Clicking an Object in OpenGL.

This is a discussion on Clicking an Object in OpenGL. within the Game Programming forums, part of the General Programming Boards category; In my program i want to be able to make an object (like a plane made with a GL_QUAD) clickable. ...

  1. #1
    Registered User gpr1me's Avatar
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    Clicking an Object in OpenGL.

    In my program i want to be able to make an object (like a plane made with a GL_QUAD) clickable.

    So if i have a plane displayed on the screen i want to be able to click on a point on the screen and get the X, Y position on the plane (not the screen). Is this some sort of collision detection or something?

  2. #2
    Crazy Fool Perspective's Avatar
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    This is called "Picking". Im sure google has lots to say about it, also, NeHe has a tutorial on it.

  3. #3
    Computer guy
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    You can define 2 variables: mouseX and mouseY and set them equal to the mouse's position.
    Code:
    case WM_MOUSEMOVE:							
    {
         mouseX = LOWORD(lParam);	
         mouseY = HIWORD(lParam);	
         return 0;					
    }
    just do some calculation to figure out the X,Y on the plane.
    Hello, testing testing. Everthing is running perfectly...for now

  4. #4
    GA ichijoji's Avatar
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    Edit:

    I just read your post again and what I said to do was completely wrong. Nevermind.
    Illusion and reality become impartiality and confidence.

  5. #5
    Call me AirBronto
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    Yes it is called Picking and can be done by shooting a ray down the position of the mouse and testing to see if it is intercecting with a plane of test, if this is some sort of first person view just use the cameras look vector for your ray.

  6. #6
    vae victus! skorman00's Avatar
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    Yes it is called Picking and can be done by shooting a ray down the position of the mouse and testing to see if it is intercecting with a plane
    don't forget to transform that ray with your projection matrix.

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