1 files changed, 116 insertions, 0 deletions
diff --git a/test/geometry/circle.cpp b/test/geometry/circle.cpp
new file mode 100644
index 0000000..3d3d27d
--- /dev/null
+++ b/test/geometry/circle.cpp
@@ -0,0 +1,116 @@
+#include "../util.h"
+constexpr double EPS = 1e-6;
+#define ll double
+double gcd(double x, double /**/) {return x;} //hacky
+#include <geometry/formulas.cpp>
+#undef ll
+#include <geometry/circle.cpp>
+
+// Entfernung von Punkt p zur Geraden durch a-b. 2d und 3d
+double distToLine(pt a, pt b, pt p) {
+	return abs(cross(p - a, b - a)) / abs(b - a);
+}
+
+pt randomIntegerPT(ll range) {
+	return pt(Random::integer<ll>(-range, range), Random::integer<ll>(-range, range));
+}
+
+ll sq(ll x) {
+	return x*x;
+}
+
+int expectedCount(ll x1, ll y1, ll r1, ll x2, ll y2, ll r2) {
+	if (x1 == x2 && y1 == y2){
+		return r1 == r2 ? -1 : 0;
+	} else {
+		ll d = sq(x1 - x2) + sq(y1 - y2);
+
+		if (d > sq(r1 + r2) || d < sq(r1 - r2)) {
+			return 0;
+		} else if (d == sq(r1 + r2) || d == sq(r1 - r2)) {
+			return 1;
+		} else{
+			return 2;
+		}
+	}
+}
+
+void test_circleIntersection(ll range) {
+	int queries = 0;
+	for (int tries = 0; tries < 1'000'000; tries++) {
+		auto c1 = randomIntegerPT(range);
+		auto c2 = c1;
+		while (c1 == c2) c2 = randomIntegerPT(range);
+		double r1 = Random::integer<ll>(1, range);
+		double r2 = Random::integer<ll>(1, range);
+
+		auto got = circleIntersection(c1, r1, c2, r2);
+
+		if (sz(got) != expectedCount(real(c1), imag(c1), r1, real(c2), imag(c2), r2)) cerr << "error: wrong count" << FAIL;
+
+		for (int i = 0; i < sz(got); i++) {
+			for (int j = 0; j < i; j++) {
+				if (abs(got[i] - got[j]) < 1e-6) cerr << "error: identical" << FAIL;
+			}
+		}
+
+		for (auto p : got) {
+			if (float_error(abs(c1 - p), r1) > 1e-6) cerr << "error: 1" << FAIL;
+			if (float_error(abs(c2 - p), r2) > 1e-6) cerr << "error: 2" << FAIL;
+		}
+		queries += sz(got);
+	}
+	cerr << "tested circleIntersection: " << queries << endl;
+}
+
+void test_circleRayIntersection(ll range) {
+	int queries = 0;
+	for (int tries = 0; tries < 1'000'000; tries++) {
+		auto c = randomIntegerPT(range);
+		double r = Random::integer<ll>(1, range);
+
+		pt orig = randomIntegerPT(range);
+		pt dir = 0;
+		while (abs(dir) < 0.5) dir = randomIntegerPT(range);
+
+		auto got = circleRayIntersection(c, r, orig, dir);
+
+		double dist = distToLine(orig, orig + dir, c);
+		int lineIntersections = 0;
+		if (dist <= r) lineIntersections = 2;
+		if (abs(dist - r) < 1e-9) lineIntersections = 1;
+
+		int expected = 0;
+		if (abs(orig - c) < r) expected = 1; //starts inside
+		if (abs(orig - c) > r) { //starts outside
+			if (dot(dir, c - orig) >= 0) expected = lineIntersections;
+			else expected = 0;
+		}
+		if (abs(abs(orig - c) - r) < 1e-9) { //starts on circle
+			if (dot(dir, c - orig) >= 0) expected = lineIntersections;
+			else expected = 1;
+		}
+
+		if (sz(got) != expected) cerr << "error: wrong count" << FAIL;
+
+		for (int i = 0; i < sz(got); i++) {
+			for (int j = 0; j < i; j++) {
+				if (abs(got[i] - got[j]) < 1e-6) cerr << "error: identical" << FAIL;
+			}
+		}
+
+		for (auto p : got) {
+			if (float_error(abs(c - p), r) > 1e-6) cerr << "error: 1" << FAIL;
+			if (distToLine(orig, orig + dir, p) > 1e-6) cerr << "error: 2" << FAIL;
+		}
+		queries += sz(got);
+	}
+	cerr << "tested circleIntersection: " << queries << endl;
+}
+
+int main() {
+	test_circleIntersection(10);
+	test_circleIntersection(100);
+	test_circleRayIntersection(10);
+	test_circleRayIntersection(100);
+}