Supako: 2D Geometry Thing for Godot

Supako is a 2D geometry drawing system/thing addon for Godot 4. It do shapes.

NOTE: This project is in an experimental / prototype state. I wouldn't recommend using this in production, but you might find some bits useful or interesting...

What's it for?

• More complicated stuff than Godot's Polygon2D
• 2D games that aren't tile-based
• Semi-procedural 2D geometry
• Draw many unique shapes (re-)using a shared pattern

Features

• Fine-grained rendering / appearance control
• Efficient collision shape extraction
• Effect system provides modularity and extensibility
• Boolean operations to build complex shapes
• Select segments used by effects by surface normal (angle ranges)

Incomplete/Unimplemented

• Open paths (polylines) and effects to work with them
• Logical materials / regions
• Attach arbitrary metadata/userdata to geometry, vertex groups
• Generic geometry masking / selection -- mask geometry accessible to any effect
• More robust polygon clipping operations (and support for holes)
• Overridable effect configuration -- optionally set effect parameters in host shape (rather than in the Effect Resource)
• Multi/meta effects -- new effects via composition

Usage | How it works

Supako drawings are constructed in the Godot scene tree using shape nodes (SpkoShape).

• Create a drawing by adding any SpkoShape-derived node to a scene.
• Note that SpkoShape itself is a base class and doesn't provide any way to add geometry manually.
  • SpkoPath is a shape node with a manually editable polygon. It can be edited in the 2D scene editor, in a similar way to Godot's built-in Polygon2D.
• Child shapes can be merged with their parent by inclusion or via boolean/clipping operations, depending on the merge operation property of the child.

Effects are a modular way to add functionality to shapes.

• Each shape's geometry gets processed by its effects chain
• Effects are processed in order. This can be taken advantage of to e.g. extract simplified collision shapes before bevelling the corners.
• Create new effects by extending SpkoEffect (a type of Resource)

Where possible, features are implemented as effects to avoid bloating SpkoShape. Built-in effects include:

• Fill Painter draws polygon interior
• Stroke Painter draws polygon edges
• Collision Shape builds collision shape/s and a static body or area
• Corners adds chamfers/fillets to sharp corners
• Decorator adds decorations/sprites to surfaces