initial commit

include/geometry/aabb.hpp

@@ -0,0 +1,91 @@
+#pragma once
+
+#include "glm/glm.hpp"
+
+#include <limits>
+#include <algorithm>
+#include <span>
+#include <array>
+
+struct aabb
+{
+	using vector_type = glm::vec3;
+	using scalar_type = vector_type::value_type;
+	using index_type = vector_type::length_type;
+
+	static constexpr auto default_min = std::numeric_limits<scalar_type>::max();
+	static constexpr auto default_max =-std::numeric_limits<scalar_type>::max();
+
+	vector_type min { default_min, default_min, default_min };
+	vector_type max { default_max, default_max, default_max };
+
+	[[nodiscard]] vector_type size() const
+	{
+		return max - min;
+	}
+
+	[[nodiscard]] vector_type center() const
+	{
+		return min + 0.5f * size();
+	}
+
+	[[nodiscard]] vector_type closest_point_inside(const vector_type& point) const {
+		return {
+			std::clamp(point.x, min.x, max.x),
+			std::clamp(point.y, min.y, max.y),
+			std::clamp(point.z, min.z, max.z)
+		};
+	}
+
+	aabb& add_aabb(const aabb& other)
+	{
+		for (index_type i{}; i != min.length(); ++i)
+		{
+			min[i] = std::min(min[i], other.min[i]);
+			max[i] = std::max(max[i], other.max[i]);
+		}
+		return *this;
+	}
+
+	aabb& add_point(const auto& point)
+	{
+		for (index_type i{}; i != min.length(); ++i)
+		{
+			min[i] = std::min(min[i], point[i]);
+			max[i] = std::max(max[i], point[i]);
+		}
+		return *this;
+	}
+
+	template<typename T>
+	aabb& add_points(std::span<const T> points)
+	{
+		for (const auto& point : points)
+		{
+			add_point(point);
+		}
+        return *this;
+	}
+
+	aabb& join(const aabb& other)
+	{
+		min = glm::min(min, other.min);
+		max = glm::max(max, other.max);
+		return *this;
+	}
+
+	[[nodiscard]] aabb transformed(const glm::mat4x4& matrix) const
+    {
+		const auto vertices = std::array{
+			vector_type{ matrix * glm::vec4{ min.x, min.y, min.z, 1 } },
+			vector_type{ matrix * glm::vec4{ min.x, min.y, max.z, 1 } },
+			vector_type{ matrix * glm::vec4{ min.x, max.y, min.z, 1 } },
+			vector_type{ matrix * glm::vec4{ min.x, max.y, max.z, 1 } },
+			vector_type{ matrix * glm::vec4{ max.x, min.y, min.z, 1 } },
+			vector_type{ matrix * glm::vec4{ max.x, min.y, max.z, 1 } },
+			vector_type{ matrix * glm::vec4{ max.x, max.y, min.z, 1 } },
+			vector_type{ matrix * glm::vec4{ max.x, max.y, max.z, 1 } }
+		};
+		return aabb{}.add_points<vector_type>(vertices);
+	}
+};