crown-engine/engine/resource/physics_resource.cpp

/*
 * Copyright (c) 2012-2014 Daniele Bartolini and individual contributors.
 * License: https://github.com/taylor001/crown/blob/master/LICENSE
 */

#include "physics_resource.h"
#include "physics_types.h"
#include "filesystem.h"
#include "json_parser.h"
#include "string_utils.h"
#include "dynamic_string.h"
#include "map.h"
#include "quaternion.h"
#include "compile_options.h"
#include <algorithm>

namespace crown
{
namespace physics_resource
{
	struct Shape
	{
		const char* name;
		ShapeType::Enum type;
	};

	static const Shape s_shape[ShapeType::COUNT] =
	{
		{ "sphere",  ShapeType::SPHERE  },
		{ "capsule", ShapeType::CAPSULE },
		{ "box",     ShapeType::BOX     },
		{ "plane",   ShapeType::PLANE   }
	};

	struct Joint
	{
		const char* name;
		JointType::Enum type;
	};

	static const Joint s_joint[JointType::COUNT] =
	{
		{ "fixed",     JointType::FIXED     },
		{ "spherical", JointType::SPHERICAL },
		{ "revolute",  JointType::REVOLUTE  },
		{ "prismatic", JointType::PRISMATIC },
		{ "distance",  JointType::DISTANCE  },
		{ "d6",        JointType::D6        }
	};

	static uint32_t shape_type_to_enum(const char* type)
	{
		for (uint32_t i = 0; i < ShapeType::COUNT; i++)
		{
			if (strcmp(type, s_shape[i].name) == 0)
				return s_shape[i].type;
		}

		CE_FATAL("Bad shape type");
		return 0;
	}

	static uint32_t joint_type_to_enum(const char* type)
	{
		for (uint32_t i = 0; i < JointType::COUNT; i++)
		{
			if (strcmp(type, s_joint[i].name) == 0)
				return s_joint[i].type;
		}

		CE_FATAL("Bad joint type");
		return 0;
	}

	void parse_controller(JSONElement e, ControllerResource& controller)
	{
		controller.name =             e.key("name").to_string_id();
		controller.height =           e.key("height").to_float();
		controller.radius =           e.key("radius").to_float();
		controller.slope_limit =      e.key("slope_limit").to_float();
		controller.step_offset =      e.key("step_offset").to_float();
		controller.contact_offset =   e.key("contact_offset").to_float();
		controller.collision_filter = e.key("collision_filter").to_string_id();
	}

	void parse_shapes(JSONElement e, Array<ShapeResource>& shapes)
	{
		Vector<DynamicString> keys(default_allocator());
		e.to_keys(keys);

		for (uint32_t k = 0; k < vector::size(keys); k++)
		{
			JSONElement shape 		= e.key(keys[k].c_str());

			ShapeResource sr;
			sr.name =        keys[k].to_string_id();
			sr.shape_class = shape.key("class").to_string_id();
			sr.material =    shape.key("material").to_string_id();
			sr.position =    shape.key("position").to_vector3();
			sr.rotation =    shape.key("rotation").to_quaternion();

			DynamicString stype; shape.key("type").to_string(stype);
			sr.type = shape_type_to_enum(stype.c_str());

			switch (sr.type)
			{
				case ShapeType::SPHERE:
				{
					sr.data_0 = shape.key("radius").to_float();
					break;
				}
				case ShapeType::CAPSULE:
				{
					sr.data_0 = shape.key("radius").to_float();
					sr.data_1 = shape.key("half_height").to_float();
					break;
				}
				case ShapeType::BOX:
				{
					sr.data_0 = shape.key("half_x").to_float();
					sr.data_1 = shape.key("half_y").to_float();
					sr.data_2 = shape.key("half_z").to_float();
					break;
				}
				case ShapeType::PLANE:
				{
					sr.data_0 = shape.key("n_x").to_float();
					sr.data_1 = shape.key("n_y").to_float();
					sr.data_2 = shape.key("n_z").to_float();
					sr.data_3 = shape.key("distance").to_float();
					break;
				}
				case ShapeType::CONVEX_MESH:
				{
					sr.resource = shape.key("mesh").to_resource_id("mesh");
					break;
				}
			}
			array::push_back(shapes, sr);
		}
	}

	void parse_actors(JSONElement e, Array<ActorResource>& actors, Array<ShapeResource>& actor_shapes, Array<uint32_t>& shape_indices)
	{
		Vector<DynamicString> keys(default_allocator());
		e.to_keys(keys);

		for (uint32_t k = 0; k < vector::size(keys); k++)
		{
			JSONElement actor 	= e.key(keys[k].c_str());

			ActorResource pa;
			pa.name =        keys[k].to_string_id();
			pa.node =        actor.key("node").to_string_id();
			pa.actor_class = actor.key("class").to_string_id();
			pa.mass =        actor.key("mass").to_float();
			pa.num_shapes =  actor.key("shapes").size();

			array::push_back(actors, pa);
			array::push_back(shape_indices, array::size(shape_indices));

			parse_shapes(actor.key("shapes"), actor_shapes);
		}
	}

	void parse_joints(JSONElement e, Array<JointResource>& joints)
	{
		Vector<DynamicString> keys(default_allocator());
		e.to_keys(keys);

		for (uint32_t k = 0; k < vector::size(keys); k++)
		{
			JSONElement joint			= e.key(keys[k].c_str());
			JSONElement type 			= joint.key("type");

			JointResource pj;
			pj.name = keys[k].to_string_id();
			DynamicString jtype; type.to_string(jtype);
			pj.type         = joint_type_to_enum(jtype.c_str());
			pj.actor_0      = joint.key("actor_0").to_string_id();
			pj.actor_1      = joint.key("actor_1").to_string_id();
			pj.anchor_0     = joint.key("anchor_0").to_vector3();
			pj.anchor_1     = joint.key("anchor_1").to_vector3();
			pj.restitution  = joint.key_or_nil("restitution").to_float(0.5f);
			pj.spring       = joint.key_or_nil("spring").to_float(100.0f);
			pj.damping      = joint.key_or_nil("damping").to_float(0.0f);
			pj.distance     = joint.key_or_nil("distance").to_float(1.0f);
			pj.breakable    = joint.key_or_nil("breakable").to_bool(false);
			pj.break_force  = joint.key_or_nil("break_force").to_float(3000.0f);
			pj.break_torque = joint.key_or_nil("break_torque").to_float(1000.0f);

			switch (pj.type)
			{
				case JointType::FIXED:
				{
					return;
				}
				case JointType::SPHERICAL:
				{
					pj.y_limit_angle = joint.key_or_nil("y_limit_angle").to_float(HALF_PI);
					pj.z_limit_angle = joint.key_or_nil("z_limit_angle").to_float(HALF_PI);
					pj.contact_dist =  joint.key_or_nil("contact_dist").to_float(0.0f);
					break;
				}
				case JointType::REVOLUTE:
				case JointType::PRISMATIC:
				{
					pj.lower_limit =  joint.key_or_nil("lower_limit").to_float(0.0f);
					pj.upper_limit =  joint.key_or_nil("upper_limit").to_float(0.0f);
					pj.contact_dist = joint.key_or_nil("contact_dist").to_float(0.0f);
					break;
				}
				case JointType::DISTANCE:
				{
					pj.max_distance = joint.key_or_nil("max_distance").to_float(0.0f);
					break;
				}
				case JointType::D6:
				{
					CE_FATAL("Not implemented");
					break;
				}
			}

			array::push_back(joints, pj);
		}
	}

	void compile(const char* path, CompileOptions& opts)
	{
		static const uint32_t VERSION = 1;

		Buffer buf = opts.read(path);
		JSONParser json(array::begin(buf));
		JSONElement root = json.root();

		bool m_has_controller = false;
		ControllerResource m_controller;

		// Read controller
		JSONElement controller = root.key_or_nil("controller");
		if (controller.is_nil())
		{
			m_has_controller = false;
		}
		else
		{
			parse_controller(controller, m_controller);
			m_has_controller = true;
		}

		Array<ActorResource> m_actors(default_allocator());
		Array<uint32_t> m_shapes_indices(default_allocator());
		Array<ShapeResource> m_shapes(default_allocator());
		Array<JointResource> m_joints(default_allocator());

		if (root.has_key("actors")) parse_actors(root.key("actors"), m_actors, m_shapes, m_shapes_indices);
		if (root.has_key("joints")) parse_joints(root.key("joints"), m_joints);

		PhysicsResource pr;
		pr.version = VERSION;
		pr.num_controllers = m_has_controller ? 1 : 0;
		pr.num_actors = array::size(m_actors);
		pr.num_joints = array::size(m_joints);

		uint32_t offt = sizeof(PhysicsResource);
		pr.controller_offset = offt; offt += sizeof(ControllerResource) * pr.num_controllers;
		pr.actors_offset = offt; offt += sizeof(ActorResource) * pr.num_actors;
		pr.joints_offset = offt;

		// Write all
		opts.write(pr.version);
		opts.write(pr.num_controllers);
		opts.write(pr.controller_offset);
		opts.write(pr.num_actors);
		opts.write(pr.actors_offset);
		opts.write(pr.num_joints);
		opts.write(pr.joints_offset);

		if (m_has_controller)
		{
			opts.write(m_controller.name);
			opts.write(m_controller.height);
			opts.write(m_controller.radius);
			opts.write(m_controller.slope_limit);
			opts.write(m_controller.step_offset);
			opts.write(m_controller.contact_offset);
			opts.write(m_controller.collision_filter);
		}

		for (uint32_t i = 0; i < array::size(m_actors); i++)
		{
			opts.write(m_actors[i].name);
			opts.write(m_actors[i].node);
			opts.write(m_actors[i].actor_class);
			opts.write(m_actors[i].mass);
			opts.write(m_actors[i].num_shapes);

			for (uint32_t ss = 0; ss < m_actors[i].num_shapes; ++ss)
			{
				const uint32_t base = m_shapes_indices[i];

				opts.write(m_shapes[base + ss].name);
				opts.write(m_shapes[base + ss].shape_class);
				opts.write(m_shapes[base + ss].type);
				opts.write(m_shapes[base + ss].material);
				opts.write(m_shapes[base + ss].resource);
				opts.write(m_shapes[base + ss].position);
				opts.write(m_shapes[base + ss].rotation);
				opts.write(m_shapes[base + ss].data_0);
				opts.write(m_shapes[base + ss].data_1);
				opts.write(m_shapes[base + ss].data_2);
				opts.write(m_shapes[base + ss].data_3);
			}
		}

		for (uint32_t i = 0; i < array::size(m_joints); i++)
		{
			opts.write(m_joints[i].name);
			opts.write(m_joints[i].type);
			opts.write(m_joints[i].actor_0);
			opts.write(m_joints[i].actor_1);
			opts.write(m_joints[i].anchor_0);
			opts.write(m_joints[i].anchor_1);
			opts.write(m_joints[i].breakable);
			opts.write(m_joints[i]._pad[0]);
			opts.write(m_joints[i]._pad[1]);
			opts.write(m_joints[i]._pad[2]);
			opts.write(m_joints[i].break_force);
			opts.write(m_joints[i].break_torque);
			opts.write(m_joints[i].lower_limit);
			opts.write(m_joints[i].upper_limit);
			opts.write(m_joints[i].y_limit_angle);
			opts.write(m_joints[i].z_limit_angle);
			opts.write(m_joints[i].max_distance);
			opts.write(m_joints[i].contact_dist);
			opts.write(m_joints[i].restitution);
			opts.write(m_joints[i].spring);
			opts.write(m_joints[i].damping);
			opts.write(m_joints[i].distance);
		}
	}

	void* load(File& file, Allocator& a)
	{
		const size_t file_size = file.size();
		void* res = a.allocate(file_size);
		file.read(res, file_size);
		return res;
	}

	void online(StringId64 /*id*/, ResourceManager& /*rm*/)
	{
	}

	void offline(StringId64 /*id*/, ResourceManager& /*rm*/)
	{
	}

	void unload(Allocator& allocator, void* resource)
	{
		allocator.deallocate(resource);
	}

	bool has_controller(const PhysicsResource* pr)
	{
		return pr->num_controllers == 1;
	}

	const ControllerResource* controller(const PhysicsResource* pr)
	{
		CE_ASSERT(has_controller(pr), "Controller does not exist");
		ControllerResource* controller = (ControllerResource*) ((char*)pr + pr->controller_offset);
		return controller;
	}

	uint32_t num_actors(const PhysicsResource* pr)
	{
		return pr->num_actors;
	}

	const ActorResource* actor(const PhysicsResource* pr, uint32_t i)
	{
		CE_ASSERT(i < num_actors(pr), "Index out of bounds");
		ActorResource* actor = (ActorResource*) ((char*)pr + pr->actors_offset);
		return &actor[i];
	}

	uint32_t num_joints(const PhysicsResource* pr)
	{
		return pr->num_joints;
	}

	const JointResource* joint(const PhysicsResource* pr, uint32_t i)
	{
		CE_ASSERT(i < num_joints(pr), "Index out of bounds");
		JointResource* joint = (JointResource*) ((char*)pr + pr->joints_offset);
		return &joint[i];
	}
} // namespace physics_resource

namespace actor_resource
{
	uint32_t num_shapes(const ActorResource* ar)
	{
		return ar->num_shapes;
	}

	const ShapeResource* shape(const ActorResource* ar, uint32_t i)
	{
		CE_ASSERT(i < num_shapes(ar), "Index out of bounds");
		ShapeResource* shape = (ShapeResource*) (ar + 1);
		return &shape[i];
	}
} // namespace actor_resource

namespace physics_config_resource
{
	static Map<DynamicString, uint32_t>* s_ftm = NULL;

	struct ObjectName
	{
		StringId32 name;
		uint32_t index;

		bool operator()(const ObjectName& a, const ObjectName& b)
		{
			return a.name < b.name;
		}
	};

	void parse_materials(JSONElement e, Array<ObjectName>& names, Array<PhysicsMaterial>& objects)
	{
		Vector<DynamicString> keys(default_allocator());
		e.to_keys(keys);

		for (uint32_t i = 0; i < vector::size(keys); i++)
		{
			JSONElement material = e.key(keys[i].c_str());

			// Read material name
			ObjectName mat_name;
			mat_name.name = keys[i].to_string_id();
			mat_name.index = i;

			// Read material object
			PhysicsMaterial mat;
			mat.static_friction =  material.key("static_friction").to_float();
			mat.dynamic_friction = material.key("dynamic_friction").to_float();
			mat.restitution =      material.key("restitution").to_float();

			array::push_back(names, mat_name);
			array::push_back(objects, mat);
		}
	}

	void parse_shapes(JSONElement e, Array<ObjectName>& names, Array<PhysicsShape2>& objects)
	{
		Vector<DynamicString> keys(default_allocator());
		e.to_keys(keys);

		for (uint32_t i = 0; i < vector::size(keys); i++)
		{
			JSONElement shape = e.key(keys[i].c_str());

			// Read shape name
			ObjectName shape_name;
			shape_name.name = keys[i].to_string_id();
			shape_name.index = i;

			// Read shape object
			PhysicsShape2 ps2;
			ps2.trigger =          shape.key("trigger").to_bool();
			ps2.collision_filter = shape.key("collision_filter").to_string_id();

			array::push_back(names, shape_name);
			array::push_back(objects, ps2);
		}
	}

	void parse_actors(JSONElement e, Array<ObjectName>& names, Array<PhysicsActor2>& objects)
	{
		Vector<DynamicString> keys(default_allocator());
		e.to_keys(keys);

		for (uint32_t i = 0; i < vector::size(keys); i++)
		{
			JSONElement actor			= e.key(keys[i].c_str());

			// Read actor name
			ObjectName actor_name;
			actor_name.name = keys[i].to_string_id();
			actor_name.index = i;

			// Read actor object
			PhysicsActor2 pa2;
			pa2.linear_damping =  actor.key_or_nil("linear_damping").to_float(0.0f);
			pa2.angular_damping = actor.key_or_nil("angular_damping").to_float(0.05f);

			JSONElement dynamic			= actor.key_or_nil("dynamic");
			JSONElement kinematic		= actor.key_or_nil("kinematic");
			JSONElement disable_gravity	= actor.key_or_nil("disable_gravity");

			pa2.flags = 0;
			if (!dynamic.is_nil())
			{
				pa2.flags |= dynamic.to_bool() ? 1 : 0;
			}
			if (!kinematic.is_nil())
			{
				pa2.flags |= kinematic.to_bool() ? PhysicsActor2::KINEMATIC : 0;
			}
			if (!disable_gravity.is_nil())
			{
				pa2.flags |= disable_gravity.to_bool() ? PhysicsActor2::DISABLE_GRAVITY : 0;
			}

			array::push_back(names, actor_name);
			array::push_back(objects, pa2);
		}
	}

	uint32_t new_filter_mask()
	{
		static uint32_t mask = 1;
		CE_ASSERT(mask != 0x80000000u, "Too many collision filters");
		uint32_t tmp = mask;
		mask = mask << 1;
		return tmp;
	}

	uint32_t filter_to_mask(const char* f)
	{
		if (map::has(*s_ftm, DynamicString(f)))
			return map::get(*s_ftm, DynamicString(f), 0u);

		uint32_t new_filter = new_filter_mask();
		map::set(*s_ftm, DynamicString(f), new_filter);
		return new_filter;
	}

	uint32_t collides_with_to_mask(const Vector<DynamicString>& coll_with)
	{
		uint32_t mask = 0;

		for (uint32_t i = 0; i < vector::size(coll_with); i++)
		{
			mask |= filter_to_mask(coll_with[i].c_str());
		}

		return mask;
	}

	void parse_collision_filters(JSONElement e, Array<ObjectName>& names, Array<PhysicsCollisionFilter>& objects)
	{
		Vector<DynamicString> keys(default_allocator());
		e.to_keys(keys);

		for (uint32_t i = 0; i < vector::size(keys); i++)
		{
			JSONElement filter			= e.key(keys[i].c_str());
			JSONElement collides_with	= filter.key("collides_with");

			// Read filter name
			ObjectName filter_name;
			filter_name.name = keys[i].to_string_id();
			filter_name.index = i;

			// Build mask
			Vector<DynamicString> collides_with_vector(default_allocator());
			collides_with.to_array(collides_with_vector);

			PhysicsCollisionFilter pcf;
			pcf.me = filter_to_mask(keys[i].c_str());
			pcf.mask = collides_with_to_mask(collides_with_vector);

			// printf("FILTER: %s (me = %X, mask = %X\n", keys[i].c_str(), pcf.me, pcf.mask);

			array::push_back(names, filter_name);
			array::push_back(objects, pcf);
		}
	}

	void compile(const char* path, CompileOptions& opts)
	{
		static const uint32_t VERSION = 1;

		Buffer buf = opts.read(path);
		JSONParser json(array::begin(buf));
		JSONElement root = json.root();

		typedef Map<DynamicString, uint32_t> FilterMap;
		s_ftm = CE_NEW(default_allocator(), FilterMap)(default_allocator());

		Array<ObjectName> material_names(default_allocator());
		Array<PhysicsMaterial> material_objects(default_allocator());
		Array<ObjectName> shape_names(default_allocator());
		Array<PhysicsShape2> shape_objects(default_allocator());
		Array<ObjectName> actor_names(default_allocator());
		Array<PhysicsActor2> actor_objects(default_allocator());
		Array<ObjectName> filter_names(default_allocator());
		Array<PhysicsCollisionFilter> filter_objects(default_allocator());

		// Parse materials
		if (root.has_key("collision_filters")) parse_collision_filters(root.key("collision_filters"), filter_names, filter_objects);
		if (root.has_key("materials")) parse_materials(root.key("materials"), material_names, material_objects);
		if (root.has_key("shapes")) parse_shapes(root.key("shapes"), shape_names, shape_objects);
		if (root.has_key("actors")) parse_actors(root.key("actors"), actor_names, actor_objects);

		// Sort objects by name
		std::sort(array::begin(material_names), array::end(material_names), ObjectName());
		std::sort(array::begin(shape_names), array::end(shape_names), ObjectName());
		std::sort(array::begin(actor_names), array::end(actor_names), ObjectName());
		std::sort(array::begin(filter_names), array::end(filter_names), ObjectName());

		// Setup struct for writing
		PhysicsConfigResource pcr;
		pcr.version = VERSION;
		pcr.num_materials = array::size(material_names);
		pcr.num_shapes = array::size(shape_names);
		pcr.num_actors = array::size(actor_names);
		pcr.num_filters = array::size(filter_names);

		uint32_t offt = sizeof(PhysicsConfigResource);
		pcr.materials_offset = offt;
		offt += sizeof(StringId32) * pcr.num_materials;
		offt += sizeof(PhysicsMaterial) * pcr.num_materials;

		pcr.shapes_offset = offt;
		offt += sizeof(StringId32) * pcr.num_shapes;
		offt += sizeof(PhysicsShape2) * pcr.num_shapes;

		pcr.actors_offset = offt;
		offt += sizeof(StringId32) * pcr.num_actors;
		offt += sizeof(PhysicsActor2) * pcr.num_actors;

		pcr.filters_offset = offt;
		offt += sizeof(StringId32) * pcr.num_filters;
		offt += sizeof(PhysicsCollisionFilter) * pcr.num_filters;

		// Write all
		opts.write(pcr.version);
		opts.write(pcr.num_materials);
		opts.write(pcr.materials_offset);
		opts.write(pcr.num_shapes);
		opts.write(pcr.shapes_offset);
		opts.write(pcr.num_actors);
		opts.write(pcr.actors_offset);
		opts.write(pcr.num_filters);
		opts.write(pcr.filters_offset);

		// Write material names
		for (uint32_t i = 0; i < pcr.num_materials; i++)
		{
			opts.write(material_names[i].name);
		}

		// Write material objects
		for (uint32_t i = 0; i < pcr.num_materials; i++)
		{
			opts.write(material_objects[material_names[i].index].static_friction);
			opts.write(material_objects[material_names[i].index].dynamic_friction);
			opts.write(material_objects[material_names[i].index].restitution);
		}

		// Write shape names
		for (uint32_t i = 0; i < pcr.num_shapes; i++)
		{
			opts.write(shape_names[i].name);
		}

		// Write material objects
		for (uint32_t i = 0; i < pcr.num_shapes; i++)
		{
			opts.write(shape_objects[shape_names[i].index].collision_filter);
			opts.write(shape_objects[shape_names[i].index].trigger);
			opts.write(shape_objects[shape_names[i].index]._pad[0]);
			opts.write(shape_objects[shape_names[i].index]._pad[1]);
			opts.write(shape_objects[shape_names[i].index]._pad[2]);
		}

		// Write actor names
		for (uint32_t i = 0; i < pcr.num_actors; i++)
		{
			opts.write(actor_names[i].name);
		}

		// Write actor objects
		for (uint32_t i = 0; i < pcr.num_actors; i++)
		{
			opts.write(actor_objects[actor_names[i].index].linear_damping);
			opts.write(actor_objects[actor_names[i].index].angular_damping);
			opts.write(actor_objects[actor_names[i].index].flags);
		}

		// Write filter names
		for (uint32_t i = 0; i < pcr.num_filters; i++)
		{
			opts.write(filter_names[i].name);
		}

		// Write filter objects
		for (uint32_t i = 0; i < pcr.num_filters; i++)
		{
			opts.write(filter_objects[filter_names[i].index].me);
			opts.write(filter_objects[filter_names[i].index].mask);
		}

		CE_DELETE(default_allocator(), s_ftm);
	}

	void* load(File& file, Allocator& a)
	{
		const size_t file_size = file.size();
		void* res = a.allocate(file_size);
		file.read(res, file_size);
		return res;
	}

	void online(StringId64 /*id*/, ResourceManager& /*rm*/)
	{
	}

	void offline(StringId64 /*id*/, ResourceManager& /*rm*/)
	{
	}

	void unload(Allocator& allocator, void* resource)
	{
		allocator.deallocate(resource);
	}

	uint32_t num_materials(const PhysicsConfigResource* pcr)
	{
		return pcr->num_materials;
	}

	/// Returns the material with the given @a name
	const PhysicsMaterial* material(const PhysicsConfigResource* pcr, StringId32 name)
	{
		StringId32* begin = (StringId32*) ((char*)pcr + pcr->materials_offset);
		StringId32* end = begin + num_materials(pcr);
		StringId32* id = std::find(begin, end, name);
		CE_ASSERT(id != end, "Material not found");
		return material_by_index(pcr, id - begin);
	}

	const PhysicsMaterial* material_by_index(const PhysicsConfigResource* pcr, uint32_t i)
	{
		CE_ASSERT(i < num_materials(pcr), "Index out of bounds");
		const PhysicsMaterial* base = (PhysicsMaterial*) ((char*)pcr + pcr->materials_offset + sizeof(StringId32) * num_materials(pcr));
		return &base[i];
	}

	uint32_t num_shapes(const PhysicsConfigResource* pcr)
	{
		return pcr->num_shapes;
	}

	const PhysicsShape2* shape(const PhysicsConfigResource* pcr, StringId32 name)
	{
		StringId32* begin = (StringId32*) ((char*)pcr + pcr->shapes_offset);
		StringId32* end = begin + num_shapes(pcr);
		StringId32* id = std::find(begin, end, name);
		CE_ASSERT(id != end, "Shape not found");
		return shape_by_index(pcr, id - begin);
	}

	const PhysicsShape2* shape_by_index(const PhysicsConfigResource* pcr, uint32_t i)
	{
		CE_ASSERT(i < num_shapes(pcr), "Index out of bounds");
		const PhysicsShape2* base = (PhysicsShape2*) ((char*)pcr + pcr->shapes_offset + sizeof(StringId32) * num_shapes(pcr));
		return &base[i];
	}

	uint32_t num_actors(const PhysicsConfigResource* pcr)
	{
		return pcr->num_actors;
	}

	/// Returns the actor with the given @a name
	const PhysicsActor2* actor(const PhysicsConfigResource* pcr, StringId32 name)
	{
		StringId32* begin = (StringId32*) ((char*)pcr + pcr->actors_offset);
		StringId32* end = begin + num_actors(pcr);
		StringId32* id = std::find(begin, end, name);
		CE_ASSERT(id != end, "Actor not found");
		return actor_by_index(pcr, id - begin);
	}

	const PhysicsActor2* actor_by_index(const PhysicsConfigResource* pcr, uint32_t i)
	{
		CE_ASSERT(i < num_actors(pcr), "Index out of bounds");
		const PhysicsActor2* base = (PhysicsActor2*) ((char*)pcr + pcr->actors_offset + sizeof(StringId32) * num_actors(pcr));
		return &base[i];
	}

	uint32_t num_filters(const PhysicsConfigResource* pcr)
	{
		return pcr->num_filters;
	}

	const PhysicsCollisionFilter* filter(const PhysicsConfigResource* pcr, StringId32 name)
	{
		StringId32* begin = (StringId32*) ((char*)pcr + pcr->filters_offset);
		StringId32* end = begin + num_filters(pcr);
		StringId32* id = std::find(begin, end, name);
		CE_ASSERT(id != end, "Filter not found");
		return filter_by_index(pcr, id - begin);
	}

	const PhysicsCollisionFilter* filter_by_index(const PhysicsConfigResource* pcr, uint32_t i)
	{
		CE_ASSERT(i < num_filters(pcr), "Index out of bounds");
		const PhysicsCollisionFilter* base = (PhysicsCollisionFilter*) ((char*)pcr + pcr->filters_offset + sizeof(StringId32) * num_filters(pcr));
		return &base[i];
	}
} // namespace physics_config_resource
} // namespace crown