i'm trying to convert a function for getting 3d world coords in opengl from the mouse position using opengl and c#. the function below in c/c++ works fine (aside from the array variables at the top which i changed to c#. however the rest of the function, primarily glReadPixels and gluUnProject give compiler errors.

CVector mouse2dto3d()
{
    unsafe
    {
        int[] viewport = new int[4];
        double[] modelview = new double[16];
        double[] projection = new double[16];
        float  wz;
        double x;
        double y;
        double z;

        Gl.glGetIntegerv(Gl.GL_VIEWPORT, viewport);
        Gl.glGetDoublev(Gl.GL_MODELVIEW_MATRIX, modelview);
        Gl.glGetDoublev(Gl.GL_PROJECTION_MATRIX, projection);
        Gl.glReadPixels(mouse_x, viewport[3] - mouse_x, 1, 1, Gl.GL_DEPTH_COMPONENT, Gl.GL_FLOAT, &wz);
        Glu.gluUnProject((double)mouse_y, (double)viewport[3] - (double)mouse_y, (double)wz, modelview, projection, viewport, (double)x, (double)y, (double)z);

        CVector temp = new CVector((float)x, (float)y, (float)z);

        return temp;
    }
}

Errors: Error 1 The best overloaded method match for 'Tao.OpenGl.Gl.glReadPixels(int, int, int, int, int, int, object)' has some invalid arguments Error 2 Argument '7': cannot convert from 'float*' to 'object' Error 3 The best overloaded method match for 'Tao.OpenGl.Glu.gluUnProject(double, double, double, double[], double[], int[], out double, out double, out double)' has some invalid arguments Error 4 Argument '7' must be passed with the 'out' keyword Error 5 Argument '8' must be passed with the 'out' keyword Error 6 Argument '9' must be passed with the 'out' keyword Thanks! Scott

glReadPixels has two overloads: IntPtr and object. Try this:

I'm trying:

Gl.glReadPixels((double)last_mouseX, (double)viewport[3] - (double)last_mouseY, 1, 1, Gl.GL_DEPTH_COMPONENT, Gl.GL_FLOAT, (IntPtr)&wz);

but it results in the error:

Error 1 'System.IntPtr' is a 'type' but is used like a 'variable'

thanks for the reply,
Scott

aw i'm dumb. got it.

i forgot to make wz a float array... just like you told me to do.

thanks for the help.