API Docs for: GoblinPhysics
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File: src\classes\BroadPhases\BasicBroadphase.js

  1. /**
  2.  * Performs a n^2 check of all collision objects to see if any could be in contact
  3.  *
  4.  * @class BasicBroadphase
  5.  * @constructor
  6.  */
  7. Goblin.BasicBroadphase = function() {
  8. 	/**
  9. 	 * Holds all of the collision objects that the broadphase is responsible for
  10. 	 *
  11. 	 * @property bodies
  12. 	 * @type {Array}
  13. 	 */
  14. 	this.bodies = [];
  15.  
  16. 	/**
  17. 	 * Array of all (current) collision pairs between the broadphase's bodies
  18. 	 *
  19. 	 * @property collision_pairs
  20. 	 * @type {Array}
  21. 	 */
  22. 	this.collision_pairs = [];
  23. };
  24.  
  25. /**
  26.  * Adds a body to the broadphase for contact checking
  27.  *
  28.  * @method addBody
  29.  * @param body {MassPoint|RigidBody} body to add to the broadphase contact checking
  30.  */
  31. Goblin.BasicBroadphase.prototype.addBody = function( body ) {
  32. 	this.bodies.push( body );
  33. };
  34.  
  35. /**
  36.  * Removes a body from the broadphase contact checking
  37.  *
  38.  * @method removeBody
  39.  * @param body {MassPoint|RigidBody} body to remove from the broadphase contact checking
  40.  */
  41. Goblin.BasicBroadphase.prototype.removeBody = function( body ) {
  42. 	var i,
  43. 		body_count = this.bodies.length;
  44.  
  45. 	for ( i = 0; i < body_count; i++ ) {
  46. 		if ( this.bodies[i] === body ) {
  47. 			this.bodies.splice( i, 1 );
  48. 			break;
  49. 		}
  50. 	}
  51. };
  52.  
  53. /**
  54.  * Checks all collision objects to find any which are possibly in contact
  55.  *  resulting contact pairs are held in the object's `collision_pairs` property
  56.  *
  57.  * @method predictContactPairs
  58.  */
  59. Goblin.BasicBroadphase.prototype.predictContactPairs = function() {
  60. 	var i, j,
  61. 		object_a, object_b,
  62. 		bodies_count = this.bodies.length;
  63.  
  64. 	// Clear any old contact pairs
  65. 	this.collision_pairs.length = 0;
  66.  
  67. 	// Loop over all collision objects and check for overlapping boundary spheres
  68. 	for ( i = 0; i < bodies_count; i++ ) {
  69. 		object_a = this.bodies[i];
  70.  
  71. 		for ( j = 0; j < bodies_count; j++ ) {
  72. 			if ( i <= j ) {
  73. 				// if i < j then we have already performed this check
  74. 				// if i === j then the two objects are the same and can't be in contact
  75. 				continue;
  76. 			}
  77.  
  78. 			object_b = this.bodies[j];
  79.  
  80. 			if ( object_a.mass === Infinity && object_b.mass === Infinity ) {
  81. 				// Two static objects aren't considered to be in contact
  82. 				continue;
  83. 			}
  84.  
  85.             if ( object_a.aabb.intersects( object_b.aabb ) )
  86.             {
  87. 				this.collision_pairs.push([ object_a, object_b ]);
  88. 			}
  89. 		}
  90. 	}
  91. };
  92.  
  93. /**
  94.  * Checks if a ray segment intersects with objects in the world
  95.  *
  96.  * @method rayIntersect
  97.  * @property start {vec3} start point of the segment
  98.  * @property end {vec3{ end point of the segment
  99.  * @return {Array<RayIntersection>} an unsorted array of intersections
  100.  */
  101. Goblin.BasicBroadphase.prototype.rayIntersect = function( start, end ) {
  102. 	var bodies_count = this.bodies.length,
  103. 		i, body,
  104. 		intersections = [];
  105. 	for ( i = 0; i < bodies_count; i++ ) {
  106. 		body = this.bodies[i];
  107. 		if ( body.aabb.testRayIntersect( start, end ) ) {
  108. 			body.rayIntersect( start, end, intersections );
  109. 		}
  110. 	}
  111.  
  112. 	return intersections;
  113. };
  114.