From a5812c02c8286244bd79c89aa2c1e787f3475eb6 Mon Sep 17 00:00:00 2001
From: lisyarus <lisyarus@gmail.com>
Date: Fri, 15 Mar 2024 23:27:24 +0300
Subject: [PATCH] Add generic cg::triangle_mesh convex body

---
 .../include/psemek/cg/body/triangle_mesh.hpp  | 64 +++++++++++++++++++
 1 file changed, 64 insertions(+)
 create mode 100644 libs/cg/include/psemek/cg/body/triangle_mesh.hpp

diff --git a/libs/cg/include/psemek/cg/body/triangle_mesh.hpp b/libs/cg/include/psemek/cg/body/triangle_mesh.hpp
new file mode 100644
index 00000000..c8630f36
--- /dev/null
+++ b/libs/cg/include/psemek/cg/body/triangle_mesh.hpp
@@ -0,0 +1,64 @@
+#pragma once
+
+#include <psemek/cg/body/body.hpp>
+#include <psemek/geom/simplex.hpp>
+
+#include <vector>
+#include <cstdint>
+
+namespace psemek::cg
+{
+	template <typename T, typename Index = std::uint32_t>
+	struct triangle_mesh
+	{
+		triangle_mesh() = default;
+		triangle_mesh(std::vector<geom::point<T, 3>> vertices, std::vector<geom::triangle<Index>> triangles);
+
+		std::vector<geom::point<T, 3>> vertices;
+		std::vector<geom::triangle<Index>> triangles;
+		std::vector<geom::segment<Index>> edges;
+		std::vector<geom::vector<T, 3>> edge_directions;
+	};
+
+	template <typename T, typename Index>
+	triangle_mesh<T, Index>::triangle_mesh(std::vector<geom::point<T, 3>> vertices, std::vector<geom::triangle<Index>> triangles)
+		: vertices(std::move(vertices))
+		, triangles(std::move(triangles))
+	{
+		for (auto const & t : this->triangles)
+		{
+			// Add each edge just once
+			if (t[0] < t[1]) edges.push_back({t[0], t[1]});
+			if (t[1] < t[2]) edges.push_back({t[1], t[2]});
+			if (t[2] < t[0]) edges.push_back({t[2], t[0]});
+		}
+
+		for (auto const & e : edges)
+			edge_directions.push_back(geom::normalized(this->vertices[e[1]] - this->vertices[e[0]]));
+	}
+
+	template <typename T, typename Index>
+	auto const & vertices(triangle_mesh<T, Index> const & m)
+	{
+		return m.vertices;
+	}
+
+	template <typename T, typename Index>
+	auto const & edges(triangle_mesh<T, Index> const & m)
+	{
+		return m.edges;
+	}
+
+	template <typename T, typename Index>
+	auto const & edge_directions(triangle_mesh<T, Index> const & m)
+	{
+		return m.edge_directions;
+	}
+
+	template <typename T, typename Index>
+	auto const & triangles(triangle_mesh<T, Index> const & m)
+	{
+		return m.triangles;
+	}
+
+}