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Thread: Rectangle keeps getting faster

  1. #1
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    Default Rectangle keeps getting faster

    obstacleX = (int) (obstacleX - 0.1);
    if(obstacleX <= 0){
    obstacleX = 600;
    }
    repaint();

    Thats my code, and the rectangle (ObstacleX is the X cordinate for the rectangle) goes fine on the first few times across the screen, then starts to go hyperspeed....Please help!


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    Default Re: Rectangle keeps getting faster

    Try debugging the code by adding some println() statements to print out changes to the variables that control the speed of the rectangle. The print out should show you where the code is going wrong. Be sure to add an id String with the print so you can tell which println() printed the output. A list of numbers is hard to read sometimes without labels saying where they were printed.
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: Rectangle keeps getting faster

    Um, I am very new lol. I have added a Levels thing in my f3 menu, where every 10 times a rectangle passes, it goes up. That number is slow at first (How I want it) and then it gets faster and stays the same.

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    Default Re: Rectangle keeps getting faster

    What did the print outs show?
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: Rectangle keeps getting faster

    Like I said, they showed the levels going faster and faster until it went static.

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    Default Re: Rectangle keeps getting faster

    The formula for speed = distance / time
    The speed will increase if the distance goes up and/or the time goes down
    Which of those two values are changing?

    showed the levels going faster and faster until it went static.
    I have no idea what that means. Do you mean the x values increased until "What is static"? The x value stopped changing.
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: Rectangle keeps getting faster

    Well, we can't really help you if you don't show us any code pertaining to how you are moving the shape about

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    Default Re: Rectangle keeps getting faster

    That is the code. That is the only code that manipulates the position.

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    Default Re: Rectangle keeps getting faster

    If the distance between positions changes at a constant rate,
    Then what about the time between moves?

    See the formula in post#6
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: Rectangle keeps getting faster

    http://pastebin.com/7sTfXa0Y
    That's my entire class code, nothing that regards to it is outside of that class. Disregard everything that doesn't involve the obstacle please!

  11. #11
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    Default Re: Rectangle keeps getting faster

    Please post the print out for the values of obstacleX.

    You skipped this question:
    What about the time between moves? Does the time decrease?
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: Rectangle keeps getting faster

    I don't have it doing that directly, I have it so every 10 times ObstacleX reaches 600, Level goes up, which is in the F3 menu.

    --- Update ---

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    --- Update ---

    There, thats the printout.

  13. #13
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    Default Re: Rectangle keeps getting faster

    Ok. Why does the code subtract 0.1 when the change is always 1?

    Now what about the times when the changes are made?

    For example if a shape's position is changed by 10 units every 10 seconds
    and then it is changed to changing every 5 seconds, the speed of the shape will double.

    How often are the changes in the rectangles position made? The System class has a method that returns the current time in milliseconds that could be used to determine when the changes in the x location are made.
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: Rectangle keeps getting faster

    I tried substituting, it doesn't matter. I don't know what you're talking about. I need a fix.... Sorry if I'm being hard to deal with.

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    Default Re: Rectangle keeps getting faster

    It's a problem when converting between doubles and ints. You are losing precision when you subtract 0.1 then convert the result to an int. If my memory is correct, I believe when Java converts to an int it simply truncates the decimal places. So the result of 2 - 0.1 would be 1.

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    Default Re: Rectangle keeps getting faster

    Did you look at times when the changes in obstacleX happens? Is it change more frequently to make it move faster?

    For testing change the width/distance the shape moves to 100 from 600 so the print out doesn't take so many lines.
    Print out the value of System.currentTimeMillis() with the changes of obstacleX.

    I need a fix...
    If you want help with the code, make a small, complete program that compiles, executes and shows the problem and paste it here.
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: Rectangle keeps getting faster

    The problem is: It goes slow at first then starts to go hyperspeed. Thats it. I dont know how else to say it.

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    Default Re: Rectangle keeps getting faster

    If the code changes the position of the shape too often, the speed will be high.
    How often does the position change?
    For example if in the beginning the position was changed every 1 second and then as the code executed that was changed to once every 1/2 second the "speed" of movement would double. Then if the position would be changed every 1/4 of a second the speed would double again. And so on.
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: Rectangle keeps getting faster

    You might not need to call the repaint() method at the end. That may be rendering the scene a second time when it is called.

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