utils.ts

export function vecAdd(vecOne: Array<number>, vecTwo: Array<number>){
    let vecSum: Array<number> = vecOne;

    vecSum[0] += vecTwo[0];
    vecSum[1] += vecTwo[1];
    vecSum[2] += vecTwo[2];

    return vecSum;
}

export function vecSubtract(vecOne: Array<number>, vecTwo: Array<number>){
    let vecSubt: Array<number> = vecOne;

    vecSubt[0] -= vecTwo[0];
    vecSubt[1] -= vecTwo[1];
    vecSubt[2] -= vecTwo[2];

    return vecSubt;
}

export function vecMultiply(vecOne: Array<number>, factor: number){
    vecOne[0] *= factor;
    vecOne[1] *= factor;
    vecOne[2] *= factor;

    return vecOne;
}

export function vecLength(vec: Array<number>){
    let length: number;
    length = Math.sqrt(vec[0]*vec[0] + vec[1]*vec[1] + vec[2]*vec[2]);
    return length;
}

export function vecNormalize(vec: Array<number>){
    let computedLength = vecLength(vec);
    if(computedLength == 0){computedLength = 1};

    let inverse = 1 / computedLength;

    let normalized: Array<number> = new Array;

    normalized[0] = vec[0] * inverse;
    normalized[1] = vec[1] * inverse;
    normalized[2] = vec[2] * inverse;

    return normalized;
}

export function vecDotProduct(vecOne: Array<number>, vecTwo: Array<number>){
    let dotProduct = vecOne[0]*vecTwo[0] + vecOne[1]*vecTwo[1] + vecOne[2]*vecTwo[2];
    return dotProduct;
}

export function vecAngle(vecOne: Array<number>, vecTwo: Array<number>){
    //calculate radiant
    let radiant = Math.acos(vecDotProduct(vecOne, vecTwo) / (vecLength(vecOne) * vecLength(vecTwo)))

    //convert into degrees
    let degrees = radiant * 180 / Math.PI;
    return degrees;
}

export function vecCrossProduct(vecOne: Array<number>, vecTwo: Array<number>){
    let crossProduct : Array<number> = new Array;

    crossProduct[0] = vecOne[1]*vecTwo[2] - vecOne[2]*vecTwo[1];
    crossProduct[1] = vecOne[2]*vecTwo[0] - vecOne[0]*vecTwo[2];