[camera] Refactor camera code

[IAmNotHanni]

Blocked by #518

Overview

• Do not reset camera position when window is resized
• Change return type of camera methods to const reference so method calls can be chained
• Chain method calls to camera wrapper methods
• Make camera code thread-safe
• Improve code documentation

[IceflowRE]

Suggested change

	/// @note We will implement more camera types in the future
	/// @param type The camera type
	/// @param type The camera type
	/// @note We will implement more camera types in the future

Param before notes.

[IceflowRE]

Iam not a friend of using an enum for indicating a camera movement. I would allow direct manipulations via vectors.
In general i don't really like the current state of this camera class.
This camera class is already highly specified and implemented and thus limited in adding new camera types.
By handling inputs and the resulting camera movement.

I would suggest to make a more general camera class with the most important methods like direction, position, plane, etc.
Then inherit from this base camera and implement a PlayerCamera which has more traits like rotation speed, movement speed etc.

In my eyes is camera movement already part of the game (user) code and not the engine code. We should only provide callbacks or signals to inputs.

[yeetari]

Nice work, though I'm not a huge fan of using ThisType &foo() { return *this; } everywhere (imo it's main use case is for builders). Also I agree with Iceflower that the camera code would be nicer if it ws inheritance based, something like:

struct Camera {
    virtual void update();
    
    virtual glm::vec3f forward() const;
    virtual glm::mat4f view_matrix() const;
};

class FreeCamera  : public Camera {};

[westernheld]

If you resize the window just in one direction or with a different ratio in width and height you will cause the camera make squares out of the cubes. See Screenshot.

[IAmNotHanni]

This has lower priority atm. I will work on other pull requests for now :)

[IAmNotHanni]

After some thinking, I came to the conclusion that it's not worth it to continue with this pull request. The reasons are the following:

• I want to abstract the camera as an entiy in EnTT anyways, so the entire code will be changed later
• The changes introduced in this pull request are minimal, and I would do many things differently now. For example, I would not have a builder pattern for setting the camera variables anymore, as this should be reserved for other code parts.
• Thread safety can be implemented based on the entity component system.
• The bug Resizing window causes camera position to reset #411 will be fixed by [*] Refactor rendergraph #533

Thanks anyways for the review guys, I will take notes on how to do it like this for future pull requests.