1 files changed, 48 insertions, 0 deletions
diff --git a/lib/triangle.h b/lib/triangle.h
index 812bfab..abd697c 100644
--- a/lib/triangle.h
+++ b/lib/triangle.h
@@ -31,6 +31,13 @@ struct Triangle : public glm::vec<3, glm::vec<Dim, T, Q>> {
 		return glm::length(crossProduct(sideDifference(1), sideDifference(2))) / T {2};
 	}
 
+	[[nodiscard]] constexpr auto
+	area() const
+		requires(Dim == 2)
+	{
+		return std::abs((sideDifference(1).x * sideDifference(2).y) - (sideDifference(2).x * sideDifference(1).y)) / 2;
+	}
+
 	[[nodiscard]] constexpr Normal3D
 	normal() const
 		requires(Dim == 3)
@@ -38,6 +45,12 @@ struct Triangle : public glm::vec<3, glm::vec<Dim, T, Q>> {
 		return crossProduct(sideDifference(1), sideDifference(2));
 	}
 
+	[[nodiscard]] constexpr auto
+	height()
+	{
+		return (area() * 2) / ::distance(p(0), p(1));
+	}
+
 	[[nodiscard]] constexpr Normal3D
 	nnormal() const
 		requires(Dim == 3)
@@ -52,6 +65,12 @@ struct Triangle : public glm::vec<3, glm::vec<Dim, T, Q>> {
 	}
 
 	[[nodiscard]] constexpr auto
+	calcSideDifference(glm::length_t side) const
+	{
+		return calcDifference(p(side), p(0));
+	}
+
+	[[nodiscard]] constexpr auto
 	angle(glm::length_t corner) const
 	{
 		return Arc {P(corner), P(corner + 2), P(corner + 1)}.length();
@@ -71,6 +90,14 @@ struct Triangle : public glm::vec<3, glm::vec<Dim, T, Q>> {
 	}
 
 	[[nodiscard]] constexpr auto
+	isUp() const
+	{
+		const auto edgeAB = sideDifference(1);
+		const auto edgeAC = sideDifference(2);
+		return edgeAB.x * edgeAC.y >= edgeAB.y * edgeAC.x;
+	}
+
+	[[nodiscard]] constexpr auto
 	p(const glm::length_t idx) const
 	{
 		return Base::operator[](idx);
@@ -105,4 +132,25 @@ struct Triangle : public glm::vec<3, glm::vec<Dim, T, Q>> {
 	{
 		return begin() + 3;
 	}
+
+	[[nodiscard]]
+	constexpr auto
+	positionOnPlane(const glm::vec<2, T, Q> coord2d) const
+		requires(Dim == 3)
+	{
+		const auto edgeCrossProduct = crossProduct(calcSideDifference(1), calcSideDifference(2));
+		return coord2d
+				|| static_cast<T>(
+						((edgeCrossProduct.x * p(0).x) + (edgeCrossProduct.y * p(0).y) + (edgeCrossProduct.z * p(0).z)
+								- (edgeCrossProduct.x * coord2d.x) - (edgeCrossProduct.y * coord2d.y))
+						/ edgeCrossProduct.z);
+	}
+
+	[[nodiscard]]
+	constexpr bool
+	containsPoint(const GlobalPosition2D coord) const
+	{
+		return pointLeftOfOrOnLine(coord, p(0), p(1)) && pointLeftOfOrOnLine(coord, p(1), p(2))
+				&& pointLeftOfOrOnLine(coord, p(2), p(0));
+	}
 };