Class: RGame::Engine::CircleCollider

Inherits:
Object
  • Object
show all
Defined in:
lib/rgame/engine/circle_collider.rb

Overview

A circular collision shape, the sibling of CollisionBox for entities that rotate (rocks, ship): a circle is rotation-invariant, so a spinning rock needs no per-frame box recompute. The collider owns only the radius; the entity owns its centre position. Pure logic; no graphics.

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(radius:) ⇒ CircleCollider

Returns a new instance of CircleCollider.



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# File 'lib/rgame/engine/circle_collider.rb', line 20

def initialize(radius:)
  @radius = radius
end

Instance Attribute Details

#radius ⇒ Object (readonly)

Returns the value of attribute radius.



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# File 'lib/rgame/engine/circle_collider.rb', line 10

def radius
  @radius
end

Class Method Details

.overlap?(x1, y1, r1, x2, y2, r2) ⇒ Boolean

Squared-distance overlap test (no sqrt): true when two circles touch.

Returns:

  • (Boolean) 


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# File 'lib/rgame/engine/circle_collider.rb', line 13

def self.overlap?(x1, y1, r1, x2, y2, r2)
  dx = x2 - x1
  dy = y2 - y1
  sum = r1 + r2
  (dx * dx) + (dy * dy) <= sum * sum
end

Instance Method Details

#aabb(cx, cy) ⇒ Object

Bounding AABB [x, y, w, h] for a circle centred at (cx, cy) — what the spatial hash buckets on.



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# File 'lib/rgame/engine/circle_collider.rb', line 26

def aabb(cx, cy)
  d = @radius * 2
  [cx - @radius, cy - @radius, d, d]
end