98 lines
2.4 KiB
JavaScript
98 lines
2.4 KiB
JavaScript
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DWE.Math = {}
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DWE.Math.random = function (i,j) {
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return Math.floor(Math.random() * j) + i
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}
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DWE.Math.lerp = function (v0, v1, t) {
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return (1 - t) * v0 + t * v1
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}
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DWE.Math.reverseLerp = function (v0, v1, t) {
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return 1.0 / ((v1 - v0) * t)
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}
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DWE.Math.intersectsBox = function (ax, ay, aw, ah, bx, by, bw, bh) {
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return (Math.abs(ax - bx) * 2 <= (aw + bw)) &&
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(Math.abs(ay - by) * 2 <= (ah + bh))
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}
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DWE.Math.intersects2Box = function (a, b) {
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return (Math.abs(a.x - b.x) * 2 <= (a.width + b.width)) &&
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(Math.abs(a.y - b.y) * 2 <= (a.height + b.height))
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}
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DWE.Math.clamp = function (val, min, max) {
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return Math.max(min, Math.min(max, val))
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}
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// Two-dimensional vector
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DWE.Math.Vector2 = class {
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constructor (x, y) {
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this.x = x
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this.y = y
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}
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get magnitude () {
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return Math.abs(Math.sqrt((this.x * this.x) + (this.y * this.y)))
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}
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normalize () {
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var len = this.magnitude
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this.x /= len
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this.y /= len
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}
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distance (vec) {
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if (!(vec instanceof DWE.Math.Vector2)) throw new Error('Distance function takes another Vector2 as an argument.')
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return Math.abs(Math.sqrt(Math.pow(vec.x - this.x, 2) + Math.pow(vec.y - this.y, 2)))
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}
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}
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// A box.
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DWE.Math.Box2 = class {
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constructor (x, y, w, h) {
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this.x = x
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this.y = y
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this.width = w
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this.height = h
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}
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intersectsBox (box) {
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if (!(box instanceof DWE.Math.Box2)) throw new Error('Intersection function takes another Box2 as an argument.')
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return DWE.Math.intersects2Box(this, box)
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}
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intersectsCircle (circle) {
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if (!(circle instanceof DWE.Math.Circle)) throw new Error('Intersection function takes another Circle as an argument.')
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var circleDistance = new DWE.Math.Vector2(Math.abs(circle.x - this.x), Math.abs(circle.y - this.y))
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if (circleDistance.x > (this.width/2 + circle.r)) return false
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if (circleDistance.y > (this.height/2 + circle.r)) return false
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if (circleDistance.x <= (this.width/2)) return true
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if (circleDistance.y <= (this.height/2)) return true
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var cornerDistance_sq = Math.pow(circleDistance.x - this.width/2, 2) +
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Math.pow(circleDistance.y - this.height/2, 2)
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return (cornerDistance_sq <= Math.pow(circle.r, 2))
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}
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}
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// A circle.
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DWE.Math.Circle = class {
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constructor (x, y, r) {
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this.x = x
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this.y = y
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this.r = r
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}
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get radius () {
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return this.r
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}
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}
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