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# Strange results with orthographic rendering

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Hello, I'm using OpenGL to project a 3d scene onto a plane, orthographically. I'm getting some strange results, my XY projection works perfectly but my XZ projection does not work at all; and my YZ projection has very strange results. I know that the problem is not in my drawing code because I manually project some points and they come out well. So I must be setting up my modelview matrix incorrectly, my only thought on it was that maybe things behind the 'camera' were not being rendered, so I tried rendering twice once facing in each direction (this didn't seem to help). Here is how I set things up: (Note that my viewing plane is defined by 'pp', which contains a point A and two vectors, E and V, and pp.normal() returns V x E)
	v3 pn	= pp.normal();	// Plane Normal

v3 auab	= pp.A + pn;	// A + unit_vector(normal)

//...

glViewport(x0,ly,isx,isy);
glMatrixMode(GL_PROJECTION);
gluOrtho2D(0,xs,0,ys);	// Cartesian

glMatrixMode(GL_MODELVIEW);
glDisable(GL_DEPTH_TEST);

glTranslatef(vd.x/2,vd.y/2,0.0f);
glTranslatef(-cc.x,-cc.y,0.0f);
glColor3f(0.0f,1.0f,0.0f);

gluLookAt(pp.A.x,		// Eye X

pp.A.y,		// Eye Y

pp.A.z,		// Eye Z

auab.x,		// Object X

auab.y,		// Object Y

auab.z,		// Object Z

0.0f,			// Up X

1.0f,			// Up Y

0.0f			// Up Z

);
// Draw


All help is appreciated, Thanks, ~SPH NOTE: I have just realized that my XZ projection doesn't work because the viewing vector is perpendicular to the up vector... *DOH* : But this still doesn't explain my strange results with my YZ projection... [edited by - ShmeeBegek on May 27, 2004 8:52:23 PM]

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Hey, I solved my own problem: I didn''t have the correct up vector for each of the views (0,1,0 just happened to be correct for XY).

Sorry about that, I''ll leave the post up for anyone else who might run into the same silly problem.

Thanks, ~SPH

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