Vectors

Yay! You have vectors too in Chelsea.js
Vectors are used to represent points in 2D space. They are used to represent the position of objects in 2D space. Vectors open a whole new frontier in the world of graphics.
Following is a list of all the functions you can use with vectors in Chelsea.js

Create Vector

createVector(x, y) is used to create a vector with components x and y in 2D space.

                
    createVector(x,y);

    var v = createVector(1,2);          // v= { x : 1, y : 2} 
            

Add Vectors

addVec(v1, v2) is used to add a vector to another vector.

                
    addVec(v1, v2);

    var v1 = createVector(1,2);
    var v2 = createVector(3,4);

    var v3 = addVec(v1, v2);              // v3 = { x : 4, y : 6} 
            

Subtract Vectors

subtractVec(v1, v2) is used to subtract a vector from another vector.

                
    subtractVec(v1, v2);

    var v1 = createVector(1,4);
    var v2 = createVector(6,2);

    var v3 = subtractVec(v1, v2);          // v3 = { x : -5, y : 2} 
            

Multiply Vector

multiplyVec(v, scalar) is used to multiply a vector to a scalar( magnitude ).

                
    multiplyVec(v, scalar);

    var v = createVector(1,2);
    var s = 3;

    var v2 = multiplyVec(v, s);            // v2 = { x : 3, y : 6} 
            

Divide Vector

divideVec(v, scalar) is used to divide a vector by a scalar( magnitude ).

                
    divideVec(v, scalar);

    var v = createVector(5,9);
    var s = 3;

    var v2 = divideVec(v, s);           // v2 = {x: 1.6666666666666667, y: 3} 
            

Get Distance between two vectors

distanceVec(v1, v2) is used to get the distance between heads of two vectors.

                
    distanceVec(v1, v2);

    var v1 = createVector(1,2);
    var v2 = createVector(3,4);

    var d = distanceVec(v1, v2);          // d = 2.8284271247461903 
    

Angle Between Vectors

angleBetween(v1, v2) is used to get the angle between two vectors.

        
    angleBetween(v1, v2);

    var v1 = createVector(1,2);
    var v2 = createVector(3,4);

    var a = angleBetween(v1, v2);          // a = 0.17985349979247847 
    

Rotate Vector

rotate(v, angle) is used to rotate a vector by an angle.

        
    rotate(v, angle);

    var v = createVector(1,2);

    var v2 = rotate(v, PI/2);            // v2 = { x : 2, y : -1} 
    

Magnitude

magnitude(v) is used to get the magnitude of a vector.
The magnitude is the length of the vector.

                
    magnitude(v);

    var v = createVector(3,4);

    var m = magnitude(v);                // m = 5 
            

Angle

angle(v) is used to get the angle( in radian ) of a vector with the positive x-axis.

                
    angle(v);

    var v = createVector(3,4);

    var a = angle(v);                    // a = 0.9272952180016122 
            

Normalized Vector

normalize(v) is used to get the normalized vector of a vector.
The normalized vector is a vector with the same direction as the original vector, but with a magnitude of 1.

                
    normalize(v);

    var v = createVector(3,4);

    var n = normalize(v);                // n = { x : 0.6, y : 0.8} 
            

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Dot Product

dotProduct(v1, v2) is used to get the dot product of two vectors.
The dot product is the sum of the products of the components of the vectors.

                
    dotProduct(v1, v2);

    var v1 = createVector(4,6);
    var v2 = createVector(3,4);

    var d = dotProduct(v1, v2);          // d = 36 
            

Cross Product

crossProduct(v1, v2) is used to get the cross product of two vectors.
The cross product in 2D space is the area of a parallelogram with the two vectors as sides and a negative value of the cross product simply signifies that the vectors are in clockwise order.

                
    crossProduct(v1, v2);

    var v1 = createVector(4,6);
    var v2 = createVector(3,4);

    var c = crossProduct(v1, v2);          // c = -2 
            

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Projection

projection(v1, v2) is used to get the projection of a vector(v1) onto another vector(v2).
The projection in simple words is the length of shadow that vector(v1) casts on vector(v2).

                
    projection(v1, v2);

    var v1 = createVector(4,6);
    var v2 = createVector(3,4);

    var p = projection(v1, v2);          // p = 2 
            

Reflection

reflect(v1, v2) is used to get the reflection of a vector(v1) in another vector(v2).
The reflection in simple words is the vector that is created by reflecting the vector(v1) in vector(v2).

                
    reflect(v1, v2);

    var v1 = createVector(1,6);
    var v2 = createVector(2,4);

    var r = reflect(v1, v2);          // r = { x : 4.2, y : 4.4} 
            

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Random Vector

randomVector() generates a normalized random vector.

                
    randomVector();  
    
            

Random Vector with Components

randomVectorComp(min, max) generates a vector with random components between minimum and maximum value.

                
    randomVectorComp(min, max);
    

Random Vector with Magnitude

randomVectorMagnitude(min, max) generates a random vector with the specified minimum and maximum values.

                
    randomVectorMagnitude(min, max);
            

Random Vector with Angle

randomVectorAngle(angle, min, max) generates a random vector with magnitude between m1, m2 at a given angle.
magnitude constraints are optional.

                
    randomVectorAngle(angle, min, max);

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