File: src/geometry/Bounds.js
/**
* The `Matter.Bounds` module contains methods for creating and manipulating axis-aligned bounding boxes (AABB).
*
* @class Bounds
*/
var Bounds = {};
module.exports = Bounds;
(function() {
/**
* Creates a new axis-aligned bounding box (AABB) for the given vertices.
* @method create
* @param {vertices} vertices
* @return {bounds} A new bounds object
*/
Bounds.create = function(vertices) {
var bounds = {
min: { x: 0, y: 0 },
max: { x: 0, y: 0 }
};
if (vertices)
Bounds.update(bounds, vertices);
return bounds;
};
/**
* Updates bounds using the given vertices and extends the bounds given a velocity.
* @method update
* @param {bounds} bounds
* @param {vertices} vertices
* @param {vector} velocity
*/
Bounds.update = function(bounds, vertices, velocity) {
bounds.min.x = Infinity;
bounds.max.x = -Infinity;
bounds.min.y = Infinity;
bounds.max.y = -Infinity;
for (var i = 0; i < vertices.length; i++) {
var vertex = vertices[i];
if (vertex.x > bounds.max.x) bounds.max.x = vertex.x;
if (vertex.x < bounds.min.x) bounds.min.x = vertex.x;
if (vertex.y > bounds.max.y) bounds.max.y = vertex.y;
if (vertex.y < bounds.min.y) bounds.min.y = vertex.y;
}
if (velocity) {
if (velocity.x > 0) {
bounds.max.x += velocity.x;
} else {
bounds.min.x += velocity.x;
}
if (velocity.y > 0) {
bounds.max.y += velocity.y;
} else {
bounds.min.y += velocity.y;
}
}
};
/**
* Returns true if the bounds contains the given point.
* @method contains
* @param {bounds} bounds
* @param {vector} point
* @return {boolean} True if the bounds contain the point, otherwise false
*/
Bounds.contains = function(bounds, point) {
return point.x >= bounds.min.x && point.x <= bounds.max.x
&& point.y >= bounds.min.y && point.y <= bounds.max.y;
};
/**
* Returns true if the two bounds intersect.
* @method overlaps
* @param {bounds} boundsA
* @param {bounds} boundsB
* @return {boolean} True if the bounds overlap, otherwise false
*/
Bounds.overlaps = function(boundsA, boundsB) {
return (boundsA.min.x <= boundsB.max.x && boundsA.max.x >= boundsB.min.x
&& boundsA.max.y >= boundsB.min.y && boundsA.min.y <= boundsB.max.y);
};
/**
* Translates the bounds by the given vector.
* @method translate
* @param {bounds} bounds
* @param {vector} vector
*/
Bounds.translate = function(bounds, vector) {
bounds.min.x += vector.x;
bounds.max.x += vector.x;
bounds.min.y += vector.y;
bounds.max.y += vector.y;
};
/**
* Shifts the bounds to the given position.
* @method shift
* @param {bounds} bounds
* @param {vector} position
*/
Bounds.shift = function(bounds, position) {
var deltaX = bounds.max.x - bounds.min.x,
deltaY = bounds.max.y - bounds.min.y;
bounds.min.x = position.x;
bounds.max.x = position.x + deltaX;
bounds.min.y = position.y;
bounds.max.y = position.y + deltaY;
};
})();