shapes.go

package coll

import (
	"github.com/setanarut/v"
)

// OBB represents an Oriented Bounding Box
type OBB struct {
	Pos   v.Vec   // Center position of the box.
	Half  v.Vec   // Half-extents (half dimensions) from the center.
	Angle float64 // Rotation angle from center (Pos). Unit in radians. (Clockwise)
}

// AABB represents an Axis-Aligned Bounding Box.
type AABB struct {
	Pos  v.Vec // Center position of the box.
	Half v.Vec // Half-extents (half dimensions) from the center.
}

// Returns the left x-coordinate of the box.
func (a *AABB) Left() float64 { return a.Pos.X - a.Half.X }

// Returns the right x-coordinate of the box.
func (a *AABB) Right() float64 { return a.Pos.X + a.Half.X }

// Returns the top y-coordinate of the box (usually smaller y).
func (a *AABB) Top() float64 { return a.Pos.Y - a.Half.Y }

// Returns the bottom y-coordinate of the box (usually larger y).
func (a *AABB) Bottom() float64 { return a.Pos.Y + a.Half.Y }

// Sets the left x-coordinate and updates Pos.X accordingly.
func (a *AABB) SetLeft(l float64) { a.Pos.X = l + a.Half.X }

// Sets the right x-coordinate and updates Pos.X accordingly.
func (a *AABB) SetRight(r float64) { a.Pos.X = r - a.Half.X }

// Sets the top y-coordinate and updates Pos.Y accordingly.
func (a *AABB) SetTop(t float64) { a.Pos.Y = t + a.Half.Y }

// Sets the bottom y-coordinate and updates Pos.Y accordingly.
func (a *AABB) SetBottom(b float64) { a.Pos.Y = b - a.Half.Y }

// Returns the total width (X dimension) of the box.
func (a *AABB) Width() float64 { return a.Half.X * 2 }

// Returns the total height (Y dimension) of the box.
func (a *AABB) Height() float64 { return a.Half.Y * 2 }

// Returns top-left point
func (a *AABB) Min() v.Vec { return v.Vec{a.Left(), a.Top()} }

// Returns bottom-right point
func (a *AABB) Max() v.Vec { return v.Vec{a.Right(), a.Bottom()} }

// Circle represents a circular bounding volume.
type Circle struct {
	Pos    v.Vec   // Center position of the circle.
	Radius float64 // The radius of the circle.
}

// Segment shape with A and B points.
type Segment struct {
	A, B v.Vec
}

// NewAABB returns new AABB
func NewAABB(centerX, centerY, halfWidth, halfHeight float64) *AABB {
	return &AABB{Pos: v.Vec{centerX, centerY}, Half: v.Vec{halfWidth, halfHeight}}
}

// NewCircle returns new Circle
func NewCircle(x, y, radius float64) *Circle {
	return &Circle{Pos: v.Vec{x, y}, Radius: radius}
}

// NewSegment returns new Segment
func NewSegment(ax, ay, bx, by float64) *Segment {
	return &Segment{A: v.Vec{ax, ay}, B: v.Vec{bx, by}}
}