more tests

5 files changed, 117 insertions, 10 deletions

diff --git a/content/geometry/lines.cpp b/content/geometry/lines.cpp
index 95536a4..36de1db 100644
--- a/content/geometry/lines.cpp
+++ b/content/geometry/lines.cpp
@@ -1,10 +1,10 @@
 struct line {
-	double a, b, c; // ax + by + c = 0; vertikale Line: b = 0, sonst: b = 1
-	line(pt p, pt q) : a(-imag(q-p)), b(real(q-p)), c(cross({b, -a},p)) {}
+	double a, b, c; // ax + by + c = 0; vertikale Gerade: b = 0
+	line(pt p, pt q) : a(imag(p-q)), b(real(q-p)), c(cross({-b, a}, p)) {}
 };
 
-line pointsToLine(pt p1, pt p2) {
-	line l;
+line pointsToLine(pt p1, pt p2) { // vertikale Gerade: b = 1 oder b = 0
+	line l(0, 0);
 	if (abs(real(p1 - p2)) < EPS) {
 		l.a = 1; l.b = 0.0; l.c = -real(p1);
 	} else {
@@ -15,19 +15,19 @@ line pointsToLine(pt p1, pt p2) {
 	return l;
 }
 
-bool parallel(line l1, line l2) {
+bool parallel(line l1, line l2) { // braucht b in {0, 1}
 	return (abs(l1.a - l2.a) < EPS) && (abs(l1.b - l2.b) < EPS);
 }
 
-bool same(line l1, line l2) {
+bool same(line l1, line l2) { // braucht b in {0, 1}
 	return parallel(l1, l2) && (abs(l1.c - l2.c) < EPS);
 }
 
-bool intersect(line l1, line l2, pt& p) {
+bool intersect(line l1, line l2, pt& res) { // braucht b in {0, 1}
 	if (parallel(l1, l2)) return false;
 	double y, x = (l2.b * l1.c - l1.b * l2.c) / (l2.a * l1.b - l1.a * l2.b);
 	if (abs(l1.b) > EPS) y = -(l1.a * x + l1.c);
 	else y = -(l2.a * x + l2.c);
-	p = {x, y};
+	res = {x, y};
 	return true;
 }
diff --git a/content/geometry/linesAndSegments.cpp b/content/geometry/linesAndSegments.cpp
index 1e21cba..ddab554 100644
--- a/content/geometry/linesAndSegments.cpp
+++ b/content/geometry/linesAndSegments.cpp
@@ -5,7 +5,7 @@ bool pointOnLine(pt a, pt b, pt p) {
 
 // Test auf Linienschnitt zwischen a-b und c-d. (nicht identisch)
 bool lineIntersection(pt a, pt b, pt c, pt d) {
-	return abs(cross(a - b, c - d)) < EPS;
+	return abs(cross(a - b, c - d)) > EPS;
 }
 
 // Berechnet den Schnittpunkt der Graden a-b und c-d.
diff --git a/tcr.pdf b/tcr.pdf
index 649aa24..5ebfcb9 100644
--- a/tcr.pdf
+++ b/tcr.pdf
diff --git a/test/geometry/lines.cpp b/test/geometry/lines.cpp
new file mode 100644
index 0000000..7b1b99a
--- /dev/null
+++ b/test/geometry/lines.cpp
@@ -0,0 +1,107 @@
+#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/linesAndSegments.cpp>
+#include <geometry/lines.cpp>
+
+#include "../geometry.h"
+
+void stress_pointsToLine(ll range) {
+	ll queries = 0;
+	for (int tries = 0; tries < 100'000; tries++) {
+		auto [a, b] = Random::line(range);
+
+		line gotA(a, b);
+		if (real(a) != real(b)) {
+			gotA.a /= gotA.b;
+			gotA.c /= gotA.b;
+			gotA.b /= gotA.b;
+		} else {
+			gotA.c /= gotA.a;
+			gotA.a /= gotA.a;
+		}
+		line gotB = pointsToLine(a, b);
+
+		if (!same(gotA, gotB)) cerr << "error" << FAIL;
+		queries++;
+	}
+	cerr << "tested pointsToLine: " << queries << endl;
+}
+
+void stress_same(ll range) {
+	ll queries = 0;
+	for (int tries = 0; tries < 100'000; tries++) {
+		auto [a, b] = Random::line(range);
+		auto [c, d] = Random::line(range);
+
+		line lAB = pointsToLine(a, b);
+		line lCD = pointsToLine(c, d);
+
+		auto got = same(lAB, lCD);
+		auto expected = pointOnLine(a, b, c) && pointOnLine(a, b, d);
+
+		if (got != expected) cerr << "error" << FAIL;
+		queries++;
+	}
+	cerr << "tested same: " << queries << endl;
+}
+
+void stress_parallel(ll range) {
+	ll queries = 0;
+	for (int tries = 0; tries < 100'000; tries++) {
+		auto [a, b] = Random::line(range);
+		auto [c, d] = Random::line(range);
+
+		line lAB = pointsToLine(a, b);
+		line lCD = pointsToLine(c, d);
+
+		auto got = parallel(lAB, lCD);
+		auto expected = cross(b-a, d-c) == 0;
+
+		if (got != expected) cerr << "error" << FAIL;
+		queries++;
+	}
+	cerr << "tested parallel: " << queries << endl;
+}
+
+void stress_intersect(ll range) {
+	ll queries = 0;
+	for (int tries = 0; tries < 100'000; tries++) {
+		auto [a, b] = Random::line(range);
+		auto [c, d] = Random::line(range);
+
+		line lAB = pointsToLine(a, b);
+		line lCD = pointsToLine(c, d);
+
+		if (same(lAB, lCD)) continue;
+
+		pt gotPT;
+		auto got = intersect(lAB, lCD, gotPT);
+		auto expected = lineIntersection(a, b, c, d);
+
+		if (got != expected) cerr << "error: 1" << FAIL;
+		if (got) {
+			pt expectedPt = lineIntersection2(a, b, c, d);
+			if (float_error(real(gotPT), real(expectedPt)) > 1e-6) cerr << "error: 2" << FAIL;
+			if (float_error(imag(gotPT), imag(expectedPt)) > 1e-6) cerr << "error: 2" << FAIL;
+		}
+		queries++;
+	}
+	cerr << "tested intersect: " << queries << endl;
+}
+
+int main() {
+	stress_pointsToLine(100);
+	stress_pointsToLine(100'000);
+	stress_same(10);
+	stress_same(100);
+	stress_same(1'000'000'000);//no precision issue since this will alwas be false...
+	stress_parallel(10);
+	stress_parallel(100);
+	stress_parallel(1'000'000'000);
+	stress_intersect(100);
+	stress_intersect(1'000'000'000);
+}
diff --git a/test/geometry/linesAndSegments.cpp b/test/geometry/linesAndSegments.cpp
index 233546b..a2da3ba 100644
--- a/test/geometry/linesAndSegments.cpp
+++ b/test/geometry/linesAndSegments.cpp
@@ -30,7 +30,7 @@ void stress_lineIntersection(ll range) {
 		auto [c, d] = Random::line(range);
 		if (ccw(a, b, c) == 0 && ccw(a, b, d) == 0) continue;
 
-		bool expected = ccw(0, a-b, c-d) == 0;
+		bool expected = ccw(0, a-b, c-d) != 0;
 		bool got = lineIntersection(a, b, c, d);
 
 		if (got != expected) cerr << "error" << FAIL;