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Xna

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  • 13-09-2013 11:18am
    #1
    Drexel
    Registered Users Posts: 3,500 ✭✭✭


    Hey I have a bit of a maths question that I need help with. Any help'd be great.

    Just messing around in Xna and messing with sprites and stuff/

    I have a square (a 48 * 48 image) which I can track on screen by the x and y of the top left point of the square. This is all fine. I want to be able to rotate the square and still keep track of the same point. for instance if I rotate 90degrees clockwise and the orginal X position was 200 the new X position should be 200 + 48(the size of the width of the image). Its fine for 90 degrees I am able to work that out in my head but each one in between is the problem! I know there is prob some kind of formula to work this out. Any help would be great! Oh the square is rotating on its center


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    #2
    Encrypted Pigeon
    Registered Users Posts: 12,754 ✭✭✭✭Encrypted Pigeon


    If the square is rotating about the center as it is, why not do your calculations based on the center of the sprite?

    Anyway this (http://gamedev.stackexchange.com/a/18341 is one way of doing it, you know the radius and center of the sprite and angle you are rotating about the origin so simple trigonometry.

    Edit: fix link


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    #3
    Drexel
    Registered Users Posts: 3,500 ✭✭✭Drexel


    CoderDozer wrote: »
    If the square is rotating about the center as it is, why not do your calculations based on the center of the sprite?

    Anyway this (http://gamedev.stackexchange.com/a/18341 is one way of doing it, you know the radius and center of the sprite and angle you are rotating about the origin so simple trigonometry.

    Edit: fix link

    Nice one. Thats exactly what I was looking for. I knew there was some way to work it out but wasnt sure what to google! Now to remember it all!!


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