I’m working on adding image drawing and erasing capabilities using OpenCV in C++. But the problem is that it’s not fluid at all, the drawing only appears when I release the mouse and it appears very straight, as you can see in this video

#include <iostream>
#include <opencv2/opencv.hpp>

using namespace std;
using namespace cv;

Mat originalImage;
Mat currentImage;
Mat tempImage;
bool isDrawing = false;
bool isErasing = false;
Point startPoint;

void updateImage() {
    addWeighted(originalImage, 1.0, tempImage, 1.0, 0.0, currentImage);
    imshow("Drawing", currentImage);
}

static void drawCallback(int event, int x, int y, int flags, void* param) {
    switch (event) {
        case EVENT_LBUTTONDOWN:
            if (flags & EVENT_FLAG_CTRLKEY) {
                isErasing = true;
                startPoint = Point(x, y);
            }
            else {
                isDrawing = true;
                startPoint = Point(x, y);
            }
            break;
        case EVENT_MOUSEMOVE:
            if (isDrawing) {
                line(tempImage, startPoint, Point(x, y), Scalar(0, 0, 255), 8);
                startPoint = Point(x, y);
                updateImage();
            }
            else if (isErasing) {
                line(tempImage, startPoint, Point(x, y), Scalar(0, 0, 0), 8);
                startPoint = Point(x, y);
                updateImage();
            }
            break;
        case EVENT_LBUTTONUP:
            isDrawing = false;
            isErasing = false;
            break;
    }
}

int main()
{
    string imagePath = "C:/Users/Yuri/Pictures/space.jpg";

    originalImage = imread(imagePath, IMREAD_COLOR);

    resize(originalImage, originalImage, { 1000, 500 }, 0, 0, INTER_NEAREST);

    currentImage = Mat::zeros(originalImage.size(), originalImage.type());

    tempImage = currentImage.clone();

    namedWindow("Drawing");

    updateImage();

    setMouseCallback("Drawing", drawCallback, nullptr);

    while (1) {
        imshow("Drawing", currentImage);

        if (waitKey(0) == 27)
            break;
    }

    destroyAllWindows();
    return 0;
}

I’m looking to speed things up and make the drawing and erasing smoother. Any tips or tricks on optimizing my code or using specific OpenCV features would be awesome.
When I don’t use any images I don’t need to use addWeighted, and so it becomes extremely fluid, but the idea is to draw in images and I believe that using addWeighted is what is causing the slowness, but I haven’t found ways to do what I need without it