Variadic and template specializations for serialize and deserialize

[Sebanisu]

Describe the issue (if no issue has been made)

Serialize and Deserialize were 2 large functions. I thought it might become hard to manage.

Proposed fix

This gives you a separate function for each component, for both serializing and deserializing. I grouped them by Component and placed them at the bottom of SceneSerializer.cpp. The default catch all case is deleted so if you add a new Component to AllComponents then you will get a compile time error. So you know what you forgot and can fix it.

Hazel/Hazel/src/Hazel/Scene/SceneSerializer.cpp

Lines 234 to 238 in 73d478e

	template<typename Component>
	static void SerializeEntityComponent(YAML::Emitter&, Entity) = delete;
	template<typename Component>
	void DeserializeEntryComponent(YAML::detail::iterator_value& entity, Entity&) = delete;

PR impact (Make sure to add closing keywords)

List of related issues/PRs this will solve:
I took a different approach than the previous ideas I had in #496. Instead of changing AllComponents, I altered my function to accept more template arguments. So this way we are serializing TagComponent.

Hazel/Hazel/src/Hazel/Scene/SceneSerializer.cpp

Lines 515 to 547 in 73d478e

	template<typename...Component>
	static void SerializeEntityComponents(YAML::Emitter& out, Entity entity)
	{
	(SerializeEntityComponent<Component>(out, entity), ...);
	}
	template<typename...Component>
	static void DeserializeEntryComponents(YAML::detail::iterator_value& entity, Entity& deserializedEntity)
	{
	(DeserializeEntryComponent<Component>(entity, deserializedEntity), ...);
	}
	template<typename... PrefixComponent, typename...Component>
	static void SerializeEntityComponents(ComponentGroup<Component...>, YAML::Emitter& out, Entity entity)
	{
	SerializeEntityComponents<PrefixComponent..., Component...>(out, entity);
	}
	template<typename... PrefixComponent, typename...Component>
	static void DeserializeEntryComponents(ComponentGroup<Component...>, YAML::detail::iterator_value& entity, Entity& deserializedEntity)
	{
	DeserializeEntryComponents<PrefixComponent..., Component...>(entity, deserializedEntity);
	}
	static void SerializeAllEntityComponents(YAML::Emitter& out, Entity entity)
	{
	SerializeEntityComponents<TagComponent>(AllComponents{}, out, entity);
	}
	static void DeserializeAllEntryComponents(YAML::detail::iterator_value& entity, Entity& deserializedEntity)
	{
	DeserializeEntryComponents(AllComponents{}, entity, deserializedEntity);
	}

TagComponent is deserialized on creation of an entity. So we only need it for serialization.

Hazel/Hazel/src/Hazel/Scene/SceneSerializer.cpp

Lines 208 to 213 in 73d478e

	uint64_t uuid = entity["Entity"].as<uint64_t>();
	std::string name;
	auto tagComponent = entity["TagComponent"];
	if (tagComponent)
	name = tagComponent["Tag"].as<std::string>();

Additional context

Add any other context about the solution here. Did you test the solution on all (relevant) platforms?
I tested on Windows 10, with a Nvidia 980 TI.

We don't serialize with NativeScriptComponent. I just put a TODO there maybe we can serialize it in the future.

Hazel/Hazel/src/Hazel/Scene/SceneSerializer.cpp

Lines 503 to 513 in 73d478e

	template<>
	static void SerializeEntityComponent<NativeScriptComponent>(YAML::Emitter& out, Entity entity)
	{
	//TODO: serialize NativeScriptComponent?
	}
	template<>
	static void DeserializeEntryComponent<NativeScriptComponent>(YAML::detail::iterator_value&, Entity&)
	{
	//TODO: deserialize NativeScriptComponent?
	}

CircleCollider2DComponent was missing from my original commit:

Hazel/Hazel/src/Hazel/Scene/SceneSerializer.cpp

Lines 466 to 501 in 73d478e

	template<>
	static void SerializeEntityComponent<CircleCollider2DComponent>(YAML::Emitter& out, Entity entity)
	{
	if (entity.HasComponent<CircleCollider2DComponent>())
	{
	out << YAML::Key << "CircleCollider2DComponent";
	out << YAML::BeginMap; // CircleCollider2DComponent
	auto& cc2dComponent = entity.GetComponent<CircleCollider2DComponent>();
	out << YAML::Key << "Offset" << YAML::Value << cc2dComponent.Offset;
	out << YAML::Key << "Radius" << YAML::Value << cc2dComponent.Radius;
	out << YAML::Key << "Density" << YAML::Value << cc2dComponent.Density;
	out << YAML::Key << "Friction" << YAML::Value << cc2dComponent.Friction;
	out << YAML::Key << "Restitution" << YAML::Value << cc2dComponent.Restitution;
	out << YAML::Key << "RestitutionThreshold" << YAML::Value << cc2dComponent.RestitutionThreshold;
	out << YAML::EndMap; // CircleCollider2DComponent
	}
	}
	template<>
	static void DeserializeEntryComponent<CircleCollider2DComponent>(YAML::detail::iterator_value& entity, Entity& deserializedEntity)
	{
	auto circleCollider2DComponent = entity["CircleCollider2DComponent"];
	if (circleCollider2DComponent)
	{
	auto& bc2d = deserializedEntity.AddComponent<CircleCollider2DComponent>();
	bc2d.Offset = circleCollider2DComponent["Offset"].as<glm::vec2>();
	bc2d.Radius = circleCollider2DComponent["Radius"].as<float>();
	bc2d.Density = circleCollider2DComponent["Density"].as<float>();
	bc2d.Friction = circleCollider2DComponent["Friction"].as<float>();
	bc2d.Restitution = circleCollider2DComponent["Restitution"].as<float>();
	bc2d.RestitutionThreshold = circleCollider2DComponent["RestitutionThreshold"].as<float>();
	}
	}

Cherno fixed this on his stream as well. So I just had to fix the merge conflicts.
Texture wasn't being serialized #561:
Added GetPath()

Hazel/Hazel/src/Hazel/Renderer/Texture.h

Line 17 in 73d478e

virtual const std::string & GetPath() const = 0;

Hazel/Hazel/src/Platform/OpenGL/OpenGLTexture.h

Line 19 in 73d478e

virtual const std::string& GetPath() const override { return m_Path; }

Serialize TexturePath:

Hazel/Hazel/src/Hazel/Scene/SceneSerializer.cpp

Lines 340 to 373 in 73d478e

	template<>
	static void SerializeEntityComponent<SpriteRendererComponent>(YAML::Emitter& out, Entity entity)
	{
	if (entity.HasComponent<SpriteRendererComponent>())
	{
	out << YAML::Key << "SpriteRendererComponent";
	out << YAML::BeginMap; // SpriteRendererComponent
	auto& spriteRendererComponent = entity.GetComponent<SpriteRendererComponent>();
	if (spriteRendererComponent.Texture && std::filesystem::exists(spriteRendererComponent.Texture->GetPath()))
	{
	out << YAML::Key << "TexturePath" << YAML::Value << spriteRendererComponent.Texture->GetPath();
	}
	out << YAML::Key << "Color" << YAML::Value << spriteRendererComponent.Color;
	out << YAML::Key << "TilingFactor" << YAML::Value << spriteRendererComponent.TilingFactor;
	out << YAML::EndMap; // SpriteRendererComponent
	}
	}
	template<>
	static void DeserializeEntryComponent<SpriteRendererComponent>(YAML::detail::iterator_value& entity, Entity& deserializedEntity)
	{
	auto spriteRendererComponent = entity["SpriteRendererComponent"];
	if (spriteRendererComponent)
	{
	auto& src = deserializedEntity.AddComponent<SpriteRendererComponent>();
	if(spriteRendererComponent["TexturePath"])
	src.Texture = Texture2D::Create(spriteRendererComponent["TexturePath"].as<std::string>());
	src.Color = spriteRendererComponent["Color"].as<glm::vec4>();
	if (spriteRendererComponent["TilingFactor"])
	src.TilingFactor = spriteRendererComponent["TilingFactor"].as<float>();
	}
	}

[Sebanisu]

One other way we could of done this is the move the serialize code into member functions of each component. Then we just call that. Though This seemed more in line with how you were already doing stuff.

[Sebanisu]

I just merged the upstream/master into my branch as it was several months old. I wanted to make sure stuff was still working. 6e309d4

I noticed CircleCollider2DComponent was missing from Deserialize and Serialize code. So I added that. c64ec68

Texture wasn't being saved. OpenGLTexture does store a path. So I added a virtual GetPath() function. So we had something to serialize. #561 c64ec68

[Sebanisu]

This pull request was originally on dev and now on it's master. Some of the changes in my pull request are from dev.
entt.hpp Entity.h are included but I haven't touched those files. TheCherno made those commits.

There was one commit I accidentally reverted. So I had a revert revert. 7b19ce5

[Sebanisu]

I cherry picked my commits and reset this branch so I no longer have anything from the dev branch in my pull request.

[Sebanisu]

Cherno added TexturePath and Tiling Factor.
Main thing I did differently is I checked to see if the path exists on saving.
I resolved the merge conflicts from the latest stream.
Back to compiling again. :)