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Editorial Team
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Asked: 2026-05-19T02:27:25+00:00

I draw a sphere with OpenGL which will be transformed by glRotate(), glScale(), glTranslate().

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I draw a sphere with OpenGL which will be transformed by glRotate(), glScale(), glTranslate().
How could I get the absolute Position of the Object without calculating all transformations on my own?

I need the coordinates for setting the camera eye position to this point.

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1 Answer

  1. Editorial Team

    When using those transformations, you are manipulating the modelviewmatrix

    To get the current one you can use ( http://linux.die.net/man/3/glgetfloatv )

    void glGetFloatv(
GLenum pname,
GLfloat * params
);

    for example:

    float modelview[16];

// save the current modelview matrix
glPushMatrix();

// get the current modelview matrix
glGetFloatv(GL_MODELVIEW_MATRIX , modelview);

    should get you the current matrix, multiplying the starting vectors/vertices/coordinates with this matrix will give you the absolute world coordinates.

    EDIT: When making an application you usually want control over the absolute coordinates of each object, manipulate them, and use the opengl transformations to draw them where they are defined.

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