diff --git a/libs/phys/source/engine_2d.cpp b/libs/phys/source/engine_2d.cpp
index 6733bc44..470deb5b 100644
--- a/libs/phys/source/engine_2d.cpp
+++ b/libs/phys/source/engine_2d.cpp
@@ -84,6 +84,82 @@ namespace psemek::phys2d
 			return c;
 		}
 
+		template <typename Points1, typename Normals1, typename Points2, typename Normals2>
+		std::optional<collision> convex_collision(Points1 const & points1, Normals1 const & normals1, Points2 const & points2, Normals2 const & normals2)
+		{
+			static constexpr float inf = std::numeric_limits<float>::infinity();
+
+			bool invert = false;
+			geom::point<float, 2> point{0.f, 0.f};
+			float penetration = -inf;
+			geom::vector<float, 2> normal{0.f, 0.f};
+
+			// Normals of 1st body against points of 2nd body
+			{
+				auto p = std::begin(points1);
+				auto n = std::begin(normals1);
+
+				for (; n != std::end(normals1); ++p, ++n)
+				{
+					float min = inf;
+					geom::point<float, 2> minp{0.f, 0.f};
+					for (auto const & p2 : points2)
+					{
+						float v = geom::dot(p2 - *p, *n);
+						if (v < min)
+						{
+							min = v;
+							minp = p2;
+						}
+					}
+
+					if (min > 0.f)
+						return std::nullopt;
+
+					if (min > penetration)
+					{
+						point = minp;
+						penetration = min;
+						normal = *n;
+					}
+				}
+			}
+
+			// Normals of 2nd body against points of 1st body
+			{
+				auto p = std::begin(points2);
+				auto n = std::begin(normals2);
+
+				for (; n != std::end(normals2); ++p, ++n)
+				{
+					float min = inf;
+					geom::point<float, 2> minp{0.f, 0.f};
+					for (auto const & p1 : points1)
+					{
+						float v = geom::dot(p1 - *p, *n);
+						if (v < min)
+						{
+							min = v;
+							minp = p1;
+						}
+					}
+
+					if (min > 0.f)
+						return std::nullopt;
+
+					if (min > penetration)
+					{
+						invert = true;
+						point = minp;
+						penetration = min;
+						normal = *n;
+					}
+				}
+			}
+
+			return collision{point - normal * penetration / 2.f, (invert ? 1.f : -1.f) * normal * penetration};
+		}
+
 		std::optional<collision> shape_collision(ball const & b1, static_state const & s1, ball const & b2, static_state const & s2)
 		{
 			auto const d = s2.position - s1.position;
@@ -244,60 +320,39 @@ namespace psemek::phys2d
 			float w2 = b2.width  / 2.f;
 			float h2 = b2.height / 2.f;
 
-			float dxx = geom::dot(ex1, ex2);
-			float dxy = geom::dot(ex1, ey2);
-			float dyx = geom::dot(ey1, ex2);
-			float dyy = geom::dot(ey1, ey2);
-
-			// SAT collision detector, hand-optimized for boxes
-
-			geom::vector<float, 2> normal{0.f, 0.f};
-			float penetration = -std::numeric_limits<float>::infinity();
-			geom::point<float, 2> point{0.f, 0.f};
-
-			auto side = [&](geom::vector<float, 2> const & n, geom::point<float, 2> const & a, float vx, float vy, geom::point<float, 2> const & c, geom::vector<float, 2> const & ex, geom::vector<float, 2> const & ey, bool invert)
+			geom::point<float, 2> points1[4] =
 			{
-				float vc = geom::dot((c - a), n);
-
-				float v = vc - std::abs(vx) - std::abs(vy);
-
-				if (v > penetration)
-				{
-					penetration = v;
-					point = c - geom::sign(vx) * ex - geom::sign(vy) * ey;
-					normal = invert ? -n : n;
-				}
+				s1.position - ex1 * w1 - ey1 * h1,
+				s1.position + ex1 * w1 - ey1 * h1,
+				s1.position + ex1 * w1 + ey1 * h1,
+				s1.position - ex1 * w1 + ey1 * h1,
 			};
 
-			// dot(n, c +/- ex +/- ey) = dot(n, c) +/- dot(n, ex) +/- dot(n, ey)
+			geom::vector<float, 2> normals1[4] =
+			{
+				-ey1,
+				ex1,
+				ey1,
+				-ex1
+			};
 
-			// box2 vs box1 +x
-			side(ex1, s1.position + ex1 * w1, dxx * w2, dxy * h2, s2.position, ex2 * w2, ey2 * h2, false);
-			if (penetration > 0.f) return std::nullopt;
-			// box2 vs box1 -x
-			side(-ex1, s1.position - ex1 * w1, -dxx * w2, -dxy * h2, s2.position, ex2 * w2, ey2 * h2, false);
-			if (penetration > 0.f) return std::nullopt;
-			// box2 vs box1 +y
-			side(ey1, s1.position + ey1 * h1, dyx * w2, dyy * h2, s2.position, ex2 * w2, ey2 * h2, false);
-			if (penetration > 0.f) return std::nullopt;
-			// box2 vs box1 -y
-			side(-ey1, s1.position - ey1 * h1, -dyx * w2, -dyy * h2, s2.position, ex2 * w2, ey2 * h2, false);
-			if (penetration > 0.f) return std::nullopt;
+			geom::point<float, 2> points2[4] =
+			{
+				s2.position - ex2 * w2 - ey2 * h2,
+				s2.position + ex2 * w2 - ey2 * h2,
+				s2.position + ex2 * w2 + ey2 * h2,
+				s2.position - ex2 * w2 + ey2 * h2,
+			};
 
-			// box1 vs box2 +x
-			side(ex2, s2.position + ex2 * w2, dxx * w1, dyx * h1, s1.position, ex1 * w1, ey1 * h1, true);
-			if (penetration > 0.f) return std::nullopt;
-			// box1 vs box2 -x
-			side(-ex2, s2.position - ex2 * w2, -dxx * w1, -dyx * h1, s1.position, ex1 * w1, ey1 * h1, true);
-			if (penetration > 0.f) return std::nullopt;
-			// box1 vs box2 +y
-			side(ey2, s2.position + ey2 * h2, dxy * w1, dyy * h1, s1.position, ex1 * w1, ey1 * h1, true);
-			if (penetration > 0.f) return std::nullopt;
-			// box1 vs box2 -y
-			side(-ey2, s2.position - ey2 * h2, -dxy * w1, -dyy * h1, s1.position, ex1 * w1, ey1 * h1, true);
-			if (penetration > 0.f) return std::nullopt;
+			geom::vector<float, 2> normals2[4] =
+			{
+				-ey2,
+				ex2,
+				ey2,
+				-ex2
+			};
 
-			return collision{point, -normal * penetration};
+			return convex_collision(points1, normals1, points2, normals2);
 		}
 
 	}