JOGL-glu.gluUnProject总是返回0.0 [英] JOGL - glu.gluUnProject always returning 0.0

问题描述

我目前正在尝试找出如何从JOGL获取世界坐标的方法-不管我在哪里单击，它现在仅返回x = 0.0，y = 0.0和z = 0.0.我在做什么错了?

I'm currently trying to work out how to get world coordinates from JOGL - at the moment it only returns x = 0.0, y= 0.0 and z = 0.0 no matter where I click. What am I doing wrong?

 public double[] getMousePosition(int x, int y){

    int viewport[] = new int[4];
    double modelview[] = new double[16];
    double projection[] = new double[16];
    float winX, winY, winZ;
    float posX, posY, posZ;
    double wcoord[] = new double[4];

    gl.glGetDoublev( GL2.GL_MODELVIEW_MATRIX, modelview, 0 );
    gl.glGetDoublev( GL2.GL_PROJECTION_MATRIX, projection, 0 );
    gl.glGetIntegerv( GL2.GL_VIEWPORT, viewport, 0 );

    winX = (float)x;
    winY = (float)viewport[3] - (float)y;

    float[] depth = new float[1];
    // gl.glReadPixels(winX, winY, 1, 1, gl.GL_DEPTH_COMPONENT, GL2.GL_FLOAT, depth);

    boolean test =  glu.gluUnProject( winX, winY, 0.0, modelview, 0, projection, 0, viewport, 0, wcoord, 0);

    System.out.println("x: " + wcoord[0] +"y: "+wcoord[1]+" worked? "+test);
    System.out.println(modelview[0]);
    return wcoord;
}

:忘记提及我注意到glu.gluUnproject返回一个布尔值，因此我将其分配给一个名为test的布尔值，该布尔值返回false.

EDIT :: Forgot to mention that I noticed that glu.gluUnproject returns a boolean so I assigned it to a boolean called test which returns false.

EDIT2 ::我添加了另一个调试语句-System.out.println(modelview [0]);并且还返回0.0

EDIT2 :: I've added another debug statement - System.out.println(modelview[0]); and is also returning 0.0

谢谢您的帮助

詹姆斯

推荐答案

我终于找到了发生这种情况的原因，事实证明我在拉gl.glGetIntegerv(GL2.GL_VIEWPORT，viewport，0);在此之前的一种方法中.看来，如果执行此操作，则下一个调用它的方法将只返回一组零而不会返回任何结果！

I've finally found the reason why this was happening, it turns out that I was pulling gl.glGetIntegerv( GL2.GL_VIEWPORT, viewport, 0 ); in a method before this one. It seems that if you do this the next method to call it will be returned nothing but a set of zeros!

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