Physics

[Vrekt]

BTW: I'm going to assign more people to this once they accept.

I'm wanting to add basic physics to the game. Something easy and simple to use. If you have an ideas please share them with me below.

Something like gravity would be simple enough. I'm thinking:

BasicPhysics.handleGravity(myEntity, direction, speed);
or something where the entity implements a physics class and it handles it automatically. I'm not sure still thinking about how to implement it.

[Vrekt]

Basic velocity class -- improve later, thanks minz
https://hastebin.com/edavijinif.java

[rickbau5]

Cool, I’ll take a look

[minz1]

2nd revision: https://hastebin.com/azilisasok.java

This doesn't take into account collisions, but gravity should be accounted for.

[rickbau5]

So I'm not sure that Velocity needs to be a separate class. Velocity is really just a property like position x and y and is only meaningful in that context so I think it makes sense to have it part of the Entity class. Entitys are going to be the only things that really use it as typically entities are the things which are non static, i.e. moving.

Thoughts?

[minz1]

Yeah, I've been mulling over that too. It's probably better that way, actually.

[rickbau5]

Sounds good, i'll throw something together real quick as a proof of concept.

[Vrekt]

I agree, btw i updated the tutorial what do you guys think. I need to include more but its the basic idea.

[rickbau5]

Alright, pushed something to basic-physics branch. It just adds entity velocity. Sorry it took a bit, had to re-setup my dev environment.

Example.

Obviously it's very simple at this point. But it's just to get the ball rolling. I was debating whether the world should handle adjusting velocity of entities based off of gravity or the entities themselves doing that. If it was done this way, then i'd propose adding a affectedByGravity flag to the Entity class, and add an implementation for updateEntity in the World class. Or there could be a new updatePhysics method. Many game engines differentiate between logic updates and physics updates.

[Vrekt]

Very nice I like that. I think entities should handle their own velocity stuff. Could cause problems with performance if the world is handling everything maybe.

[minz1]

My main concern is with how collisions would work. That's the largest problem with the physics. Any ideas?

[rickbau5]

@Vrekt maybe entites should handle setting their own velocity and what not, but then a centralized thing handle moving them around and checking collision like @minz1 brought up. Really if we want collision i think the only way to handle it is to have one class responsible for moving entities and checking collision. Otherwise the burden would be on the implementer for handling collision.

@minz1 to your question though, there's a BoundingBox class already which could be used to check collision.

Another thought - we need to look into adding the delta time to logic/physics calculations. From this article under point 1.2:

any game that has even basic physics (such as a platformer with jumping) will have wildly different behavior based on the frame rate.

Having delta time and including it in physics calculations solves that

[Vrekt]

Yeah Ill make a class soon that handles collisions where the user can call the methods within it when updateEntity is called.

[minz1]

@rickbau5 That sounds like the best way to me. I'll write a quick outline of how that could work and maybe start committing something basic and working to the physics branch when I get the time.

[thinkier]

Oh hi I'm a bit late to the party.

[thinkier]

Added a basic gravity object to basic-physics#3975b89. The object can probably expanded upon to handle all changing velocities based on gravity. - Or maybe motion can be another problem in another class.

[minz1]

I was under the impression that Gravity and such would be done under Entity.

EDIT: Also, for the way that object is written, perhaps Velocity or Force would be a better name.

[rickbau5]

I agree with @minz1 - that’s a velocity class disguised with the name gravity 😉 this class could be used as a property of entity, so this works for me.

[thinkier]

🤔 Fair enough. I would be inclined to name it Force and then make Direction point to something else, as motion isn't exclusively up/down/left/right/origin.

[thinkier]

Changed the Velocity class to point to a x and y instead of a Direction at b5b1c44

[rickbau5]

Want to make a merge request? You can actively continue to work on the branch but it would be a better place to have these conversations