1 files changed, 81 insertions, 0 deletions
diff --git a/game/terrain2.h b/game/terrain2.h
new file mode 100644
index 0000000..5539a50
--- /dev/null
+++ b/game/terrain2.h
@@ -0,0 +1,81 @@
+#pragma once
+
+#include "collections.h" // IWYU pragma: keep IterableCollection
+#include "ray.h"
+#include <OpenMesh/Core/Mesh/TriMesh_ArrayKernelT.hh>
+#include <filesystem>
+#include <glm/vec2.hpp>
+#include <optional>
+#include <thirdparty/openmesh/glmcompat.h>
+
+struct TerrainTraits : public OpenMesh::DefaultTraits {
+	FaceAttributes(OpenMesh::Attributes::Normal | OpenMesh::Attributes::Status);
+	EdgeAttributes(OpenMesh::Attributes::Status);
+	VertexAttributes(OpenMesh::Attributes::Normal | OpenMesh::Attributes::Status);
+	HalfedgeAttributes(OpenMesh::Attributes::Normal | OpenMesh::Attributes::Status);
+	using Point = glm::vec3;
+	using Normal = glm::vec3;
+};
+
+class TerrainMesh : public OpenMesh::TriMesh_ArrayKernelT<TerrainTraits> {
+public:
+	explicit TerrainMesh(const std::filesystem::path &);
+
+	struct PointFace {
+		// NOLINTNEXTLINE(hicpp-explicit-conversions)
+		PointFace(const glm::vec2 p) : point {p} { }
+
+		PointFace(const glm::vec2 p, FaceHandle face) : point {p}, _face {face} { }
+
+		PointFace(const glm::vec2 p, const TerrainMesh *);
+		PointFace(const glm::vec2 p, const TerrainMesh *, FaceHandle start);
+
+		const glm::vec2 point;
+		[[nodiscard]] FaceHandle face(const TerrainMesh *) const;
+		[[nodiscard]] FaceHandle face(const TerrainMesh *, FaceHandle start) const;
+
+		[[nodiscard]] bool
+		isLocated() const
+		{
+			return _face.is_valid();
+		}
+
+	private:
+		mutable FaceHandle _face {};
+	};
+
+	template<glm::length_t Dim> struct Triangle : public glm::vec<3, glm::vec<Dim, glm::vec2::value_type>> {
+		using base = glm::vec<3, glm::vec<Dim, glm::vec2::value_type>>;
+		using base::base;
+
+		template<IterableCollection Range> Triangle(const TerrainMesh * m, Range range)
+		{
+			assert(std::distance(range.begin(), range.end()) == 3);
+			std::transform(range.begin(), range.end(), &base::operator[](0), [m](auto vh) {
+				return m->point(vh);
+			});
+		}
+
+		glm::vec<Dim, glm::vec2::value_type>
+		operator*(glm::vec2 bari) const
+		{
+			const auto & t {*this};
+			return t[0] + ((t[1] - t[0]) * bari.x) + ((t[2] - t[1]) * bari.y);
+		}
+	};
+
+	[[nodiscard]] FaceHandle findPoint(glm::vec2) const;
+	[[nodiscard]] FaceHandle findPoint(glm::vec2, FaceHandle start) const;
+
+	[[nodiscard]] glm::vec3 positionAt(const PointFace &) const;
+	[[nodiscard]] std::optional<glm::vec3> intersectRay(const Ray &) const;
+	[[nodiscard]] std::optional<glm::vec3> intersectRay(const Ray &, FaceHandle start) const;
+
+	void walk(const PointFace & from, const glm::vec2 to, const std::function<void(FaceHandle)> & op) const;
+	void walkUntil(const PointFace & from, const glm::vec2 to, const std::function<bool(FaceHandle)> & op) const;
+
+protected:
+	[[nodiscard]] static bool triangleContainsPoint(const glm::vec2, const glm::vec2, const glm::vec2, const glm::vec2);
+	[[nodiscard]] bool triangleContainsPoint(const glm::vec2, FaceHandle) const;
+	[[nodiscard]] bool triangleContainsPoint(const glm::vec2, ConstFaceVertexIter) const;
+};