add the vec2_{mean,sort_cw} helper methods (c88ef297) · Commits · github_fork / Clip

core/graphics/geometry.cc

+30 −0

Original line number	Diff line number	Diff line
		@@ -59,6 +59,36 @@ vec2 vec2_from_deg(double deg) {
		return {cos(a), sin(a)};
		}

		vec2 vec2_mean(const vec2* v, size_t v_len) {
		vec2 m;

		for (size_t i = 0; i < v_len; ++i) {
		m = vec2_add(m, v[i]);
		}

		return vec2_mul(m, 1.0 / v_len);
		}

		void vec2_sort_cw(vec2* v, size_t v_len) {
		auto m = vec2_mean(v, v_len);

		std::sort(v, v + v_len, [&m] (const auto& a, const auto& b) {
		auto da = vec2_sub(a, m);
		auto db = vec2_sub(b, m);
		return atan2(db.y, db.x) < atan2(da.y, da.x);
		});
		}

		void vec2_sort_ccw(vec2* v, size_t v_len) {
		auto m = vec2_mean(v, v_len);

		std::sort(v, v + v_len, [&m] (const auto& a, const auto& b) {
		auto da = vec2_sub(a, m);
		auto db = vec2_sub(b, m);
		return atan2(da.y, da.x) < atan2(db.y, db.x);
		});
		}

		std::ostream& operator <<(std::ostream& os, const Point& p) {
		os << "Point(";
		os << p.x;

+15 −0

Original line number	Diff line number	Diff line
		@@ -45,6 +45,21 @@ vec2 vec2_mul(const vec2& v, double s);
		double vec2_dot(const vec2& a, const vec2& b);
		vec2 vec2_from_deg(double deg);

		/**
		* Find the mean value of a list of vectors
		*/
		vec2 vec2_mean(const vec2* v, size_t v_len);

		/**
		* Sort an array of vec2 objects in clockwise order
		*/
		void vec2_sort_cw(vec2* v, size_t v_len);

		/**
		* Sort an array of vec2 objects in counter-clockwise order
		*/
		void vec2_sort_ccw(vec2* v, size_t v_len);

		std::ostream& operator <<(std::ostream& os, const Point& c);
		std::ostream& operator <<(std::ostream& os, const Rectangle& c);