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jon723

Orthographic projection not working when trying to render background

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I'm tryin to render my scene in such a way that I render the background to the entire screen in 2d then switch to 3d for the other objects. When I try to switch to an orthographic projection to render the background nothing is rendered but the 3d objects are rendered. Can someone point out whats wrong or tell me the correct steps to accomplish what I'm looking for.
{
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
	gluLookAt(0.0, 0.0, -10.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);

	glDisable(GL_LIGHTING);	

	/*************************************
	Draw the background
	**************************************/
	glMatrixMode(GL_PROJECTION);
	glPushMatrix();
	glLoadIdentity();
	gluOrtho2D(0,640,0,480);
	glMatrixMode(GL_MODELVIEW);
	glPushMatrix();
	glLoadIdentity();
	
	glEnable(GL_TEXTURE_2D);
	glBindTexture(GL_TEXTURE_2D, testpic);
	glTranslatef(0.0,0.0,0.0);
	glBegin(GL_TRIANGLE_FAN);
	glColor4f(1.0,1.0,1.0,1.0);
	glTexCoord2f(0.0, 0.0);	glVertex2i(-1,1);
	glTexCoord2f(1.0, 0.0);	glVertex2i(-1,-1);
	glTexCoord2f(1.0, 1.0);	glVertex2i(1,-1);
	glTexCoord2f(0.0, 1.0); glVertex2i(1,1);
	glEnd();
	glDisable(GL_TEXTURE_2D);

	glMatrixMode(GL_PROJECTION);
	glPopMatrix();
	glMatrixMode(GL_MODELVIEW);	
	glPopMatrix();

	glEnable(GL_POLYGON_OFFSET_FILL);
	glPolygonOffset(1.0,0.001);

	glEnable(GL_FOG);
	glClearColor(fogcolor[0],fogcolor[1],fogcolor[2],fogcolor[3]);

	glEnable(GL_BLEND);
	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

	glPushMatrix();
	glRotatef(-angle[1], 1.0, 1.0, 0.0);
	ptl1->Draw(t);
	glPopMatrix();	

	glPushMatrix();
	glRotatef(-angle[0], 1.0, 1.0, 0.0);
	ptl2->Draw(t);
	glPopMatrix();

	glPushMatrix();
	glRotatef(-angle[0], 1.0, 1.0, 0.0);
	ptl3->Draw(t);
	glPopMatrix();
	
	glDisable(GL_BLEND);
	glDisable(GL_POLYGON_OFFSET_FILL);
	glDisable(GL_FOG);
	

	angle[0] += tFTime;
	angle[1] += 1.5 * tFTime;
        angle[2] += 1.4 * tFTime;	

	if(angle[0] > 360.0)
		angle[0] = 1.0;
	if(angle[1] > 360.0)
		angle[1] = 1.0;	
	if(angle[3] > 360.0)
		angle[3] = 1.0;	
	
	return 1;
}

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You set the coordinate system to range from (0, 0) to (640, 480), and draw the background from (-1, 1) to (1, 1). Take a look in the lower left corner and you should see one pixel being drawn in the corner. That's your background. Assuming it got a visible color that is.

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