Lock mouse on game screen

Newbie & Debugging Questions
#1

Like in topic. Currently I am using Robot class to lock mouse on game screen, but this is not something I want, because it can’t do it smoothly (in the way user can’t see mouse “jumps”).

This is my code (inside main game loop):

if (xAbs<=Display.getX()+10) {
            robot.mouseMove(Display.getX()+10, yAbs);
            xAbs = MouseInfo.getPointerInfo().getLocation().x;
            yAbs = MouseInfo.getPointerInfo().getLocation().y;
        }
        if (yAbs<=Display.getY()+30) {
            robot.mouseMove(xAbs, Display.getY()+30);
            xAbs = MouseInfo.getPointerInfo().getLocation().x;
            yAbs = MouseInfo.getPointerInfo().getLocation().y;
        }
        if (xAbs>=Display.getX()+Display.getWidth()-10) {
            robot.mouseMove(Display.getX()+Display.getWidth()-10, yAbs);
            xAbs = MouseInfo.getPointerInfo().getLocation().x;
            yAbs = MouseInfo.getPointerInfo().getLocation().y;
        }
        if (yAbs>=Display.getY()+Display.getHeight()) {
            robot.mouseMove(xAbs, Display.getY()+Display.getHeight());
            xAbs = MouseInfo.getPointerInfo().getLocation().x;
            yAbs = MouseInfo.getPointerInfo().getLocation().y;
        }

Is there any way to do it “smoothly”?

#2

Well, at what rate is this code executing? And what do you mean by “jump”? Is the mouse cursor snapping back and forth between the desired position and the actual mouse position?

#3

It is executing about 60 times per second, but FPS may vary. By “jumping” I mean that when you want to leave “box” and move mouse fast enough, you can see how mouse leave game screen and comes back to it one frame later.

#4

Reposition the mouse cursor every frame, to the center of the viewport.

#5

What’s wrong with [icode]Mouse.setGrabbed(true);[/icode]?

#6

Now there is no mouse on screen.

#7

If the mouse is snapping on the mouse all the time, why would you want to draw the mouse anyways?

#8

I want to see cursor, but it must be “trapped” inside game screen.

#9

Why not hide the mouse with Mouse.setGrabbed(true), and then create a cursor texture, render it and make it follow the position of the mouse with Mouse.getX() and Mouse.getY() . Hope that helped! :slight_smile:

#10

As far as I know, this does only help a little bit, since the Mouse.getX() returns negative values very soon, if you move the mouse to the left. So if you’d draw a cursor directly at the Mouse.getX() position, it would be drawn outside the window.

What could possibly work is:
Set mouse to grabbed,
If the mouse is outside the window on the left, set the x position to the leftmost position,
If the mouse is outside the window on the top, set the y position to the topmost position,
If the mouse is outside the window on the right, set the x position to the rightmost position,
If the mouse is outside the window on the bottom, set the y position to the bottommost position,
Render mouse.

#11

Just use Mouse.getDX() and Mouse.getDY() to see how much the mouse traveled in the last frame :point:

#12

http://www.2shared.com/file/LaFt_tB_/CursorTestRUN.html
Download that. I hope that is what you mean. Made by me in 10 minuets! Source code: http://pastebin.java-gaming.org/e08aa0f4936 ;D

#13

Very big thanks, this is exacly the effect that I want to obtain. :wink: