// C++ port of this demo code: http://jsfiddle.net/MadLittleMods/thcstaay/
float approximateArcLengthOfBezierCurve(size_t controlPointListSize, Vector2 *controlPointListPointer, int resolution, Vector2 (*pointOnCurveFunc)(size_t, Vector2*, float)) {
    // Resolution is the number of segments we use
    resolution = resolution ? resolution : 500;

    float resultantArcLength = 0;
    float arcLengthMap[resolution+1];


    Vector2 controlPointList[controlPointListSize];
    for(int i = 0; i < controlPointListSize; i++) {
        controlPointList[i] = controlPointListPointer[i];
    }

    Vector2 prevPoint = controlPointList[0];
    Vector2 nextPoint;
    int mapIndex = 0;
    for(int i = 0; i < resolution; i++) {
        float t = clamp(i*(1/resolution), 0, 1);
        nextPoint = (*pointOnCurveFunc)(controlPointListSize, controlPointList, t);
        resultantArcLength += distance(prevPoint, nextPoint);
        prevPoint = nextPoint;

        arcLengthMap[mapIndex] = {
            t: t,
            arcLength: resultantArcLength
        };
        mapIndex++;
    }
    // Last stretch to the endpoint
    nextPoint = controlPointList[controlPointList.length-1];
    resultantArcLength += distance(prevPoint, nextPoint);
    arcLengthMap[mapIndex] = {
        t: 1,
        arcLength: resultantArcLength
    };
    mapIndex++;

    return {
        arcLength: resultantArcLength,
        arcLengthMap: arcLengthMap
    };
}

float distance(Vector2 p0, Vector2 p1) {
    return sqrt(pow(p1.x-p0.x, 2) + pow(p1.y-p0.y, 2));
}

float clamp(float val, float minVal, float maxVal)
{
    float tempMax = max(val, minVal);
    return min(tempMax, maxVal);
}