Fix retard rectangle-point collision check

src/engine/collision.cpp

@@ -109,47 +109,63 @@ namespace egn{
 		//If not in the rectangle, we can have 1 or 2 candidate edges to project onto. We want the closest one
 		//to the input point.
 		math::vec3<float> cand1, cand2;
-		if(r1 > r2){
-			cand1 = lineseg_point_proj(line_segment{l.point1, l.point4}, r);
-			if(r4 > r5){
-				//candidates be and bc
-				cand2 = lineseg_point_proj(line_segment{l.point1, l.point2}, r);
-			}else if(r6 < r5){
-				//candidates be and de
-				cand2 = lineseg_point_proj(line_segment{l.point3, l.point4}, r);
+
+		/*
+			now we divide the plane into a voronoi diagram where each region is closest
+			to either a line or a point on the rectangle. We use the r values calculated above
+			to determine which region the point lies within.
+
+			     a         b         c
+			             .         .
+			1      a1    .   b1    .   c1
+			             .         .
+			    - - - - -*---------*- - - - -
+			             |         |
+			2     a2     |   b2    |   c2
+			             |         |
+			    - - - - -*---------*- - - - -
+			             .         .
+			3     a3     .   b3    .   c3
+			             .         .
+		*/
+
+		if(r5 < r4){
+			//in column a
+			if(r2 < r1){
+				//a3
+				return l.point1;
+			}else if(r2 > r3){
+				//a1
+				return l.point2;
 			}else{
-				//candidate be
-				return cand1;
+				//a2
+				return lineseg_point_proj(line_segment{l.point1, l.point2}, r);
 			}
-		}else if(r3 < r2){
-			cand1 = lineseg_point_proj(line_segment{l.point2, l.point3}, r);
-			if(r4 > r5){
-				//candidates cd and bc
-				cand2 = lineseg_point_proj(line_segment{l.point1, l.point2}, r);
-			}else if(r6 < r5){
-				//candidates cd and de
-				cand2 = lineseg_point_proj(line_segment{l.point3, l.point4}, r);
+		}else if (r5 > r6){
+			//in column c
+			if(r2 < r1){
+				//c3
+				return l.point4;
+			}else if(r2 > r3){
+				//c1
+				return l.point3;
 			}else{
-				//candidate cd
-				return cand1;
+				//c2
+				return lineseg_point_proj(line_segment{l.point3, l.point4}, r);
 			}
-		}else if(r4 > r5){
-			//candidate bc
-			cand1 = lineseg_point_proj(line_segment{l.point1, l.point2}, r);
-			return cand1;
-		}else if(r6 < r5){
-			//candidate de
-			cand1 = lineseg_point_proj(line_segment{l.point3, l.point4}, r);
-			return cand1;
 		}else{
-			//point is inside rectangle
+			//in column b
+			if(r2 < r1){
+				//b3
+				return lineseg_point_proj(line_segment{l.point1, l.point4}, r);
+			}else if(r2 > r3){
+				//b1
+				return lineseg_point_proj(line_segment{l.point2, l.point3}, r);
+			}else{
+				//b2
 				return r;
 			}
-
-		//If we make it here, there are 2 candidate edges and we pick the closer one
-		math::vec3<float> diff1 = r - cand1;
-		math::vec3<float> diff2 = r - cand2;
-		return (diff1 * diff1) > (diff2 * diff2) ? cand1 : cand2;
+		}
 	}
 /*	bool check_collision(const collidable_iface& l, const collidable_iface& r, float epsilon){
 		return l.check_collision(r, epsilon);
@@ -259,7 +275,8 @@ namespace egn{
 
 		//find the nearest point on the rectangle to the newly created coplanar point and see if it's within
 		//epsilon of the original point
-		return math::magnitude(r - rectangle_point_coplanar_proj(l, projected_point)) <= epsilon;
+		math::vec3<float> proj_dist = r - rectangle_point_coplanar_proj(l, projected_point);
+		return (proj_dist * proj_dist) <= (epsilon * epsilon); //avoid square root
 	}
 	bool check_collision(const point& l, const point& r, float epsilon){
 		return math::fuzzy_eq(l, r, epsilon);

src/tests/collision/rectangle.cpp

@@ -0,0 +1,66 @@
+/**
+	This file is a part of our_dick
+	Copyright (C) 2021 rexy712
+
+	This program is free software: you can redistribute it and/or modify
+	it under the terms of the GNU Affero General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU Affero General Public License for more details.
+
+	You should have received a copy of the GNU Affero General Public License
+	along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "engine/collision.hpp"
+
+bool run_test(const egn::rectangle& l, const egn::point& r, bool desired_result){
+	if(egn::check_collision(l, r) != desired_result){
+		printf("FAIL\n");
+		return false;
+	}else{
+		printf("Succ\n");
+		return true;
+	}
+}
+
+struct testval{
+	egn::point p;
+	bool desres;
+};
+
+int main(){
+	egn::rectangle rect;
+	rect.point1 = {-1, -2, 1};
+	rect.point2 = {-1, 3, 1};
+	rect.point3 = {2, 3, 1};
+	rect.point4 = {2, -2, 1};
+
+	egn::point p;
+
+	testval tests[] = {
+		{{0,0, 1}, true},
+		{{1,1, 1}, true},
+		{{-1,3, 1}, true},
+		{{2,-2, 1}, true},
+		{{0,0, 0}, false},
+		{{0,0, -1}, false},
+		{{-1.1,0, 1}, false},
+		{{2.1,0, 1}, false},
+		{{0,-2.1, 1}, false},
+		{{0,3.1, 1}, false},
+		{{-1.1,3.1, 1}, false},
+		{{2.1,3.1, 1}, false},
+		{{2.1,-2.1, 1}, false},
+	};
+
+	for(const auto& [point,desres] : tests){
+		if(bool rv;rv = !run_test(rect, point, desres))
+			return rv;
+	}
+	return 0;
+}