/* Compute the intersection of two edges. The result is provided as a
* coordinate pair of 128-bit integers.
*
* Returns %CAIRO_BO_STATUS_INTERSECTION if there is an intersection
* that is within both edges, %CAIRO_BO_STATUS_NO_INTERSECTION if the
* intersection of the lines defined by the edges occurs outside of
* one or both edges, and %CAIRO_BO_STATUS_PARALLEL if the two edges
* are exactly parallel.
*
* Note that when determining if a candidate intersection is "inside"
* an edge, we consider both the infinitesimal shortening and the
* infinitesimal tilt rules described by John Hobby. Specifically, if
* the intersection is exactly the same as an edge point, it is
* effectively outside (no intersection is returned). Also, if the
* intersection point has the same
*/
static cairo_bool_t
_cairo_bo_edge_intersect (cairo_bo_edge_t *a,
cairo_bo_edge_t *b,
cairo_bo_point32_t *intersection)
{
cairo_bo_intersect_point_t quorem;
if (! intersect_lines (a, b, &quorem))
return FALSE;
if (! _cairo_bo_edge_contains_intersect_point (a, &quorem))
return FALSE;
if (! _cairo_bo_edge_contains_intersect_point (b, &quorem))
return FALSE;
/* Now that we've correctly compared the intersection point and
* determined that it lies within the edge, then we know that we
* no longer need any more bits of storage for the intersection
* than we do for our edge coordinates. We also no longer need the
* remainder from the division. */
intersection->x = quorem.x.ordinate;
intersection->y = quorem.y.ordinate;
return TRUE;
}
void quadstretch(float x,float y,float l,float t,
float w,float h,float *qx,float *qy,float *ret){
/*
--x & y are the original point
-- l & t are left and top of original rect
-- w & h are width and height of original rect
--qx and qy are arrays of 4 points describing the new quad.
--1. strip it down to floats between 0 and 1
-- so we know where it is, relative to the boundaries.
*/
float xF = (x-l)/float(w);
float yF = (y-t)/float(h);
// 2. generate "vertical"
float interpTop[2];
interpolatePoints(qx[0],qy[0],qx[1],qy[1],xF,interpTop);
float interpBottom[2];
interpolatePoints(qx[3],qy[3],qx[2],qy[2],xF,interpBottom);
//3. generate "horizontal"
float interpLeft[2];
interpolatePoints(qx[0],qy[0],qx[3],qy[3],yF,interpLeft);
float interpRight[2];
interpolatePoints(qx[1],qy[1],qx[2],qy[2],yF,interpRight);
intersect_lines(interpTop [0], interpTop[1],
interpBottom[0],interpBottom[1],
interpLeft [0], interpLeft[1],
interpRight [0], interpRight[1],ret);
}
int check_intersection(double *int_x, double *int_y,
double beam_x, double beam_y, double
dbeam_x, double dbeam_y,
double x1, double y1, double x2, double y2)
{
if (beam_x < x1 || beam_x > x2 || beam_y < y1 || beam_y > y2)
return FALSE; /* beam origin not in objext x1y1-x2y2 */
if ((dbeam_y < 0.0 &&
intersect_lines(int_x, int_y, x1, y1, x2-x1, 0.0,
beam_x, beam_y, dbeam_x, dbeam_y, 0)) ||
(dbeam_x < 0.0 &&
intersect_lines(int_x, int_y, x1, y1, 0.0, y2-y1,
beam_x, beam_y, dbeam_x, dbeam_y, 1)) ||
(dbeam_y > 0.0 &&
intersect_lines(int_x, int_y, x1, y2, x2-x1, 0.0,
beam_x, beam_y, dbeam_x, dbeam_y, 0)) ||
(dbeam_x > 0.0 &&
intersect_lines(int_x, int_y, x2, y1, 0.0, y2-y1,
beam_x, beam_y, dbeam_x, dbeam_y, 1))) {
return TRUE;
}
return FALSE;
}
/* Compute the intersection of two edges. The result is provided as a
* coordinate pair of 128-bit integers.
*
* Returns %CAIRO_BO_STATUS_INTERSECTION if there is an intersection
* that is within both edges, %CAIRO_BO_STATUS_NO_INTERSECTION if the
* intersection of the lines defined by the edges occurs outside of
* one or both edges, and %CAIRO_BO_STATUS_PARALLEL if the two edges
* are exactly parallel.
*
* Note that when determining if a candidate intersection is "inside"
* an edge, we consider both the infinitesimal shortening and the
* infinitesimal tilt rules described by John Hobby. Specifically, if
* the intersection is exactly the same as an edge point, it is
* effectively outside (no intersection is returned). Also, if the
* intersection point has the same
*/
static cairo_bool_t
_cairo_bo_edge_intersect (cairo_bo_edge_t *a,
cairo_bo_edge_t *b,
cairo_bo_intersect_point_t *intersection)
{
if (! intersect_lines (a, b, intersection))
return FALSE;
if (! _cairo_bo_edge_contains_intersect_point (a, intersection))
return FALSE;
if (! _cairo_bo_edge_contains_intersect_point (b, intersection))
return FALSE;
return TRUE;
}
static void bloat_quad(const SkPoint qpts[3], const SkMatrix* toDevice,
const SkMatrix* toSrc, BezierVertex verts[kQuadNumVertices]) {
SkASSERT(!toDevice == !toSrc);
// original quad is specified by tri a,b,c
SkPoint a = qpts[0];
SkPoint b = qpts[1];
SkPoint c = qpts[2];
if (toDevice) {
toDevice->mapPoints(&a, 1);
toDevice->mapPoints(&b, 1);
toDevice->mapPoints(&c, 1);
}
// make a new poly where we replace a and c by a 1-pixel wide edges orthog
// to edges ab and bc:
//
// before | after
// | b0
// b |
// |
// | a0 c0
// a c | a1 c1
//
// edges a0->b0 and b0->c0 are parallel to original edges a->b and b->c,
// respectively.
BezierVertex& a0 = verts[0];
BezierVertex& a1 = verts[1];
BezierVertex& b0 = verts[2];
BezierVertex& c0 = verts[3];
BezierVertex& c1 = verts[4];
SkVector ab = b;
ab -= a;
SkVector ac = c;
ac -= a;
SkVector cb = b;
cb -= c;
// We should have already handled degenerates
SkASSERT(ab.length() > 0 && cb.length() > 0);
ab.normalize();
SkVector abN;
abN.setOrthog(ab, SkVector::kLeft_Side);
if (abN.dot(ac) > 0) {
abN.negate();
}
cb.normalize();
SkVector cbN;
cbN.setOrthog(cb, SkVector::kLeft_Side);
if (cbN.dot(ac) < 0) {
cbN.negate();
}
a0.fPos = a;
a0.fPos += abN;
a1.fPos = a;
a1.fPos -= abN;
c0.fPos = c;
c0.fPos += cbN;
c1.fPos = c;
c1.fPos -= cbN;
intersect_lines(a0.fPos, abN, c0.fPos, cbN, &b0.fPos);
if (toSrc) {
toSrc->mapPointsWithStride(&verts[0].fPos, sizeof(BezierVertex), kQuadNumVertices);
}
}
int check_obstacle(struct _object *objs_l, int n_obj_l,
double *int_x, double *int_y,
double beam_x, double beam_y,
double dbeam_x, double dbeam_y,
double x1, double y1, double x2, double y2,
double offset)
{
int intersect = 0, i;
double dist, min_dist=0.0;
double closest_int_x=0.0, closest_int_y=0.0;
double a, b, c, lambda, h1, h2, discr, diameter;
double x1_minus_offset = x1 - offset, y1_minus_offset = y1 - offset,
x2_plus_offset = x2 + offset, y2_plus_offset = y2 + offset;
double temp1, temp2;
for (i = 0; i < n_obj_l; i++) {
if (objs_l[i].type == O_RECTANGLE && objs_l[i].status == 0 &&
/* rectangle */
((objs_l[i].x1 >= x1_minus_offset && objs_l[i].x1 <= x2_plus_offset &&
objs_l[i].y1 >= y1_minus_offset && objs_l[i].y1 <= y2_plus_offset) ||
(objs_l[i].x2 >= x1_minus_offset && objs_l[i].x2 <= x2_plus_offset &&
objs_l[i].y1 >= y1_minus_offset && objs_l[i].y1 <= y2_plus_offset) ||
(objs_l[i].x1 >= x1_minus_offset && objs_l[i].x1 <= x2_plus_offset &&
objs_l[i].y2 >= y1_minus_offset && objs_l[i].y2 <= y2_plus_offset) ||
(objs_l[i].x2 >= x1_minus_offset && objs_l[i].x2 <= x2_plus_offset &&
objs_l[i].y2 >= y1_minus_offset && objs_l[i].y2 <= y2_plus_offset))) {
if (dbeam_y > 0.0 &&
intersect_lines(int_x, int_y, objs_l[i].x1-offset,
objs_l[i].y1-offset,
objs_l[i].x2-objs_l[i].x1+(2.0*offset), 0.0,
beam_x, beam_y, dbeam_x, dbeam_y, 0) &&
*int_x >= objs_l[i].x1-offset && *int_x <= objs_l[i].x2+offset) {
temp1 = beam_x - *int_x;
temp2 = beam_y - *int_y;
dist = (temp1 * temp1) + (temp2 * temp2);
if (intersect == FALSE || dist < min_dist) {
min_dist = dist;
intersect = TRUE;
closest_int_x = *int_x;
closest_int_y = *int_y;
}
} else if (dbeam_y < 0.0 &&
intersect_lines(int_x, int_y, objs_l[i].x1-offset,
objs_l[i].y2+offset,
objs_l[i].x2-objs_l[i].x1+(2.0*offset), 0.0,
beam_x, beam_y, dbeam_x, dbeam_y, 0)
&& *int_x >= objs_l[i].x1-offset
&& *int_x <= objs_l[i].x2+offset) {
temp1 = beam_x - *int_x;
temp2 = beam_y - *int_y;
dist = (temp1 * temp1) + (temp2 * temp2);
if (intersect == FALSE || dist < min_dist) {
min_dist = dist;
intersect = TRUE;
closest_int_x = *int_x;
closest_int_y = *int_y;
}
}
if (dbeam_x > 0.0 &&
intersect_lines(int_x, int_y, objs_l[i].x1-offset,
objs_l[i].y1-offset,
0.0, objs_l[i].y2-objs_l[i].y1+(2.0*offset),
beam_x, beam_y, dbeam_x, dbeam_y, 1) &&
*int_y >= objs_l[i].y1-offset && *int_y <=
objs_l[i].y2+offset) {
temp1 = beam_x - *int_x;
temp2 = beam_y - *int_y;
dist = (temp1 * temp1) + (temp2 * temp2);
if (intersect == FALSE || dist < min_dist) {
min_dist = dist;
intersect = TRUE;
closest_int_x = *int_x;
closest_int_y = *int_y;
}
} else if (dbeam_x < 0.0 &&
intersect_lines(int_x, int_y, objs_l[i].x2+offset,
objs_l[i].y1-offset,
0.0, objs_l[i].y2-objs_l[i].y1+(2.0*offset),
beam_x, beam_y, dbeam_x, dbeam_y, 1)
&& *int_y >= objs_l[i].y1-offset
&& *int_y <= objs_l[i].y2+offset) {
temp1 = beam_x - *int_x;
temp2 = beam_y - *int_y;
dist = (temp1 * temp1) + (temp2 * temp2);
if (intersect == FALSE || dist < min_dist) {
min_dist = dist;
intersect = TRUE;
closest_int_x = *int_x;
closest_int_y = *int_y;
}
}
}
diameter = objs_l[i].diameter + offset;
if (objs_l[i].type == O_ROUND && objs_l[i].status == 0 && /* rectangle */
objs_l[i].x1 >= x1-diameter && objs_l[i].x1 <= x2+diameter &&
objs_l[i].y1 >= y1-diameter && objs_l[i].y1 <= y2+diameter) {
/* intersection circle with line */
a = (dbeam_x * dbeam_x) + (dbeam_y * dbeam_y);
b = (beam_x*dbeam_x) + (beam_y*dbeam_y)
- (dbeam_x*objs_l[i].x1) - (dbeam_y*objs_l[i].y1);
h1 = beam_x - objs_l[i].x1;
h2 = beam_y - objs_l[i].y1;
c = (h1 * h1) + (h2 * h2) - (diameter * diameter);
if (a != 0.0) {
discr = ((b*b) / (a*a)) - (c/a);
if (discr > 0.0) {
discr = sqrt(discr);
h1 = 0.0 - (b / a);
lambda = h1 - discr;
if (lambda < 0.0 && h1 + discr >= 0.0) {
lambda = 0.0;
fprintf(stderr,
"\nWarning: object %f %f in obst #%d?",beam_x, beam_y,i);
}
if (lambda >= 0.0) {
h1 = lambda * dbeam_x;
h2 = lambda * dbeam_y;
*int_x = beam_x + h1;
*int_y = beam_y + h2;
dist = (h1 * h1) + (h2 * h2);
if (intersect == FALSE || dist < min_dist) {
min_dist = dist;
intersect = TRUE;
closest_int_x = *int_x;
closest_int_y = *int_y;
}
}
}
}
}
}
if (intersect) {
*int_x = closest_int_x;
*int_y = closest_int_y;
}
return intersect;
}
