gokg

README

GOKG

aka "Golang kjkrol Geometry"

GOKG is a Go toolkit focused on practical 2D computational geometry.
It centres on two core primitives — Vec for points and directions, and axis-aligned bounding boxes (BoundingBox) — together with a plane-aware overlay (PlaneBox) that transforms, combines, and analyses them.
The library also models both finite and infinite planes, providing operations that help classify, intersect, and project geometric entities.
The focus remains purely on mathematical geometry; rendering or UI concerns live in neighbouring packages.

PlaneBox boundary handling

• Finite planes clamp plane boxes to the viewport while keeping their size consistent, so expansions never bleed beyond the defined world.
• Cyclic planes automatically wrap plane boxes that cross an edge and split them into fragments (Fragments()) that continue on the opposite side, making toroidal worlds easy to model.
• The helper methods Translate and Expand renormalise plane boxes on every call, updating cached fragments and ensuring touch/collision queries remain accurate without extra bookkeeping.

Usage example

package main

import (
	"fmt"

	"github.com/kjkrol/gokg/pkg/geometry"
)

func main() {
	position := geometry.NewVec(3.0, 4.0)
	velocity := geometry.NewVec(1.5, -0.5)

	next := position.Add(velocity)

	region := geometry.NewPlaneBox(position, 2.0, 2.0)

	plane := geometry.NewBoundedPlane[float64](100, 100)
	plane.Translate(&region, velocity)

	fmt.Printf("next position: %v\n", next)
	pointRegion := geometry.NewPlaneBox(next, 0, 0)
	fmt.Printf("region contains next? %v\n", region.Contains(pointRegion))
}

For more scenarios, browse the example-based tests under pkg/geometry, which double as runnable documentation.

Projects using GOKG

• gokq — quadtree utilities that rely on Vec, BoundingBox, and PlaneBox operations.
• gokx — graphical experiments that consume the geometric primitives from this package.