (sizeof (ScanBit));
edgexings = extarr_alloc (sizeof (EdgeXing));
} else {
scanbits->count = 0;
edgexings->count = 0;
}
/* maybe only allocate these once and reset them on
* subsequent passes (like scanbits and edgexings)?
*/
scanbuf = (ExtArr *) malloc ((unsigned) sizeof (ExtArr) * hght);
assert (scanbuf != NULL);
for (i = 0; i < hght; i++)
scanbuf[i] = extarr_alloc (sizeof (double));
if (proj_type == ProjTypeOrthographic) {
orth_scan_outline ();
orth_scan_curves ();
} else if (proj_type == ProjTypeMercator) {
merc_scan_outline ();
merc_scan_curves ();
} else { /* (proj_type == ProjTypeCylindrical) */
cyl_scan_outline ();
cyl_scan_curves ();
}
for (i = 0; i < hght; i++)
extarr_free (scanbuf[i]);
free (scanbuf);
qsort (scanbits->body, scanbits->count, sizeof (ScanBit), scanbit_comp);
first_scan = 0;
}
void
orth_scan_outline ()
{
min_y = hght;
max_y = -1;
orth_scan_arc (1.0, 0.0, 0.0, 1.0, 0.0, (2 * M_PI));
get_scanbits (64);
}
void
orth_scan_curves ()
{
int i;
int cidx;
int npts;
int val;
short *raw;
double *pos;
double *prev;
double *curr;
cidx = 0;
raw = map_data;
while (1) {
npts = raw[0];
if (npts == 0)
break;
val = raw[1];
raw += 2;
pos = orth_extract_curve (npts, raw);
prev = pos + (npts - 1) * 3;
curr = pos;
min_y = hght;
max_y = -1;
for (i = 0; i < npts; i++) {
orth_scan_along_curve (prev, curr, cidx);
prev = curr;
curr += 3;
}
free (pos);
if (edgexings->count > 0)
orth_handle_xings ();
if (min_y <= max_y)
get_scanbits (val);
cidx += 1;
raw += 3 * npts;
}
}
double *
orth_extract_curve (npts, data)
int npts;
short *data;
{
int i;
int x, y, z;
double scale;
double *pos;
double *rslt;
rslt = (double *) malloc ((unsigned) sizeof (double) * 3 * npts);
assert (rslt != NULL);
x = 0;
y = 0;
z = 0;
scale = 1.0 / MAP_DATA_SCALE;
pos = rslt;
for (i = 0; i < npts; i++) {
x += data[0];
y += data[1];
z += data[2];
pos[0] = x * scale;
pos[1] = y * scale;
pos[2] = z * scale;
XFORM_ROTATE (pos, view_pos_info);
data += 3;
pos += 3;
}
return rslt;
}
void
orth_scan_along_curve (prev, curr, cidx)
double *prev;
double *curr;
int cidx;
{
double extra[3];
EdgeXing *xing;
if (prev[2] <= 0) { /* prev not visible */
if (curr[2] <= 0)
return; /* neither point visible */
orth_find_edge_xing (prev, curr, extra);
/* extra[] is an edge crossing (entry point) */
xing = (EdgeXing *) extarr_next (edgexings);
xing->type = XingTypeEntry;
xing->cidx = cidx;
xing->x = extra[0];
xing->y = extra[1];
xing->angle = atan2 (extra[1], extra[0]);
prev = extra;
} else if (curr[2] <= 0) { /* curr not visible */
orth_find_edge_xing (prev, curr, extra);
/* extra[] is an edge crossing (exit point) */
xing = (EdgeXing *) extarr_next (edgexings);
xing->type = XingTypeExit;
xing->cidx = cidx;
xing->x = extra[0];
xing->y = extra[1];
xing->angle = atan2 (extra[1], extra[0]);
curr = extra;
}
scan (XPROJECT (prev[0]), YPROJECT (prev[1]),
XPROJECT (curr[0]), YPROJECT (curr[1]));
}
void
orth_find_edge_xing (prev, curr, rslt)
double *prev;
double *curr;
double *rslt;
{
double tmp;
double r0, r1;
tmp = curr[2] / (curr[2] - prev[2]);
r0 = curr[0] - tmp * (curr[0] - prev[0]);
r1 = curr[1] - tmp * (curr[1] - prev[1]);
tmp = sqrt ((r0 * r0) + (r1 * r1));
rslt[0] = r0 / tmp;
rslt[1] = r1 / tmp;
rslt[2] = 0;
}
void
orth_handle_xings ()
{
int i;
int nxings;
EdgeXing *xings;
EdgeXing *from;
EdgeXing *to;
xings = (EdgeXing *) edgexings->body;
nxings = edgexings->count;
assert ((nxings % 2) == 0);
qsort (xings, (unsigned) nxings, sizeof (EdgeXing), orth_edgexing_comp);
if (xings[0].type == XingTypeExit) {
for (i = 0; i < nxings; i += 2) {
from = &(xings[i]);
to = &(xings[i + 1]);
if ((from->type != XingTypeExit) || (to->type != XingTypeEntry))
xing_error (__FILE__, __LINE__, i, nxings, xings);
orth_scan_arc (from->x, from->y, from->angle,
to->x, to->y, to->angle);
}
} else {
from = &(xings[nxings - 1]);
to = &(xings[0]);
if ((from->type != XingTypeExit) ||
(to->type != XingTypeEntry) || (from->angle < to->angle))
xing_error (__FILE__, __LINE__, nxings - 1, nxings, xings);
orth_scan_arc (from->x, from->y, from->angle,
to->x, to->y, to->angle + (2 * M_PI));
for (i = 1; i < (nxings - 1); i += 2) {
from = &(xings[i]);
to = &(xings[i + 1]);
if ((from->type != XingTypeExit) || (to->type != XingTypeEntry))
xing_error (__FILE__, __LINE__, i, nxings, xings);
orth_scan_arc (from->x, from->y, from->angle,
to->x, to->y, to->angle);
}
}
edgexings->count = 0;
}
void
orth_scan_arc (x_0, y_0, a_0, x_1, y_1, a_1)
double x_0, y_0, a_0;
double x_1, y_1, a_1;
{
int i;
int lo, hi;
double angle, step;
double prev_x, prev_y;
double curr_x, curr_y;
double c_step, s_step;
double arc_x, arc_y;
double tmp;
assert (a_0 < a_1);
step = proj_info.inv_proj_scale * 10;
if (step > 0.05)
step = 0.05;
lo = ceil (a_0 / step);
hi = floor (a_1 / step);
prev_x = XPROJECT (x_0);
prev_y = YPROJECT (y_0);
if (lo <= hi) {
c_step = cos (step);
s_step = sin (step);
angle = lo * step;
arc_x = cos (angle);
arc_y = sin (angle);
for (i = lo; i <= hi; i++) {
curr_x = XPROJECT (arc_x);
curr_y = YPROJECT (arc_y);
scan (prev_x, prev_y, curr_x, curr_y);
/* instead of repeatedly calling cos() and sin() to get the next
* values for arc_x and arc_y, simply rotate the existing values
*/
tmp = (c_step * arc_x) - (s_step * arc_y);
arc_y = (s_step * arc_x) + (c_step * arc_y);
arc_x = tmp;
prev_x = curr_x;
prev_y = curr_y;
}
}
curr_x = XPROJECT (x_1);
curr_y = YPROJECT (y_1);
scan (prev_x, prev_y, curr_x, curr_y);
}
void
merc_scan_outline ()
{
double left, right;
double top, bottom;
min_y = hght;
max_y = -1;
left = XPROJECT (-M_PI);
right = XPROJECT (M_PI);
top = YPROJECT (BigNumber);
bottom = YPROJECT (-BigNumber);
scan (right, top, left, top);
scan (left, top, left, bottom);
scan (left, bottom, right, bottom);
scan (right, bottom, right, top);
get_scanbits (64);
}
void
merc_scan_curves ()
{
int i;
int cidx;
int npts;
int val;
short *raw;
double *pos;
double *prev;
double *curr;
cidx = 0;
raw = map_data;
while (1) {
npts = raw[0];
if (npts == 0)
break;
val = raw[1];
raw += 2;
pos = merc_extract_curve (npts, raw);
prev = pos + (npts - 1) * 5;
curr = pos;
min_y = hght;
max_y = -1;
for (i = 0; i < npts; i++) {
merc_scan_along_curve (prev, curr, cidx);
prev = curr;
curr += 5;
}
free (pos);
if (edgexings->count > 0)
merc_handle_xings ();
if (min_y <= max_y)
get_scanbits (val);
cidx += 1;
raw += 3 * npts;
}
}
double *
merc_extract_curve (npts, data)
int npts;
short *data;
{
int i;
int x, y, z;
double scale;
double *pos;
double *rslt;
rslt = (double *) malloc ((unsigned) sizeof (double) * 5 * npts);
assert (rslt != NULL);
x = 0;
y = 0;
z = 0;
scale = 1.0 / MAP_DATA_SCALE;
pos = rslt;
for (i = 0; i < npts; i++) {
x += data[0];
y += data[1];
z += data[2];
pos[0] = x * scale;
pos[1] = y * scale;
pos[2] = z * scale;
XFORM_ROTATE (pos, view_pos_info);
/* apply mercator projection
*/
pos[3] = MERCATOR_X (pos[0], pos[2]);
pos[4] = MERCATOR_Y (pos[1]);
data += 3;
pos += 5;
}
return rslt;
}
void
merc_scan_along_curve (prev, curr, cidx)
double *prev;
double *curr;
int cidx;
{
double px, py;
double cx, cy;
double dx;
double mx, my;
EdgeXing *xing;
px = prev[3];
cx = curr[3];
py = prev[4];
cy = curr[4];
dx = cx - px;
if (dx > 0) {
/* curr to the right of prev
*/
if (dx > ((2 * M_PI) - dx)) {
/* vertical edge crossing to the left of prev
*/
/* find exit point (left edge) */
mx = -M_PI;
my = merc_find_edge_xing (prev, curr);
/* scan from prev to exit point */
scan (XPROJECT (px), YPROJECT (py), XPROJECT (mx), YPROJECT (my));
/* (mx, my) is an edge crossing (exit point) */
xing = (EdgeXing *) extarr_next (edgexings);
xing->type = XingTypeExit;
xing->cidx = cidx;
xing->x = mx;
xing->y = my;
xing->angle = 2; /* left edge */
/* scan from entry point (right edge) to curr */
mx = M_PI;
scan (XPROJECT (mx), YPROJECT (my), XPROJECT (cx), YPROJECT (cy));
/* (mx, my) is an edge crossing (entry point) */
xing = (EdgeXing *) extarr_next (edgexings);
xing->type = XingTypeEntry;
xing->cidx = cidx;
xing->x = mx;
xing->y = my;
xing->angle = 0; /* right edge */
} else {
/* no vertical edge crossing
*/
scan (XPROJECT (px), YPROJECT (py), XPROJECT (cx), YPROJECT (cy));
}
} else {
/* curr to the left of prev
*/
dx = -dx;
if (dx > ((2 * M_PI) - dx)) {
/* vertical edge crossing to the right of prev
*/
/* find exit point (right edge) */
mx = M_PI;
my = merc_find_edge_xing (prev, curr);
/* scan from prev to exit point */
scan (XPROJECT (px), YPROJECT (py), XPROJECT (mx), YPROJECT (my));
/* (mx, my) is an edge crossing (exit point) */
xing = (EdgeXing *) extarr_next (edgexings);
xing->type = XingTypeExit;
xing->cidx = cidx;
xing->x = mx;
xing->y = my;
xing->angle = 0; /* right edge */
/* scan from entry point (left edge) to curr */
mx = -M_PI;
scan (XPROJECT (mx), YPROJECT (my), XPROJECT (cx), YPROJECT (cy));
/* (mx, my) is an edge crossing (entry point) */
xing = (EdgeXing *) extarr_next (edgexings);
xing->type = XingTypeEntry;
xing->cidx = cidx;
xing->x = mx;
xing->y = my;
xing->angle = 2; /* left edge */
} else {
/* no vertical edge crossing
*/
scan (XPROJECT (px), YPROJECT (py), XPROJECT (cx), YPROJECT (cy));
}
}
}
double
merc_find_edge_xing (prev, curr)
double *prev;
double *curr;
{
double ratio;
double scale;
double z1, z2;
double rslt;
if (curr[0] != 0) {
ratio = (prev[0] / curr[0]);
z1 = prev[1] - (ratio * curr[1]);
z2 = prev[2] - (ratio * curr[2]);
} else {
z1 = curr[1];
z2 = curr[2];
}
scale = ((z2 > 0) ? -1 : 1) / sqrt ((z1 * z1) + (z2 * z2));
z1 *= scale;
rslt = MERCATOR_Y (z1);
return rslt;
}
void
merc_handle_xings ()
{
int i;
int nxings;
EdgeXing *xings;
EdgeXing *from;
EdgeXing *to;
xings = (EdgeXing *) edgexings->body;
nxings = edgexings->count;
assert ((nxings % 2) == 0);
qsort (xings, (unsigned) nxings, sizeof (EdgeXing), merc_edgexing_comp);
if (xings[0].type == XingTypeExit) {
for (i = 0; i < nxings; i += 2) {
from = &(xings[i]);
to = &(xings[i + 1]);
if ((from->type != XingTypeExit) || (to->type != XingTypeEntry))
xing_error (__FILE__, __LINE__, i, nxings, xings);
merc_scan_edge (from, to);
}
} else {
from = &(xings[nxings - 1]);
to = &(xings[0]);
if ((from->type != XingTypeExit) ||
(to->type != XingTypeEntry) || (from->angle < to->angle))
xing_error (__FILE__, __LINE__, nxings - 1, nxings, xings);
merc_scan_edge (from, to);
for (i = 1; i < (nxings - 1); i += 2) {
from = &(xings[i]);
to = &(xings[i + 1]);
if ((from->type != XingTypeExit) || (to->type != XingTypeEntry))
xing_error (__FILE__, __LINE__, i, nxings, xings);
merc_scan_edge (from, to);
}
}
edgexings->count = 0;
}
void
merc_scan_edge (from, to)
EdgeXing *from;
EdgeXing *to;
{
int s0, s1, s_new;
double x_0, x_1, x_new;
double y_0, y_1, y_new;
s0 = from->angle;
x_0 = XPROJECT (from->x);
y_0 = YPROJECT (from->y);
s1 = to->angle;
x_1 = XPROJECT (to->x);
y_1 = YPROJECT (to->y);
while (s0 != s1) {
switch (s0) {
case 0:
x_new = XPROJECT (M_PI);
y_new = YPROJECT (BigNumber);
s_new = 1;
break;
case 1:
x_new = XPROJECT (-M_PI);
y_new = YPROJECT (BigNumber);
s_new = 2;
break;
case 2:
x_new = XPROJECT (-M_PI);
y_new = YPROJECT (-BigNumber);
s_new = 3;
break;
case 3:
x_new = XPROJECT (M_PI);
y_new = YPROJECT (-BigNumber);
s_new = 0;
break;
default:
/* keep lint happy */
x_new = 0;
y_new = 0;
s_new = 0;
assert (0);
}
scan (x_0, y_0, x_new, y_new);
x_0 = x_new;
y_0 = y_new;
s0 = s_new;
}
scan (x_0, y_0, x_1, y_1);
}
void
cyl_scan_outline ()
{
double left, right;
double top, bottom;
min_y = hght;
max_y = -1;
left = XPROJECT (-M_PI);
right = XPROJECT (M_PI);
top = YPROJECT (BigNumber);
bottom = YPROJECT (-BigNumber);
scan (right, top, left, top);
scan (left, top, left, bottom);
scan (left, bottom, right, bottom);
scan (right, bottom, right, top);
get_scanbits (64);
}
void
cyl_scan_curves ()
{
int i;
int cidx;
int npts;
int val;
short *raw;
double *pos;
double *prev;
double *curr;
cidx = 0;
raw = map_data;
while (1) {
npts = raw[0];
if (npts == 0)
break;
val = raw[1];
raw += 2;
pos = cyl_extract_curve (npts, raw);
prev = pos + (npts - 1) * 5;
curr = pos;
min_y = hght;
max_y = -1;
for (i = 0; i < npts; i++) {
cyl_scan_along_curve (prev, curr, cidx);
prev = curr;
curr += 5;
}
free (pos);
if (edgexings->count > 0)
cyl_handle_xings ();
if (min_y <= max_y)
get_scanbits (val);
cidx += 1;
raw += 3 * npts;
}
}
double *
cyl_extract_curve (npts, data)
int npts;
short *data;
{
int i;
int x, y, z;
double scale;
double *pos;
double *rslt;
rslt = (double *) malloc ((unsigned) sizeof (double) * 5 * npts);
assert (rslt != NULL);
x = 0;
y = 0;
z = 0;
scale = 1.0 / MAP_DATA_SCALE;
pos = rslt;
for (i = 0; i < npts; i++) {
x += data[0];
y += data[1];
z += data[2];
pos[0] = x * scale;
pos[1] = y * scale;
pos[2] = z * scale;
XFORM_ROTATE (pos, view_pos_info);
/* apply cylindrical projection
*/