Implement `draw_shape` function to create procedural 2D/3D geometric primitives

[dklassic]

Problem or limitation

I've been working on minimalist visual style games and if engines can have (more) built-in 2D/3D geometric primitives rendering function, it would make making the games I've been doing a breeze.

I've came from Unity which also doesn't have this feature and I have been using a plugin that does some of that 2D/3D primitive rendering called Shapes since forever, and this is what my project looked like:

I think it would be pretty neat to have a built-in draw_shape function to procedurally create 2D/3D geometric primitives would be very helpful. I've been recently working to build a plugin in Godot to do just that and I had some success so I figure it shouldn't be that hard to build it into the engine and I would expect a lot of use out of it:

Proposed improvement

Similar to existing _draw() commands, something like void draw_shape(Shape shape, ShapeStyle style, Vector3 position, Quaternion rotation) under _draw(), or a retained mode ShapeHandle draw_shape(Shape shape, ShapeStyle style, Vector3 position, Quaternion rotation) would be nice.

Potentially having a Node that can simply author any shape would also be nice, here's one I built for my plugin:

Proposal review

• Yes, this proposal is highly specific and actionable.

[Calinou]

• Related to Add singletons for 2D and 3D debug drawing #5196.

I think the current set of PrimitiveMeshes we have is pretty solid already. There's not much I feel is really missing, especially when you can use TubeTrailMesh to draw cylinders with an arbitrary curve profile.

There's also CSGPolygon3D for more complex shape drawing.

For 2D shape drawing, see #1126.

[dklassic]

• Related to Add singletons for 2D and 3D debug drawing #5196.

I think the current set of PrimitiveMeshes we have is pretty solid already. There's not much I feel is really missing, especially when you can use TubeTrailMesh to draw cylinders with an arbitrary curve profile.

There's also CSGPolygon3D for more complex shape drawing.

For 2D shape drawing, see #1126.

Thanks for the pointers! I was hoping for something a lot more advanced while being more "production-useful" and more than just for debugging, for example line/rounded polyline/dashed line support:

Certainly Polygon2D and CSGPolygon3D are a thing, but they are also a lot more cumbersome to use than what normally developers might just want a "nice looking shape placed here".

And features like:

• Stencil State
• Depth State

• Rounded Mesh (Rounded Cylinder/Prism/Rectangle/RegularPolygon etc.)
• Color lerping

I think these are some low hanging fruit that people can get a lot of mileage out of it to be able to create really nice looking games easily.

Just some thoughts. I kind of really wanted these when I started out making games some years ago :/ (above images are all from my plugin using MultiMesh to create massive primitives with extremely low cost, feels like these functionality should be implemented from ground up within engine tho)

[Calinou]

for example line/rounded polyline/dashed line support:

This could be handled by a future Line3D class (godotengine/godot#117107 implemented the groundwork to make this possible). Textured lines can be used to make them dashed.

[CoolStopCode]

It was already mentioned but I think the approach of #1126 is a better route. Instead of static draw functions a set of 2D primitive shape nodes would fit Godot better. CSG primitives already exist and work fine for 3D shape drawing.

Could you link your plugin? Looks awesome.

[dklassic]

It was already mentioned but I think the approach of #1126 is a better route. Instead of static draw functions a set of 2D primitive shape nodes would fit Godot better. CSG primitives already exist and work fine for 3D shape drawing.

Could you link your plugin? Looks awesome.

The slight difference (that I hope to implement in the end) is that all of this can supposedly be reworked into efficient batched rendering with a lot of knobs to turns, as is it feels like the simple need of "I need to draw a shape here" is being split between multiple APIs and tools for no apparent reason hence the draw_shape generic function. And yes also single Shape node might be more helpful than trying to know what actual shapes are supported: to put it simply I didn't really know where to find all supported shape node.

Edit: uh I'm writing this badly so let me do some rephrasing:

• A generic shape node would also be great! That's one of the issue I had with Godot because I can't find the things I need.
• I also would hope to have a very efficiently batched api to interact with, especially for allowing rendering through code without the need to interact with the scene itself. For what I was making I need to draw thousands of generic primitives which is very slow if I do it with Nodes.
• It would be nice if the proposed generic shape node could optionally opt into the efficiently batched pipeline to be rendered outside of scene view.

As for the plugin I'm at the point of "wait, isn't this more useful if it can just get into the engine?" since it is quite generically applicable so that's why I'm here asking around. If this seem more like something that should exists outside of the engine then I'll probably continue working on it, find some testers etc.

[dklassic]

Anyways I just hosted my addon on itch, if anyone wanted to check it out. tagging @CoolStopCode would love to hear your thoughts