如何获得Unity的帧率独立触摸位置？

Question

I am to make a mobile painting game in Unity and I've encountered a serious problem: the Input class in Unity is frame-dependent. Thus I can't get the position of touch frequent enough to make my application draw smoothly; as a result I get something like just points on the background, not connected between each other.

I tried to just connect the points that are detected in Unity, and than my result was just the same points connected with lines, of course. I was trying this in Unity Editor with about 180-200 fps, and on mobile phone with 30-50 fps it looks even worse. I expect that I have to get the touch positions somehow in android studio or Xcode, and only then use them in my C# code in Unity editor.

Am I thinking right to use extern from Unity tools, or there is another easier way to do it directly in Unity? If there is none and I am right, can somebody give me some links to guides/tutorials how to do it and integrate it with Unity? I have never worked outside of Unity and have no experience in integration some external tools with it.

Note: I've tried FixedUpdate without any luck - it doesn't matter how often I try to get the position variables, it is about how often they are updated; I also tried Event.current.mousePosition(in unity editor) in OnGUI method, but it also gave me no difference.

Upd: As I have already said, I need to get positions more frequently than the Input class gives me. It updates not fast enough! Here's what I get without connecting the points. The image shows the mousePosition detection frequency in 180-200 fps. On phones it is even slower!

Upd: Here is my simplified code.

void Draw() //this method is invoked every frame
     {
         //some calculations of x and y based on Input variables
         currentMousePosition = new Vector2( x, y); //current mouse position on sprite
         if(currentMousePosition != previousMousePosition)
             {
                 while(currentMousePosition != previousMousePosition)
                 {
                 mySprite.texture.SetPixels((int)previousMousePosition.x, (int)previousMousePosition.y, 3,3, myColorArray);
                                 if (currentFrameMousePos.x > previousFrameMousePos.x)
                                     previousFrameMousePos.x++;
                                 if (currentFrameMousePos.x < previousFrameMousePos.x)
                                     previousFrameMousePos.x--;
                                 if (currentFrameMousePos.y > previousFrameMousePos.y)
                                     previousFrameMousePos.y++;
                                 if (currentFrameMousePos.y < previousFrameMousePos.y)
                                     previousFrameMousePos.y--;
                   }
             } else mySprite.texture.SetPixels((int)currentMousePosition.x, (int)currentMousePosition.y, 3,3, myColorArray);
             previousMousePosition = currentMousePosition;
     }
     //mySprite.texture.Apply() is invoked independently in another place to improve performance

Answer 1

The issue is, it is not possible to queue up touch positions that occurred mid frame so by "Quickly" sliding your finger you will miss certain texels on your image. You should look at this line formula Bresenham's line algorithm . This is super fast, and all integer math. Inside your Update() function call this method.

    Vector2 oldPoint;
    public void UpdateDrawPoint(Vector2 newPoint){
        BresenhamLine(newPoint, oldPoint);
        oldPoint = newPoint;
    }