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Thread: glFrustum delete my current matrix

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  1. #1
    Newbie Newbie
    Join Date
    Sep 2013
    Posts
    2

    glFrustum delete my current matrix

    I don't know why, but I use the command glFrustum to increase the far depth of the clipping plane, but I can't see more the object i created..
    Here I post the relevant code.. I am now reading the red book, maybe I don't understand something..
    please help me..it's very important..

    Code :
    	glMatrixMode(GL_PROJECTION);
    	glLoadMatrixd( gl_para );
    	glFrustum (-100.0, 100.0, -100.0, 100.0, 1.5, 2000.0);
    	glMatrixMode(GL_PROJECTION);
     
            glRotated(180,1,0,0);
    	glutWireCone(40,40*arrow_factor,10,100);
    	glRotated(-180,1,0,0);

  2. #2
    Junior Member Newbie
    Join Date
    Aug 2013
    Posts
    19
    Hi Jack. I need more information to help you. Can you describe what you expect to see and what you actually do see? On the one hand you make it sound like your gl_para matrix is getting overwritten by a unit matrix; and on the other hand it sounds like the far clipping plane is cutting off the distant part of your object. Which is it? How many bits are you using for depth? If you change the 1.5 and 2000.0 numbers, you should be able to at least _change_ the amount of your model that gets clipped off, front and rear.

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