MSUStudentWork/ComputationalGeometry/6Ex/SCP.c

100 lines
No EOL
2.6 KiB
C

#include "SCP.h"
circle MEC(point * I, int ilen, point * N, int nlen) {
if (ilen != 0 && nlen < 3) {
point rnd = I[ilen - 1];
circle crcl = MEC(I, ilen - 1, N, nlen);
if (belongs(crcl, rnd)) return crcl;
else {
N[nlen++] = rnd;
return MEC(I, ilen - 1, N, nlen);
}
} else return primitive(N, nlen);
}
bool belongs(circle crcl, point p) {
if (powd(p.x - crcl.center.x) + powd(p.y - crcl.center.y) <= exp + powd(crcl.radius)) return true;
return false;
}
double powd(double number) {
return number * number;
}
circle primitive(point * N, int nlen) {
if (nlen == 3) {
for (int i = 0; i < 3; ++i) {
for (int j = i + 1; j < 3; ++j) {
circle crcl = centermass(N[i], N[j]);
bool all_inside = true;
for (int k = 0; k < 3; ++k) {
if (!belongs(crcl, N[k])) {
all_inside = false;
break;
}
}
if (all_inside) {
return crcl;
}
}
}
return byThreePoints(N);
} else if (nlen == 2) {
return centermass(N[0], N[1]);
} else if (nlen == 1) {
return (circle){N[0], 0};
} else {
return (circle){(point){0, 0}, 0};
}
}
circle centermass(point p1, point p2) {
return (circle){(point){(p1.x + p2.x) / 2, (p1.y + p2.y) / 2}, distance(p1, p2) / 2};
}
circle byThreePoints(point * warp) {
point center = getCenter(warp);
double radius;
center.x += warp[0].x, center.y += warp[0].y;
radius = distance(center, warp[0]);
return (circle){center, radius};
}
point getCenter(point * warp) {
double sqrt1, sqrt2, scalar;
point vec1 = (point){warp[1].x - warp[0].x, warp[1].y - warp[0].y};
point vec2 = (point){warp[2].x - warp[0].x, warp[2].y - warp[0].y};
sqrt1 = vec1.x * vec1.x + vec1.y * vec1.y;
sqrt2 = vec2.x * vec2.x + vec2.y * vec2.y;
scalar = (vec1.x * vec2.y - vec2.x * vec1.y) * 2;
return (point){.x=((vec2.y * sqrt1 - vec1.y * sqrt2) / scalar), \
.y=((vec1.x * sqrt2 - vec2.x * sqrt1) / scalar)};
}
double straightAngle(point p1, point p2) {
return (p1.y - p2.y) / (p1.x - p2.x);
}
double distance(point p1, point p2) {
return sqrt(powd(p1.x - p2.x) + powd(p1.y - p2.y));
}
void printCircle(circle crcl) {
printf("(x - %.4lf)^2 + (y - %.4lf)^2 = %.4lf^2\n\n", crcl.center.x, crcl.center.y, crcl.radius);
printf("Center of circle at point (%.2lf, %.2lf)\nRadius is %.2lf\n", crcl.center.x, crcl.center.y, crcl.radius);
}
int isCover(circle crcl, points pts) {
for (int i = 0; i < pts.length; ++i) {
if (!belongs(crcl, pts.array[i])) return i;
}
return pts.length;
}