AThousandShips
commented
1 year ago No reason, but to have extra features in Godot.
This is not exactly what this question asks for, the question is why it is necessary to put in core, as opposed to as a plugin or add-on.
Adding a feature to core requires that it is something enough people will use to justify the work to create, maintain, and update it. This means that it either has to be very easy to do so, or that it is a sufficiently popular or needed feature.
This sounds like something that is very game specific and not something that's easy to do generically enough to cover all normal use cases, different styles, different requirements, different performance needs, etc.
ywmaa
RedMser
Zireael07
Describe the project you are working on
I know a similar issue exists, but I can't find it useful for describing the feature : https://github.com/godotengine/godot-proposals/issues/2082
a 3D Hero Shooter.
Describe the problem or limitation you are having in your project
no Destruction system.
Describe the feature / enhancement and how it helps to overcome the problem or limitation
Add DestructibleBody3D which Inherits RigidBody3D, and handles destruction system.
Describe how your proposal will work, with code, pseudo-code, mock-ups, and/or diagrams
The Setup
so the DestructibleBody3D will inherit RigidBody3D, it will have a specific function :
func damage(impact_point:Vector3=Vector3.ZERO, impact_force:float=1.0, impact_radius: float=1.0)also it will have a specific physics material containing the physical specs of the object like (material_bonds_strength, etc) and we will provide Default values for specific materials like (Wood, Glass, Metal).
also the node will show a warning in the editor that it requires a MeshInstance3D as a child (Needed for mesh slicing), and you will need to provide a material for the innner side of the MeshInstance3D that is going to be visible after the destruction happens.
How does work internally
Two Option That I want to add by default (Precomputed Destruction, Procedural Destruction). Both are opt-in features, I will explain how should each one work, and the merits of each one :
Precomputed Destruction
the editor will allow for generating precomputed Destruction Objects, so you will have a Voronoi Texture, and you set its values, the editor shows to you how it will cut the mesh.
then you press Compute Button somewhere (it could also be a built-in function so the developer can compute procedural assets)
Now the DestructibleBody3D will slice the mesh, and create the sliced MeshInstances3D + Collisions for each and adds a parent to them (RigidBody3D or DestructibleBody3D to them if developer chooses, but it will increase the cost of the original DestructibleBody3D), now we can either cache them or add them to the scene and hide them.
finally in game when something registers damage(), based on the provided values (material_specs + impact_force + impact_point + impact_radius) it will start adding normal force to either the RigidBody3D or DestructibleBody3D Childs (but in case of DestructibleBody3D it will add extra damage, after subtracting the force already taken by the parent DestructibleBody3D).
so now you should see your object exploding or something if you add enough force, else the object will break the specific part was damaged by the impact (I have an algorithm in mind, but I would like to first hear opinions on this approach).
Pros :
Better Performance compared to Procedural Destruction
Cons :
Not Totally acurate since it will be limited the Precomputed stage of it, it won't break anymore. OR, we can add an option to combine both, and make the first destruction use the precomputed then use Procedural Destruction.
Procedural Destruction
it will just do the same as Precomputed Destruction, but instead no Compute, the developer will provide GrayScale Texture that takes the shape of the destruction, and when something registers damage, it will do the slicing + creating collision shapes on the Fly
Pros :
Procedural so it will mimic a destruction more "Realistically". for example based on the provided texture we can just keep breaking the same object.
Imagine you add a texture that got the image of glass breaking :
it will use this image for the impact_position, so each type you hit Position X, it will slice the mesh from there in the shape of the provided texture, making the glass look like it is shattering
Cons :
Very Performance heavy as it does Realtime Mesh Generation + Collision Generation
Extra Features (Edit 0)
Recording Destruction Positions (For Reversing the Destruction) Opt-in feature
Multiplayer Sync (can be bandwidth heavy) Opt-in feature
If this enhancement will not be used often, can it be worked around with a few lines of script?
Yes it is not required to be part of the engine ,but actually any 3D game can find this useful, though I don't insist on this feature being part of Godot Directly, I will anyway do it for my game, I just here to see if the Godot Community wants this feature by default, and to discuss how to implement in such case, since from my search this feature is implemented in certain number of publicily available engines.
I will work on the feature sometime near for my game in Godot, I am just checking if it is accepted to do it as part of the engine instead of GD Extension
Is there a reason why this should be core and not an add-on in the asset library?
No reason, but to have extra features in Godot.
(Edit 0), can be useful for most 3D games, stylized or not, it is a physics feature for the engine, like SoftBody3D or SkeletonIK. and having it in core will make it maintained for every version onward until the engine developers decide to make it deprecated.