dreemgl/system/shaderlib/mathlib.js

DreemGL is an open-source multi-screen prototyping framework for mediated environments, with a visual editor and shader styling for webGL and DALi runtimes written in JavaScript. As a toolkit for gpu-accelerated multiscreen development, DreemGL includes

/* DreemGL is a collaboration between Teeming Society & Samsung Electronics, sponsored by Samsung and others.
   Copyright 2015-2016 Teeming Society. Licensed under the Apache License, Version 2.0 (the "License"); You may not use this file except in compliance with the License.
   You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing,
   software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and limitations under the License.*/

define(function(require, exports){
	this.RAD = '1.'
	this.DEG = '0.017453292519943295'
	this.PI = '3.141592653589793'
	this.PI2 = '6.283185307179586'
	this.E = '2.718281828459045'
	this.LN2 = '0.6931471805599453'
	this.LN10 = '2.302585092994046'
	this.LOG2E = '1.4426950408889634'
	this.LOG10E = '0.4342944819032518'
	this.SQRT_1_2 = '0.70710678118654757'
	this.SQRT2 = '1.4142135623730951'

	exports.rotate2d = function(v, angle){
		var cosa = cos(angle)
		var sina = sin(angle)
		return vec2(v.x * cosa - v.y * sina, v.x * sina + v.y * cosa)
	}

	exports.bezier2d = function(p0, p1, p2, p3, t){
		var t2 = t*t;
		var t3 = t2*t;
		var it = (1-t);
		var it2 = it*it;
		var it3 = it2*it;
	//	return p0 + t*vec2(1,0);
		var pos = p0 * it3  + p1*3*t*it2 + p2 * 3*it*t2 +  p3* t3;
		var deriv = -3.0 * p0 * it2 + 3 * p1 * (it2-2*t*it) + 3 * p2 *( -t2 + it * t * 2) + 3 * p3 * t2;
		deriv = normalize(deriv);
		return vec4(pos.x, pos.y, deriv.x, deriv.y);
    }

		exports.odd = function(f){
			if (mod(f, 2.0) == 0.0)
				return true
			else
				return false
		}

		exports.even = function(f){
			if (mod(f, 2.0) == 0.0)
				return false
			else
				return true
		}

})