wip physicsutils

CMakeLists.txt

@@ -219,7 +219,6 @@ add_library(openc2e-core STATIC
 	src/parseException.cpp
 	src/partzorder.cpp
 	src/PathResolver.cpp
-	src/physics.cpp
 	src/PointerAgent.cpp
 	src/Port.cpp
 	src/prayManager.cpp

src/Map.cpp

@@ -23,6 +23,7 @@
 #include "MetaRoom.h"
 #include "Room.h"
 #include "creaturesException.h"
+#include "physicsUtils.h"
 
 #include <cassert>
 #include <iostream>
@@ -218,7 +219,7 @@ bool Map::collideLineWithRoomBoundaries(Point src, Point dest, std::shared_ptr<R
 		/*if (previousroom)
 			if (x[i].containsPoint(oldpoint)) continue; */
 
-		optional<Point> temppoint = Line::intersect(x[i], movement);
+		optional<Point> temppoint = physicsUtils::intersect(x[i], movement);
 		if (temppoint) {
 			//if (temppoint == src) return false; // for debug use: sneakily fail all movement between rooms
 

src/physics.h

@@ -52,8 +52,6 @@ class Line {
 	Point start, end;
 
   public:
-	void dump() const;
-
 	Line() {
 		start = Point(0, 0);
 		end = Point(1, 1);
@@ -64,16 +62,19 @@ class Line {
 		end = l.end;
 	}
 
-	Line(Point s, Point e);
+	Line(Point s, Point e) {
+		if (s.x > e.x)
+			std::swap(s, e);
+		start = s;
+		end = e;
+	}
 
 	Line& operator=(const Line& l) {
 		start = l.start;
 		end = l.end;
 		return *this;
 	}
 
-	static optional<Point> intersect(const Line& l1, const Line& l2);
-
 	bool isHorizontal() const { return start.y == end.y; }
 	bool isVertical() const { return start.x == end.x; }
 	float slope() const {

src/physicsUtils.h

@@ -0,0 +1,29 @@
+#pragma once
+
+#include "physics.h"
+
+namespace physicsUtils {
+
+optional<Point> intersect(const Line& l1, const Line& l2) {
+	auto denominator = (l2.getEnd().y - l2.getStart().y) * (l1.getEnd().x - l1.getStart().x) - (l2.getEnd().x - l2.getStart().x) * (l1.getEnd().y - l1.getStart().y);
+	if (std::fabs(denominator) < 0.00001) {
+		// lines are parallel, e.g. they either don't intersect or they overlap
+		return {};
+	}
+
+	auto a = (l2.getEnd().x - l2.getStart().x) * (l1.getStart().y - l2.getStart().y) - (l2.getEnd().y - l2.getStart().y) * (l1.getStart().x - l2.getStart().x);
+	auto b = (l1.getEnd().x - l1.getStart().x) * (l1.getStart().y - l2.getStart().y) - (l1.getEnd().y - l1.getStart().y) * (l1.getStart().x - l2.getStart().x);
+
+	auto ua = a / denominator;
+	auto ub = b / denominator;
+
+	if (ua >= 0 && ua <= 1 && ub >= 0 && ub <= 1) {
+		// intersected!
+		auto x = l1.getStart().x + ua * (l1.getEnd().x - l1.getStart().x);
+		auto y = l1.getStart().y + ua * (l1.getEnd().y - l1.getStart().y);
+		return Point(x, y);
+	}
+	return {};
+}
+
+} // namespace physicsUtils