include/fggl/math/types.hpp

@@ -18,19 +18,23 @@
 #include <tuple>
 #include <iostream>
 
-#include <glm/glm.hpp>
+#include "fggl/math/vector.hpp"
+
 #include <glm/ext/matrix_transform.hpp>
 #include <glm/gtc/quaternion.hpp>
 #include <glm/gtx/transform.hpp>
 #include <glm/gtx/euler_angles.hpp>
 #include <glm/gtx/quaternion.hpp>
 
+#include "fggl/math/fmath.hpp"
+#include "fggl/util/guid.hpp"
+
 #ifndef M_PI
-    #define M_PI 3.14159265358979323846
+	#define M_PI 3.14159265358979323846
 #endif
 
 #ifndef M_PI_2
-    #define M_PI_2 1.57079632679489661923
+	#define M_PI_2 1.57079632679489661923
 #endif
 
 namespace fggl::math {
@@ -42,36 +46,99 @@ namespace fggl::math {
 	using uint8 = std::uint8_t;
 
 	// math types (aliased for ease of use)
+
+	/**
+	 * A 4D floating-point vector.
+	 */
 	using vec4 = glm::vec4;
-	using vec4f = glm::vec4;
+
+
+	/**
+	 * A 4D signed integer vector.
+	 */
 	using vec4i = glm::ivec4;
-	using vec4ui = glm::ivec4;
 
+	/**
+	 * A 4D unsigned integer vector.
+	 */
+	using vec4ui = glm::uvec4;
+
+	/**
+	 * A 3D floating-point vector.
+	 */
 	using vec3 = glm::vec3;
+
+	/**
+	 * A 3D integer vector.
+	 */
 	using vec3i = glm::ivec3;
-	using vec3f = glm::vec3;
-	using vec3ui = glm::ivec3;
 
+	/**
+	 * A 3D unsigned integer vector.
+	 */
+	using vec3ui = glm::uvec3;
+
+	/**
+	 * A 2D floating-point vector
+	 */
 	using vec2 = glm::vec2;
-	using vec2f = glm::vec2;
+
+	/**
+	 * A 2D integer vector
+	 */
 	using vec2i = glm::ivec2;
-	using vec2ui = glm::ivec2;
 
+	/**
+	 * a 2D unsigned integer vector
+	 */
+	using vec2ui = glm::uvec2;
+
+	using vec2b = glm::bvec2;
+	using vec3b = glm::bvec3;
+	using vec4b = glm::bvec4;
+
+	/**
+	 * A 2x2 floating-point matrix.
+	 */
 	using mat2 = glm::mat2;
+
+	/**
+	 * A 3x3 floating-point matrix.
+	 */
 	using mat3 = glm::mat3;
+
+	/**
+	 * A 4x4 floating-point matrix.
+	 */
 	using mat4 = glm::mat4;
+
+	/**
+	 * A quaternion.
+	 */
 	using quat = glm::quat;
 
-	constexpr static const math::vec2 VEC2_ZERO {0.0F, 0.0F};
-	constexpr static const math::vec3 VEC3_ZERO {0.0F, 0.0F, 0.0F};
-	constexpr static const math::vec3 VEC3_ONES {1.0F, 1.0F, 1.0F};
+	constexpr static const math::mat4 IDENTITY_M4{1.0F};
+	constexpr static const math::quat IDENTITY_Q{1.0F, 0.0, 0.0, 0.0};
+
+	constexpr static const math::vec3 AXIS_X{1.0F, 0.0F, 0.0F};
+	constexpr static const math::vec3 AXIS_Y{0.0F, 1.0F, 0.0F};
+	constexpr static const math::vec3 AXIS_Z{0.0F, 0.0F, 1.0F};
 
-	constexpr static const math::mat4 IDENTITY_M4 {1.0F};
-	constexpr static const math::quat IDENTITY_Q {1.0F, 0.0, 0.0, 0.0};
+	constexpr auto minElm(vec3 a, vec3 b) -> vec3{
+		return {
+			a.x < b.x ? a.x : b.x,
+			a.y < b.y ? a.y : b.y,
+			a.z < b.z ? a.z : b.z
+		};
+	}
 
-	constexpr static const math::vec3 AXIS_X { 1.0F, 0.0F, 0.0F };
-	constexpr static const math::vec3 AXIS_Y { 0.0F, 1.0F, 0.0F };
-	constexpr static const math::vec3 AXIS_Z { 0.0F, 0.0F, 1.0F };
+	constexpr auto maxElm(vec3 a, vec3 b) -> vec3 {
+		return {
+			a.x > b.x ? a.x : b.x,
+			a.y > b.y ? a.y : b.y,
+			a.z > b.z ? a.z : b.z
+		};
+	}
 
 	// fastFloor from OpenSimplex2
 	inline int fastFloor(double x) {
@@ -79,27 +146,60 @@ namespace fggl::math {
 		return x < xi ? xi - 1 : xi;
 	}
 
-	inline float rescale_norm(float value, float min, float max) {
+	/**
+	 * Rescale a value between [min, max] into [0, 1].
+	 *
+	 * @param value the value to rescale
+	 * @param min the minimum value of the original range
+	 * @param max the maximum value of the original range
+	 * @return the rescaled value, [0, 1]
+	 */
+	constexpr float rescale_norm(float value, float min, float max) {
 		return (value - min) / (max - min);
 	}
 
-	inline float rescale_norm(float value, float min, float max, float newMin, float newMax) {
+	/**
+	 * Rescale a value between [min, max] into [newMin, newMax].
+	 *
+	 * @param value the value to rescale
+	 * @param min the minimum value of the original range
+	 * @param max the maximum value of the original range
+	 * @param newMin the new minimum value
+	 * @param newMax the new maximum value
+	 * @return the rescaled value, [newMin, newMax]
+	 */
+	constexpr float rescale_norm(float value, float min, float max, float newMin, float newMax) {
 		return newMin + ((value - min) * (newMax - newMin)) / (max - min);
 	}
 
-	inline float rescale_ndc(float value, float newMin, float newMax){
+	/**
+	 * Rescale a normalised device-coordinate value [-1, 1] into another range.
+	 *
+	 * @param value the value to rescale, [-1.0, 1.0]
+	 * @param newMin the new minimum value
+	 * @param newMax the new maximum value
+	 * @return the rescaled value, [newMin, newMax]
+	 */
+	constexpr float rescale_ndc(float value, float newMin, float newMax) {
 		return rescale_norm(value, -1, 1, newMin, newMax);
 	}
 
-	inline float rescale_01(float value, float newMin, float newMax){
+	/**
+	 * Rescale a normalised value [0, 1] into another range.
+	 *
+	 * @param value the value to rescale
+	 * @param newMin the new minimum value
+	 * @param newMax the new maximum value
+	 * @return the rescaled value, [newMin, newMax]
+	 */
+	constexpr float rescale_01(float value, float newMin, float newMax) {
 		return rescale_norm(value, 0, 1, newMin, newMax);
 	}
 
-	inline float recale_mean(float value, float avg, float max, float min) {
+	constexpr float recale_mean(float value, float avg, float max, float min) {
 		return (value - avg) / (max - min);
 	}
 
-
 	// reference vectors
 	constexpr vec3f UP{0.0f, 1.0f, 0.0f};
 	constexpr vec3f FORWARD{1.0f, 0.0f, 0.0f};
@@ -113,8 +213,14 @@ namespace fggl::math {
 		return modelMatrix(offset, glm::quat(eulerAngles));
 	}
 
+	// FIXME: we have multiple definitions of rays in the codebase!
+	struct Ray {
+		vec3 origin;
+		vec3 direction;
+	};
+
 	struct Transform {
-			constexpr static const char name[] = "Transform";
+			constexpr static const util::GUID guid = util::make_guid("Transform");
 
 			Transform() :
 				m_model(IDENTITY_M4),
@@ -182,14 +288,14 @@ namespace fggl::math {
 
 			[[nodiscard]]
 			inline mat4 local() const {
-				const glm::mat4 transformX = glm::rotate( math::IDENTITY_M4,glm::radians(m_euler.x), AXIS_X );
-				const glm::mat4 transformY = glm::rotate( math::IDENTITY_M4, glm::radians(m_euler.y), AXIS_Y );
-				const glm::mat4 transformZ = glm::rotate( math::IDENTITY_M4, glm::radians(m_euler.z), AXIS_Z );
+				const glm::mat4 transformX = glm::rotate(math::IDENTITY_M4, glm::radians(m_euler.x), AXIS_X);
+				const glm::mat4 transformY = glm::rotate(math::IDENTITY_M4, glm::radians(m_euler.y), AXIS_Y);
+				const glm::mat4 transformZ = glm::rotate(math::IDENTITY_M4, glm::radians(m_euler.z), AXIS_Z);
 
 				const auto rotation = transformY * transformX * transformZ;
 				return glm::translate(math::IDENTITY_M4, m_origin)
 					* rotation
-					* glm::scale( math::IDENTITY_M4, m_scale );
+					* glm::scale(math::IDENTITY_M4, m_scale);
 			}
 
 			[[nodiscard]]
@@ -197,7 +303,7 @@ namespace fggl::math {
 				return local();
 			}
 
-			inline void update(const math::mat4& parent) {
+			inline void update(const math::mat4 &parent) {
 				m_model = parent * local();
 			}
 
@@ -217,14 +323,14 @@ namespace fggl::math {
 			vec3 m_scale;
 	};
 
-}
+	inline math::mat4 calc_view_matrix(const Transform &transform) {
+		return glm::lookAt(transform.origin(), transform.origin() + transform.forward(), transform.up());
+	}
 
-// feels a bit strange to be doing this...
-namespace glm {
-	inline bool operator<(const vec3 &lhs, const vec3 &rhs) {
-		return std::tie(lhs.x, lhs.y, lhs.z)
-			< std::tie(rhs.x, rhs.y, rhs.z);
+	inline math::mat4 calc_view_matrix(const Transform &transform, vec3 target) {
+		return glm::lookAt(transform.origin(), target, transform.up());
 	}
+
 }
 
 #endif

include/fggl/math/vector.hpp

+/*
+ * This file is part of FGGL.
+ *
+ * FGGL is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any
+ * later version.
+ *
+ * FGGL is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License along with FGGL.
+ * If not, see <https://www.gnu.org/licenses/>.
+ */
+
+//
+// Created by webpigeon on 20/08/22.
+//
+
+#ifndef FGGL_MATH_VECTOR_HPP
+#define FGGL_MATH_VECTOR_HPP
+
+#include <ostream>
+#include <tuple>
+
+#define GLM_ENABLE_EXPERIMENTAL
+#include <glm/glm.hpp>
+
+namespace glm {
+	inline bool operator<(const vec2 &lhs, const vec2 &rhs) {
+		return std::tie(lhs.x, lhs.y)
+			< std::tie(rhs.x, rhs.y);
+	}
+
+	inline bool operator<(const vec3 &lhs, const vec3 &rhs) {
+		return std::tie(lhs.x, lhs.y, lhs.z)
+			< std::tie(rhs.x, rhs.y, rhs.z);
+	}
+
+	inline bool operator<(const vec4 &lhs, const vec4 &rhs) {
+		return std::tie(lhs.x, lhs.y, lhs.z, lhs.w)
+			< std::tie(rhs.x, rhs.y, rhs.z, rhs.w);
+	}
+
+	// output stream operators
+	inline std::ostream &operator<<(std::ostream &os, const vec2 &v) {
+		os << "(" << v.x << ", " << v.y << ")";
+		return os;
+	}
+
+	inline std::ostream &operator<<(std::ostream &os, const vec3 &v) {
+		os << "(" << v.x << ", " << v.y << "," << v.z << ")";
+		return os;
+	}
+
+	inline std::ostream &operator<<(std::ostream &os, const vec4 &v) {
+		os << "(" << v.x << ", " << v.y << "," << v.z << "," << v.w << ")";
+		return os;
+	}
+}
+
+#endif //FGGL_MATH_VECTOR_HPP

include/fggl/mesh/components.hpp

+/*
+ * This file is part of FGGL.
+ *
+ * FGGL is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any
+ * later version.
+ *
+ * FGGL is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License along with FGGL.
+ * If not, see <https://www.gnu.org/licenses/>.
+ */
+
+//
+// Created by webpigeon on 22/10/22.
+// FIXME HACKY IMPLEMENTATION DETAIL BECAUSE THE ASSET LOADING PIPELINE IS BAD
+//
+
+#include "fggl/mesh/mesh.hpp"
+
+#ifndef FGGL_MESH_COMPONENTS_HPP
+#define FGGL_MESH_COMPONENTS_HPP
+
+namespace fggl::mesh {
+
+	struct StaticMesh3D {
+		constexpr static const char name[] = "StaticMesh3D";
+		constexpr static const util::GUID guid = util::make_guid(name);
+
+		util::GUID meshReference;
+		Mesh3D mesh;
+		std::string pipeline;
+
+		inline StaticMesh3D() = default;
+		inline StaticMesh3D(const Mesh3D &aMesh, std::string aPipeline) :
+			mesh(aMesh), pipeline(std::move(aPipeline)) {}
+	};
+
+	struct StaticMultiMesh3D {
+		constexpr static const char name[] = "StaticMultiMesh3D";
+		constexpr static const util::GUID guid = util::make_guid(name);
+
+		util::GUID meshReference;
+		MultiMesh3D mesh;
+		std::string pipeline;
+
+		inline StaticMultiMesh3D() = default;
+		inline StaticMultiMesh3D(const MultiMesh3D &aMesh, std::string aPipeline) :
+			mesh(aMesh), pipeline(std::move(aPipeline)) {}
+	};
+
+}
+
+#endif //FGGL_MESH_COMPONENTS// _HPP

include/fggl/mesh/mesh.hpp

+/*
+ * This file is part of FGGL.
+ *
+ * FGGL is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any
+ * later version.
+ *
+ * FGGL is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License along with FGGL.
+ * If not, see <https://www.gnu.org/licenses/>.
+ */
+
+//
+// Created by webpigeon on 18/10/22.
+//
+
+#ifndef FGGL_MESH_MESH_HPP
+#define FGGL_MESH_MESH_HPP
+
+#include "fggl/math/types.hpp"
+#include "fggl/assets/types.hpp"
+
+#include <vector>
+#include <span>
+
+namespace fggl::mesh {
+
+	struct Vertex3D {
+		math::vec3 position;
+		math::vec3 normal;
+		math::vec3 colour{ 1.0F, 1.0F, 1.0F };
+		math::vec2 texPos{ NAN, NAN };
+
+		static Vertex3D from_pos(math::vec3 pos) {
+			return {
+				.position = pos,
+				.normal {NAN, NAN, NAN},
+				.colour {1.0F, 1.0F, 1.0F},
+				.texPos { pos.x, pos.z }
+			};
+		}
+	};
+
+	struct Vertex2D {
+		math::vec2 position;
+		math::vec2 colour;
+		math::vec2 texPos;
+	};
+
+	enum TextureType {
+		DIFFUSE, NORMAL
+	};
+
+	constexpr auto MISSING_TEXTURE = assets::AssetID::make(0);
+	struct Material {
+		std::string name;
+		math::vec3 ambient;
+		math::vec3 diffuse;
+		math::vec3 specular;
+		std::vector<assets::AssetID> diffuseTextures{};
+		std::vector<assets::AssetID> normalTextures{};
+		std::vector<assets::AssetID> specularTextures{};
+
+		inline assets::AssetID getPrimaryDiffuse() {
+			assert( !diffuseTextures.empty() );
+			return diffuseTextures.empty() ? MISSING_TEXTURE : diffuseTextures[0];
+		}
+
+		inline assets::AssetID getPrimaryNormals() {
+			assert( !normalTextures.empty() );
+			return normalTextures.empty() ? MISSING_TEXTURE : normalTextures[0];
+		}
+
+		inline assets::AssetID getPrimarySpecular() {
+			assert( !specularTextures.empty() );
+			return specularTextures.empty() ? MISSING_TEXTURE : specularTextures[0];
+		}
+	};
+
+	template<typename VertexFormat>
+	struct Mesh {
+		std::vector<VertexFormat> data;
+		std::vector<uint32_t> indices;
+		assets::AssetID material;
+
+		inline uint32_t append(const VertexFormat& vert) {
+			auto nextIdx = data.size();
+			data.push_back(vert);
+			return nextIdx;
+		}
+	};
+
+	template<typename MeshFormat>
+	struct MultiMesh {
+		std::vector<MeshFormat> meshes;
+		std::vector<assets::AssetID> materials;
+
+		MeshFormat& generate() {
+			return meshes.template emplace_back();
+		}
+	};
+
+	using Mesh2D = Mesh<Vertex2D>;
+	using MultiMesh2D = MultiMesh<Mesh2D>;
+
+	using Mesh3D = Mesh<Vertex3D>;
+	using MultiMesh3D = MultiMesh<Mesh3D>;
+
+}
+
+#endif //FGGL_MESH_MESH_HPP

include/fggl/modules/manager.hpp

+/*
+ * This file is part of FGGL.
+ *
+ * FGGL is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any
+ * later version.
+ *
+ * FGGL is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License along with FGGL.
+ * If not, see <https://www.gnu.org/licenses/>.
+ */
+
+//
+// Created by webpigeon on 27/06/22.
+//
+
+#ifndef FGGL_MODULES_MANAGER_HPP
+#define FGGL_MODULES_MANAGER_HPP
+
+#include "fggl/modules/module.hpp"
+#include "fggl/debug/logging.hpp"
+#include "fggl/ds/graph.hpp"
+
+#include <cassert>
+#include <queue>
+#include <vector>
+#include <map>
+#include <stack>
+#include <set>
+#include <iostream>
+
+namespace fggl::modules {
+
+	/**
+	 * Store and initialise modules present in the engine.
+	 *
+	 * This class is responsible for keeping track of which modules the library user has requested, and ensuring that
+	 * their dependencies are loaded in the correct order. Once the dependency graph has been built and instances
+	 * created, it is responsible for providing references to these initialised classes.
+	 */
+	class Manager {
+		public:
+			Manager() = default;
+
+			template<ServiceType T>
+			class Service {
+				public:
+					inline Service(Manager* manager) : m_manager(manager) {}
+
+					inline T* operator->() {
+						if ( m_ptr == nullptr ) {
+							m_ptr = m_manager->get<T>();
+						}
+						return m_ptr;
+					}
+
+				private:
+					Manager* m_manager;
+					std::shared_ptr<T> m_ptr;
+			};
+
+			inline void addVirtual(const Config &config) {
+				assert(!m_locked);
+
+				m_modules[config.name] = config;
+				for (const auto &service : config.provides) {
+					m_serviceProviders[service] = config.name;
+				}
+			}
+
+			template<ModuleType T>
+			void use() {
+				assert(!m_locked);
+
+				Config config{.name = T::name, .provides = {}, .depends = {}};
+				for (auto service : T::provides) {
+					config.provides.push_back(service);
+				}
+
+				for (auto service : T::depends) {
+					config.depends.push_back(service);
+				}
+				config.factory = T::factory;
+
+				addVirtual(config);
+			}
+
+            // FIXME this should be in cpp file
+			bool buildGraph() {
+				// resolve links between modules
+				for (auto &moduleItr : m_modules) {
+					if (moduleItr.second.depends.empty()) {
+						m_dependencies.addVertex(moduleItr.first);
+						continue;
+					}
+
+					for (auto &service : moduleItr.second.depends) {
+
+						auto provider = m_serviceProviders.find(service);
+						if (provider == m_serviceProviders.end()) {
+							debug::log(debug::Level::warning,
+									   "{} depends on {}, but nothing provides it",
+									   moduleItr.first,
+									   service.get());
+							// nothing can provide the service requested, setup is invalid.
+							return false;
+						}
+
+						m_dependencies.addEdge(moduleItr.first, provider->second);
+					}
+				}
+				return true;
+			}
+
+			template<ServiceType T>
+			T *get() const {
+				assert(m_locked);
+				return m_services.template get<T>();
+			}
+
+			template<ServiceType T>
+			Service<T> getLazy() const {
+				assert(m_locked);
+				return { this };
+			}
+
+            //FIXME this should be in cpp file!
+			void resolve() {
+				assert( !m_locked );
+				if (!buildGraph()) {
+					return;
+				}
+
+				std::queue<ModuleIdentifier> stack;
+				m_dependencies.getOrderRev(stack);
+
+				while (!stack.empty()) {
+					auto nextToInit = stack.front();
+					debug::log(debug::Level::info, "Initializing {}", nextToInit);
+
+					auto &module = m_modules.at(nextToInit);
+					if (module.factory != nullptr) {
+						for (auto &service : module.provides) {
+							bool result = module.factory(service, m_services);
+							if (!result) {
+								debug::log(debug::Level::warning,
+										   "{} could not create service {}",
+										   nextToInit,
+										   service.get());
+							}
+						}
+					} else {
+						debug::log(debug::Level::warning, "{} has no factory - skipping", nextToInit);
+					}
+					stack.pop();
+				}
+
+				debug::log(debug::Level::info, "engine boot complete");
+				m_locked = true;
+			}
+
+			inline Services& services() {
+				return m_services;
+			}
+
+		private:
+			bool m_locked = false;
+			Services m_services;
+			std::map<ModuleIdentifier, Config> m_modules;
+			ds::DirectedGraph<ModuleIdentifier> m_dependencies;
+			std::map<ServiceName, ModuleIdentifier> m_serviceProviders;
+
+	};
+
+} // namespace fggl::modules
+
+#endif //FGGL_MODULES_MANAGER_HPP

include/fggl/modules/module.hpp

+/*
+ * This file is part of FGGL.
+ *
+ * FGGL is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any
+ * later version.
+ *
+ * FGGL is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License along with FGGL.
+ * If not, see <https://www.gnu.org/licenses/>.
+ */
+
+//
+// Created by webpigeon on 27/06/22.
+//
+
+#ifndef FGGL_MODULES_MODULE_HPP
+#define FGGL_MODULES_MODULE_HPP
+
+#include <string>
+#include <vector>
+#include <functional>
+#include <map>
+#include <memory>
+
+#include "fggl/util/safety.hpp"
+#include "service.hpp"
+
+namespace fggl::modules {
+
+	template<typename T>
+	concept ModuleType = requires(T type) {
+		{ T::provides };
+		{ T::depends };
+	};
+
+	using ModuleIdentifier = std::string;
+
+	using ServiceFactory = std::function<bool(ServiceName , Services &)>;
+	struct Config {
+		ModuleIdentifier name;
+		std::vector<ServiceName> provides;
+		std::vector<ServiceName> depends;
+		ServiceFactory factory = nullptr;
+	};
+
+	class Module {
+		public:
+			virtual ~Module() = default;
+
+			// copying modules is bad
+			Module(const Module&) = delete;
+			Module& operator=(const Module&) = delete;
+
+			// moving modules is bad
+			Module(Module&&) = delete;
+			Module& operator=(Module&&) = delete;
+
+			virtual auto create(ServiceName, Services&) -> bool = 0;
+	};
+
+} // namespace fggl::modules
+
+#endif //FGGL_MODULES_MODULE_HPP

include/fggl/ecs3/module/module.hpp → include/fggl/modules/service.hpp

@@ -13,77 +13,64 @@
  */
 
 //
-// Created by webpigeon on 23/10/2021.
+// Created by webpigeon on 25/03/23.
 //
 
-#ifndef FGGL_ECS3_MODULE_MODULE_HPP
-#define FGGL_ECS3_MODULE_MODULE_HPP
+#ifndef FGGL_MODULES_SERVICE_HPP
+#define FGGL_MODULES_SERVICE_HPP
 
-#include <string>
 #include <map>
 #include <memory>
 
-#include <fggl/ecs3/types.hpp>
+#include "fggl/util/safety.hpp"
 
-namespace fggl::ecs3 {
+namespace fggl::modules {
 
-	class Module {
-		public:
-			virtual ~Module() = default;
-
-			[[nodiscard]] virtual std::string name() const = 0;
-
-			virtual void onLoad(ModuleManager &manager, TypeRegistry &tr) {};
+	using ServiceName = util::OpaqueName<std::string_view, struct ModuleServiceTag>;
+	constexpr ServiceName make_service(const std::string_view name) {
+		return ServiceName::make(name);
+	}
 
-			virtual void onUpdate();
-			virtual void onFrameStart();
-			virtual void onFrameEnd();
+	template<typename T>
+	concept ServiceType = requires(T* type) {
+		{ T::service };
 	};
 
-	class ModuleManager {
-		public:
-			explicit ModuleManager(TypeRegistry &types) : m_types(types), m_modules() {}
-
-			~ModuleManager() = default;
-
-			template<typename C, typename... Args>
-			std::shared_ptr<C> load(Args &... args) {
-				auto ptr = std::make_shared<C>(args...);
-				m_modules[ptr->name()] = ptr;
+	template<typename T, typename U>
+	concept Derived = std::is_base_of<U, T>::value;
 
-				ptr->onLoad(*this, m_types);
-				//spdlog::info("loaded ECS module: {}", ptr->name());
-				return ptr;
-			}
-
-			template<typename C>
-			void onAdd(const callback_t &cb) {
-				m_types.callbackAdd(Component<C>::typeID(), cb);
+	class Services {
+		public:
+			template<ServiceType Svc, Derived<Svc> Impl, typename ...Args>
+			void bind(Args... args) {
+				m_services[Svc::service] = std::make_shared<Impl>(args...);
 			}
 
-			void onUpdate() {
-				for (auto &[id, ptr] : m_modules) {
-					ptr->onUpdate();
-				}
+			template<ServiceType Svc, typename ...Args>
+			Svc *create(Args... args) {
+				auto svc = std::make_shared<Svc>(args...);
+				m_services[Svc::service] = svc;
+				return svc.get();
 			}
 
-			void onFrameStart() {
-				for (auto &[id, ptr] : m_modules) {
-					ptr->onFrameStart();
-				}
+			template<ServiceType Svc>
+			void provide(std::shared_ptr<Svc> service) {
+				m_services[Svc::service] = service;
 			}
 
-			void onFrameEnd() {
-				for (auto &[id, ptr] : m_modules) {
-					ptr->onFrameEnd();
-				}
+			template<ServiceType S>
+			S *get() const {
+				auto serviceWrapper = m_services.at(S::service);
+				auto ptr = std::static_pointer_cast<S>(serviceWrapper);
+				return ptr.get();
 			}
 
 		private:
-			TypeRegistry &m_types;
-			std::map<std::string, std::shared_ptr<Module>> m_modules;
+			std::map<ServiceName, std::shared_ptr<void>> m_services;
 	};
 
-}
+} // namespace fggl::modules
+
+
 
-#endif //FGGL_ECS3_MODULE_MODULE_HPP
+#endif //FGGL_MODULES_SERVICE_HPP

include/fggl/phys/callbacks.hpp

@@ -21,22 +21,23 @@
 
 #include <functional>
 #include <unordered_set>
+#include "fggl/entity/entity.hpp"
 
 namespace fggl::phys {
 
-	using CollisionCB = std::function<void(ecs3::entity_t, ecs3::entity_t)>;
+	using CollisionCB = std::function<void(entity::EntityID, entity::EntityID)>;
 
 	struct CollisionCallbacks {
-		constexpr static const char* name = "phys::Callbacks";
+		constexpr static const char *name = "phys::Callbacks";
 		CollisionCB onEnter = nullptr;
 		CollisionCB onExit = nullptr;
 		CollisionCB onStay = nullptr;
 	};
 
 	struct CollisionCache {
-		constexpr static const char* name = "phys::Cache";
-		std::unordered_set<ecs3::entity_t> collisions;
-		std::unordered_set<ecs3::entity_t> lastFrame;
+		constexpr static const char *name = "phys::Cache";
+		std::unordered_set<entity::EntityID> collisions;
+		std::unordered_set<entity::EntityID> lastFrame;
 	};
 
 } // namespace fggl::phys

include/fggl/phys/null.hpp

+/*
+ * This file is part of FGGL.
+ *
+ * FGGL is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any
+ * later version.
+ *
+ * FGGL is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License along with FGGL.
+ * If not, see <https://www.gnu.org/licenses/>.
+ */
+
+//
+// Created by webpigeon on 20/08/22.
+//
+
+#ifndef FGGL_PHYS_NULL_HPP
+#define FGGL_PHYS_NULL_HPP
+
+#include "fggl/phys/types.hpp"
+#include "fggl/phys/service.hpp"
+
+namespace fggl::phys {
+
+	inline void build_noop(const entity::ComponentSpec & /*config*/,
+						   entity::EntityManager &manager,
+						   const entity::EntityID &entity,
+						   modules::Services &/*services*/) {
+		manager.add<fggl::phys::RigidBody>(entity);
+		manager.add<fggl::phys::Dynamics>(entity);
+	}
+
+	class NullPhysicsEngine : public PhysicsEngine {
+		public:
+			inline void step() override {}
+
+			void setDebugDraw(bool /* enable */) override {}
+
+			inline std::vector<ContactPoint> scanCollisions(entity::EntityID /*entity*/) override {
+				return {};
+			}
+
+			inline entity::EntityID raycast(math::vec3 /*from*/, math::vec3 /*to*/) override {
+				return entity::INVALID;
+			}
+
+			inline std::vector<entity::EntityID> raycastAll(math::vec3 /*from*/, math::vec3 /*to*/) override {
+				return {};
+			}
+
+			inline std::vector<entity::EntityID> sweep(PhyShape & /*shape*/,
+													   math::Transform & /*from*/,
+													   math::Transform & /*to*/) override {
+				return {};
+			}
+	};
+
+	class NullPhysicsProvider : public PhysicsProvider {
+		public:
+			virtual ~NullPhysicsProvider() = default;
+
+			inline PhysicsEngine *create(entity::EntityManager * /*entityManager*/,
+										 entity::EntityFactory *factory) override {
+				factory->bind(util::make_guid("phys::Body"), build_noop);
+				return new NullPhysicsEngine();
+			}
+	};
+
+	struct NullPhysics {
+		constexpr static const char *name = "fggl::phys::null";
+		constexpr static const std::array<modules::ServiceName, 1> provides = {
+			phys::PhysicsProvider::service
+		};
+		constexpr static const std::array<modules::ServiceName, 1> depends = {
+			entity::EntityFactory::service
+		};
+		static bool factory(modules::ServiceName serviceName, modules::Services &serviceManager);
+	};
+
+} // namespace fggl::phys
+
+#endif //FGGL_PHYS_NULL_HPP

include/fggl/phys/service.hpp

+/*
+ * This file is part of FGGL.
+ *
+ * FGGL is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any
+ * later version.
+ *
+ * FGGL is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License along with FGGL.
+ * If not, see <https://www.gnu.org/licenses/>.
+ */
+
+//
+// Created by webpigeon on 01/08/22.
+//
+
+#ifndef FGGL_PHYS_SERVICE_HPP
+#define FGGL_PHYS_SERVICE_HPP
+
+#include "fggl/modules/module.hpp"
+#include "fggl/entity/module.hpp"
+#include "fggl/phys/types.hpp"
+
+namespace fggl::phys {
+
+	class PhysicsProvider {
+		public:
+			constexpr static const auto service = modules::make_service("fggl::phys::service");
+			virtual ~PhysicsProvider() = default;
+			virtual PhysicsEngine *create(entity::EntityManager *entityManager, entity::EntityFactory *factory) = 0;
+	};
+
+}
+
+#endif //FGGL_PHYS_SERVICE_HPP

include/fggl/phys/types.hpp

@@ -19,6 +19,7 @@
 #ifndef FGGL_PHYS_TYPES_HPP
 #define FGGL_PHYS_TYPES_HPP
 
+#include "fggl/math/types.hpp"
 #include "fggl/phys/callbacks.hpp"
 
 namespace fggl::phys {
@@ -27,9 +28,9 @@ namespace fggl::phys {
 	constexpr math::vec3 UNIT_EXTENTS{0.5F, 0.5F, 0.5F};
 
 	enum class ShapeType {
-			UNSET,
-			BOX,
-			SPHERE
+		UNSET,
+		BOX,
+		SPHERE
 	};
 
 	struct PhyShape {
@@ -41,22 +42,24 @@ namespace fggl::phys {
 
 	struct Box : public PhyShape {
 		math::vec3 extents;
+
 		explicit inline Box(math::vec3 ext) : PhyShape(ShapeType::BOX), extents(ext) {}
 	};
 
 	struct Sphere : public PhyShape {
 		float radius = 1.0F;
+
 		explicit inline Sphere(float rad) : PhyShape(ShapeType::SPHERE), radius(rad) {}
 	};
 
 	enum class BodyType {
-			STATIC, KINEMATIC, DYNAMIC
+		STATIC, KINEMATIC, DYNAMIC
 	};
 
 	struct RigidBody {
-		constexpr static const char* name = "phys::Body";
+		constexpr static const char *name = "phys::Body";
 		float mass = MASS_DEFAULT;
-		PhyShape* shape = nullptr;
+		PhyShape *shape = nullptr;
 		BodyType type = BodyType::DYNAMIC;
 
 		[[nodiscard]]
@@ -66,13 +69,13 @@ namespace fggl::phys {
 	};
 
 	struct Dynamics {
-		constexpr static const char* name = "phys::Dynamics";
+		constexpr static const char *name = "phys::Dynamics";
 		math::vec3 force = math::VEC3_ZERO;
 	};
 
 	struct ContactPoint {
-		ecs3::entity_t entityA;
-		ecs3::entity_t entityB;
+		entity::EntityID entityA;
+		entity::EntityID entityB;
 		math::vec3 localA;
 		math::vec3 localB;
 		math::vec3 normal;
@@ -97,19 +100,30 @@ namespace fggl::phys {
 			virtual ~PhysicsEngine() = default;
 
 			// no copy and no move
-			PhysicsEngine(PhysicsEngine&) = delete;
-			PhysicsEngine(PhysicsEngine&&) = delete;
-			PhysicsEngine& operator=(PhysicsEngine&) = delete;
-			PhysicsEngine& operator=(PhysicsEngine&&) = delete;
+			PhysicsEngine(PhysicsEngine &) = delete;
+			PhysicsEngine(PhysicsEngine &&) = delete;
+			PhysicsEngine &operator=(PhysicsEngine &) = delete;
+			PhysicsEngine &operator=(PhysicsEngine &&) = delete;
 
 			// query methods (first cut - unstable APIs)
-			virtual std::vector<ContactPoint> scanCollisions(ecs3::entity_t entity) = 0;
-			virtual ecs3::entity_t raycast(math::vec3 from, math::vec3 to) = 0;
-			virtual std::vector<ecs3::entity_t> raycastAll(math::vec3 from, math::vec3 to) = 0;
-			virtual std::vector<ecs3::entity_t> sweep(PhyShape& shape, math::Transform& from, math::Transform& to) = 0;
+			virtual std::vector<ContactPoint> scanCollisions(entity::EntityID entity) = 0;
+
+			virtual entity::EntityID raycast(math::vec3 from, math::vec3 to) = 0;
+
+			inline entity::EntityID raycast(math::Ray ray, float maxDist = 1000.0F) {
+				return raycast(ray.origin, ray.origin + ray.direction * maxDist);
+			}
+
+			virtual std::vector<entity::EntityID> raycastAll(math::vec3 from, math::vec3 to) = 0;
+			virtual std::vector<entity::EntityID> sweep(PhyShape &shape,
+														math::Transform &from,
+														math::Transform &to) = 0;
 
 			// update
 			virtual void step() = 0;
+
+			// debug
+			virtual void setDebugDraw(bool enable) = 0;
 	};
 
 } // namespace fggl::phys

include/fggl/platform/fallback/file.hpp

+/*
+ * This file is part of FGGL.
+ *
+ * FGGL is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any
+ * later version.
+ *
+ * FGGL is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License along with FGGL.
+ * If not, see <https://www.gnu.org/licenses/>.
+ */
+
+//
+// Created by webpigeon on 19/09/22.
+//
+
+#ifndef FGGL_PLATFORM_FALLBACK_FILE_HPP
+#define FGGL_PLATFORM_FALLBACK_FILE_HPP
+
+#include <cstdio>
+#include <cassert>
+
+namespace fggl::platform {
+
+	class File {
+		public:
+			inline File(FILE* filePtr) : m_handle(filePtr) {
+				assert(filePtr != nullptr);
+			}
+
+			inline ~File() {
+				release();
+			}
+
+			template<typename T>
+			inline void write(const T* dataPtr) {
+				assert( m_handle != nullptr );
+				int status = fwrite(dataPtr, sizeof(T), 1, m_handle );
+				assert( status == 1);
+			}
+
+			template<typename T>
+			inline void writeArr(const T* dataPtr, std::size_t numElms) {
+				assert( m_handle != nullptr);
+				int status = fwrite(dataPtr, sizeof(T), numElms, m_handle );
+				assert( status == 1);
+			}
+
+		private:
+			std::FILE* m_handle;
+
+			inline void release() {
+				if ( m_handle != NULL) {
+					fclose(m_handle);
+				}
+			}
+	};
+
+} // namespace fggl::platform
+
+#endif //FGGL_PLATFORM_FALLBACK_FILE_HPP

include/fggl/platform/fallback/paths.hpp

+/*
+ * This file is part of FGGL.
+ *
+ * FGGL is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any
+ * later version.
+ *
+ * FGGL is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License along with FGGL.
+ * If not, see <https://www.gnu.org/licenses/>.
+ */
+
+//
+// Low-Level Linux-specific path management
+// Created by webpigeon on 23/06/22.
+// see https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html
+//
+
+#ifndef FGGL_PLATFORM_FALLBACK_PATHS_HPP
+#define FGGL_PLATFORM_FALLBACK_PATHS_HPP
+
+#include "fggl/platform/paths.hpp"
+
+#include <filesystem>
+#include <array>
+
+#include <vector>
+
+namespace fggl::platform {
+
+	/**
+	 * The environment variable used for containing user configurations.
+	 *
+	 * The directory mentioned by this environment variable should be read/writeable.
+	 * The directory should be used for storing user-editable configuration options (eg. preferences).
+	 */
+	constexpr const char *ENV_USER_CONFIG = "FGGL_CONFIG_HOME";
+
+	/**
+	 * Fallback user configuration directory.
+	 *
+	 * Default user configuration directory if none is set by the environment variable.
+	 */
+	constexpr const char *DEFAULT_USER_CONFIG = "user_config";
+
+	/**
+	 * The environment variable used for containing engine data.
+	 *
+	 * This directory is used for storing persistent user data and therefore should be read/writable.
+	 * The directory should be used for storing user-modifiable state (eg, save files) or downloaded modifications.
+	 */
+	constexpr const char *ENV_USER_DATA = "FGGL_DATA_HOME";
+
+	/**
+	 * Fallback user data directory.
+	 *
+	 * Default user data directory if none is set by the environment variable.
+	 */
+	constexpr const char *DEFAULT_USER_DATA = "user_data";
+
+	/**
+	 * The environment variable used for containing semi-persistent user data.
+	 *
+	 * The application should be able to expect this directory to exist while the application is running, but otherwise
+	 * cannot expect the data to be persistent. It MAY be persistent but the application should not rely on this.
+	 * It should be used for resources which can be re-generated if needed, but can be useful if already present.
+	 */
+	constexpr const char *ENV_USER_CACHE = "FGGL_CACHE_HOME";
+
+	struct EnginePaths {
+		std::filesystem::path userConfig;
+		std::filesystem::path userData;
+		std::filesystem::path userCache;
+	};
+
+	/**
+	 * Fallback implementation of calc engine paths.
+	 *
+	 * For operating systems we don't know about, this simply uses the environment variables defined above and some
+	 * sane defaults to construct the paths used to locate our data and user configuration.
+	 *
+	 * @param base an application-unique string used to construct the paths.
+	 * @return the generated paths, for use with the rest of the engine.
+	 */
+	EnginePaths calc_engine_paths(const char *base);
+
+	// search routines for finding data and configuration files
+	std::filesystem::path locate_data(const EnginePaths &paths, const std::filesystem::path &relPath);
+	std::filesystem::path locate_config(const EnginePaths &paths, const std::filesystem::path &relPath);
+	std::filesystem::path locate_cache(const EnginePaths &paths, const std::filesystem::path &relPath);
+
+}
+
+#endif //FGGL_PLATFORM_FALLBACK_PATHS_HPP

include/fggl/platform/linux/paths.hpp

+/*
+ * This file is part of FGGL.
+ *
+ * FGGL is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any
+ * later version.
+ *
+ * FGGL is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License along with FGGL.
+ * If not, see <https://www.gnu.org/licenses/>.
+ */
+
+//
+// Low-Level Linux-specific path management
+// Created by webpigeon on 23/06/22.
+// see https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html
+//
+
+#ifndef FGGL_PLATFORM_LINUX_PATHS_HPP
+#define FGGL_PLATFORM_LINUX_PATHS_HPP
+
+#include "fggl/platform/paths.hpp"
+
+#include <filesystem>
+#include <array>
+
+#include <vector>
+
+namespace fggl::platform {
+
+	constexpr const char *ENV_USER_CONFIG = "XDG_CONFIG_HOME";
+	constexpr const char *ENV_USER_DATA = "XDG_DATA_HOME";
+	constexpr const char *ENV_USER_CACHE = "XDG_CACHE_HOME";
+
+	constexpr const char *ENV_DATA_DIRS = "XDG_DATA_DIRS";
+	constexpr const char *ENV_CONFIG_DIRS = "XDG_CONFIG_DIRS";
+
+	// fallback user paths defined in the XDG spec
+	constexpr const char *DEFAULT_USER_CONFIG = "~/.config";
+	constexpr const char *DEFAULT_USER_DATA = "~/.local/share";
+	constexpr const char *DEFAULT_USER_CACHE = "~/.cache";
+
+	// fallback search paths defined in the XDG spec
+	constexpr const std::array<const char *, 2> DEFAULT_DATA_DIRS = {"/usr/local/share/", "/usr/share/"};
+	constexpr const std::array<const char *, 1> DEFAULT_CONFIG_DIRS = {"/etc/xdg"};
+
+	struct EnginePaths {
+		std::filesystem::path userConfig;
+		std::filesystem::path userData;
+		std::filesystem::path userCache;
+		std::vector<std::filesystem::path> dataDirs;
+		std::vector<std::filesystem::path> configDirs;
+	};
+
+	EnginePaths calc_engine_paths(const char *base);
+
+	// search routines for finding data and configuration files
+	std::filesystem::path locate_data(const EnginePaths &paths, const std::filesystem::path &relPath);
+	std::filesystem::path locate_config(const EnginePaths &paths, const std::filesystem::path &relPath);
+	std::filesystem::path locate_cache(const EnginePaths &paths, const std::filesystem::path &relPath);
+
+}
+
+#endif //FGGL_PLATFORM_LINUX_PATHS_HPP

include/fggl/platform/paths.hpp

+/*
+ * This file is part of FGGL.
+ *
+ * FGGL is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any
+ * later version.
+ *
+ * FGGL is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License along with FGGL.
+ * If not, see <https://www.gnu.org/licenses/>.
+ */
+
+//
+// Created by webpigeon on 26/06/22.
+//
+
+#ifndef FGGL_PLATFORM_PATHS_HPP
+#define FGGL_PLATFORM_PATHS_HPP
+
+#include <filesystem>
+#include <vector>
+
+#ifdef __linux__
+	#define FGGL_PLATFORM_PATHS linux
+	#include "fggl/platform/linux/paths.hpp"
+#else
+	#define FGGL_PLATFORM_PATHS fallback
+	#include "fggl/platform/fallback/paths.hpp"
+#endif
+
+#endif //FGGL_PLATFORM_PATHS_HPP

include/fggl/scenes/game.hpp

@@ -20,33 +20,68 @@
 #define FGGL_SCENES_GAME_HPP
 
 #include "fggl/app.hpp"
+#include "fggl/entity/entity.hpp"
 #include "fggl/phys/types.hpp"
 
 namespace fggl::scenes {
 
+	class GameBase : public fggl::AppState {
+
+		public:
+			explicit GameBase(fggl::App &app);
+
+			void update(float dt) override;
+			void render(fggl::gfx::Graphics &gfx) override = 0;
+
+		protected:
+			inline auto input() -> input::Input & {
+				return *m_input;
+			}
+
+			inline void returnToMenu() {
+				m_owner.change_state(m_previous);
+			}
+
+		private:
+			input::Input *m_input;
+			std::string m_previous = "menu";
+	};
+
 	class Game : public fggl::AppState {
 
 		public:
-			explicit Game(fggl::App& app);
+			explicit Game(fggl::App &app);
 
 			void activate() override;
 			void deactivate() override;
 
-			void update() override;
-			void render(fggl::gfx::Graphics& gfx) override;
+			void update(float dt) override;
+			void render(fggl::gfx::Graphics &gfx) override;
 
-		protected:
-			inline auto world() -> ecs3::World& {
+			inline auto world() -> entity::EntityManager & {
 				return *m_world;
 			}
 
-			inline auto input() -> input::Input& {
+
+		protected:
+			bool hasPhys() const {
+				return m_phys != nullptr;
+			}
+
+			inline auto phys() -> phys::PhysicsEngine & {
+				assert(m_phys != nullptr);
+				return *m_phys;
+			}
+
+			inline auto input() -> input::Input & {
 				return *m_input;
 			}
 
+			bool m_debug;
+
 		private:
-			std::shared_ptr<input::Input> m_input;
-			std::unique_ptr<ecs3::World> m_world;
+			input::Input *m_input;
+			std::unique_ptr<entity::EntityManager> m_world;
 			std::unique_ptr<phys::PhysicsEngine> m_phys;
 			std::string m_previous = "menu";
 	};

include/fggl/scenes/menu.hpp

@@ -26,29 +26,29 @@
 
 namespace fggl::scenes {
 
-	using callback = std::function<void(void)>;
+	using Callback = std::function<void(void)>;
 
 	class BasicMenu : public AppState {
 		public:
 			explicit BasicMenu(App &owner);
 
-			void update() override;
+			void update(float dt) override;
 			void render(gfx::Graphics &paint) override;
 
 			void activate() override;
 			void deactivate() override;
 
-			void add(const std::string &label, callback cb);
+			void add(const std::string &label, const Callback& /*cb*/);
 
 		private:
-			std::shared_ptr<input::Input> m_inputs;
-			std::map<const std::string, callback> m_items;
+			input::Input *m_inputs;
+			std::map<const std::string, Callback> m_items;
 
 			// menu state
 			std::string m_active;
 			math::vec2 m_cursorPos;
 			gui::Container m_canvas;
-			gui::Widget* m_hover;
+			gui::Widget *m_hover;
 	};
 
 } // namepace fggl::scenes

include/fggl/script/engine.hpp

+/*
+ * This file is part of FGGL.
+ *
+ * FGGL is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any
+ * later version.
+ *
+ * FGGL is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License along with FGGL.
+ * If not, see <https://www.gnu.org/licenses/>.
+ */
+
+//
+// Created by webpigeon on 15/10/22.
+//
+
+#ifndef FGGL_SCRIPT_ENGINE_H
+#define FGGL_SCRIPT_ENGINE_H
+
+#include "fggl/modules/module.hpp"
+
+namespace fggl::script {
+
+	class ScriptEngine {
+		public:
+			virtual ~ScriptEngine() = default;
+
+			// TODO use protected virtual pattern
+
+			// scene callbacks
+			virtual void onActivate() = 0;
+			virtual void onDeactivate() = 0;
+			virtual void onUpdate() = 0;
+
+			// trigger callback
+			virtual void onEvent(const std::string& name) = 0;
+
+			// run code in engine
+			virtual bool run(const char* script) = 0;
+			virtual bool load(const char* filename) = 0;
+
+			virtual void setGlobal(const char* name, void* ptr) = 0;
+	};
+
+	class ScriptProvider {
+		public:
+			constexpr static const modules::ServiceName service = modules::make_service("fggl::script::service");
+			virtual ScriptEngine* create() = 0;
+	};
+
+}
+
+#endif //FGGL_SCRIPT_ENGINE_H

include/fggl/util/guid.hpp

+/*
+ * This file is part of FGGL.
+ *
+ * FGGL is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any
+ * later version.
+ *
+ * FGGL is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License along with FGGL.
+ * If not, see <https://www.gnu.org/licenses/>.
+ */
+
+//
+// Created by webpigeon on 23/07/22.
+// See http://www.isthe.com/chongo/tech/comp/fnv/
+//
+
+#ifndef FGGL_UTIL_GUID_HPP
+#define FGGL_UTIL_GUID_HPP
+
+#include <cstdint>
+#include <cassert>
+
+#include "fggl/util/safety.hpp"
+#include "fggl/debug/logging.hpp"
+
+namespace fggl::util {
+
+	using GUID = OpaqueName<std::uint64_t, struct GuidTag>;
+
+	constexpr uint32_t FNV_PRIME_32 = 0x01000193;
+	constexpr uint32_t FNV_OFFSET_BASIS_32 = 0x811c9dc5;
+	constexpr uint64_t FNV_PRIME_64 = 0x00000100000001B3;
+	constexpr uint64_t FNV_OFFSET_BASIS_64 = 0xcbf29ce484222325;
+
+	/**
+	 * Folwer-Noll-Vo 32-bit hash function.
+	 *
+	 * @param str the string to hash.
+	 * @return the hashed value
+	 */
+	constexpr uint32_t hash_fnv1a_32(const char *str) {
+		assert(str != nullptr);
+		uint32_t hash = FNV_OFFSET_BASIS_32;
+		for (int i = 0; str[i] != '\0'; i++) {
+			hash = hash ^ str[i];
+			hash = hash * FNV_PRIME_32;
+		}
+		return hash;
+	}
+
+	/**
+	 * Folwer-Noll-Vo 64-bit hash function.
+	 *
+	 * @param str the string to be hashed
+	 * @return the hashed value
+	 */
+	constexpr uint64_t hash_fnv1a_64(const char *str) {
+		assert(str != nullptr);
+		uint64_t hash = FNV_OFFSET_BASIS_64;
+		for (int i = 0; str[i] != '\0'; i++) {
+			hash = hash ^ str[i];
+			hash = hash * FNV_PRIME_64;
+		}
+		return hash;
+	}
+
+	template<unsigned N>
+	struct FString {
+		char c[N];
+	};
+
+	// https://stackoverflow.com/a/65440575
+	template<unsigned ...Len>
+	constexpr auto cat(const char (&...strings)[Len]) {
+		constexpr unsigned N = (... + Len) - sizeof...(Len);
+		FString<N + 1> result = {};
+		result.c[N] = '\0';
+
+		char* dst = result.c;
+		for (const char* src : {strings...}) {
+			for (; *src != '\0'; src++, dst++) {
+				*dst = *src;
+			}
+		}
+		return result;
+	}
+
+	// debug-only functions
+	#ifndef NDEBUG
+	GUID intern_string(const char *str);
+	std::string guid_to_string(GUID guid);
+	#endif
+
+	constexpr GUID make_guid(const char *str) {
+		return GUID(hash_fnv1a_64(str));
+	}
+
+	inline GUID make_guid_rt(const char* str) {
+		#ifndef NDEBUG
+		return intern_string(str);
+		#else
+		return make_guid(str);
+		#endif
+	}
+
+	inline GUID make_guid_rt(const std::string &str) {
+		return make_guid_rt(str.c_str());
+	}
+
+} // namespace fggl::util
+
+// formatter
+template<> struct fmt::formatter<fggl::util::GUID> {
+	constexpr auto parse(format_parse_context& ctx) -> decltype(ctx.begin()) {
+		return ctx.begin();
+	}
+
+	template <typename FormatContext>
+	auto format(const fggl::util::GUID& guid, FormatContext& ctx) const -> decltype(ctx.out()) {
+		#ifndef NDEBUG
+		return fmt::format_to(ctx.out(), "GUID[{}]", guid_to_string(guid));
+		#else
+		return fmt::format_to(ctx.out(), "GUID[{}]", guid.get());
+		#endif
+	}
+};
+
+
+fggl::util::GUID operator "" _fid(const char *str);
+fggl::util::GUID operator "" _fid(const char *str, std::size_t);
+
+#endif //FGGL_UTIL_GUID_HPP

include/fggl/util/safety.hpp

+/*
+ * This file is part of FGGL.
+ *
+ * FGGL is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any
+ * later version.
+ *
+ * FGGL is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License along with FGGL.
+ * If not, see <https://www.gnu.org/licenses/>.
+ */
+
+//
+// Created by webpigeon on 27/06/22.
+//
+
+#ifndef FGGL_UTIL_SAFETY_HPP
+#define FGGL_UTIL_SAFETY_HPP
+
+#include <string>
+
+namespace fggl::util {
+
+	/**
+	 * A type-safe opaque handle.
+	 *
+	 * Lots of low-level libraries we use pass around handles as some primative type. It's fairly easy to accidentally
+	 * mix these up. This wrapper's job is to make sure that mixing up handle types is impossible (and results in
+	 * compiler errors).
+	 *
+	 * @tparam T the underling type of the handle.
+	 * @tparam Tag a unique tag used to identify the handle type.
+	 */
+	template<typename T, typename Tag>
+	struct OpaqueName {
+		private:
+			T m_value;
+
+		public:
+			explicit constexpr OpaqueName(T value) : m_value(value) {}
+
+			constexpr OpaqueName() : m_value() {}
+
+			constexpr T get() const {
+				return m_value;
+			}
+
+			/**
+			 * Check for equality of two handles.
+			 *
+			 * Two values are considered the same of the values contained inside them are considered equal, and both
+			 * types share the same tagging interface.
+			 *
+			 * @param other the value being compared against.
+			 * @return true iff the contained values are equal
+			 */
+			bool operator==(const OpaqueName<T, Tag> &other) const {
+				return m_value == other.m_value;
+			}
+
+			/**
+			 * Check for equality of two handles.
+			 *
+			 * Two values are considered the same of the values contained inside them are considered equal, and both
+			 * types share the same tagging interface.
+			 *
+			 * @param other the value being compared against.
+			 * @return true iff the contained values are not equal
+			 */
+			bool operator!=(const OpaqueName<T, Tag> &other) const {
+				return m_value != other.m_value;
+			}
+
+			bool operator<(const OpaqueName<T, Tag> &other) const {
+				return m_value < other.m_value;
+			}
+
+			std::strong_ordering operator<=>(const OpaqueName<T, Tag> &other) const noexcept {
+				return m_value <=> other.m_value;
+			}
+
+			/**
+			 * Generate a new tagged instance of a handle.
+			 */
+			constexpr static OpaqueName<T, Tag> make(T value) {
+				return OpaqueName<T, Tag>(value);
+			}
+	};
+
+} // namespace fggl::util
+
+#endif //FGGL_UTIL_SAFETY_HPP