I'm setting up an environment where I can look at my scene through either 1 or 4 veiwports and even thou I almost got it working traversing hurdles like flickering and clipping I still got two problems left.

First my perspectives are messed up when in 4 viewport mode, they look "squashed" and wrong and I tried to fix it with :

gluPerspective(45.0f, (w/2) / (h/2), 0.1f, 100.0f);

but it's still not working.


Secondly when in 4 viewport mode I want 3 views to be fixed, like top-down, left and front but I'm having some trouble.

I thought this would give me top-down view gluLookAt(0,30,0,0,0,0,0,1,0); but it aint.


Here is my code:

void display(int what){	if(what==5){glViewport(0, 0, w, h);	glMatrixMode(GL_MODELVIEW);	glLoadIdentity();	ca.lookAt();}	if(what==1){glViewport(0, 0, w/2, h/2);	glMatrixMode(GL_MODELVIEW);	glLoadIdentity();	gluLookAt(55,15,-5,0,5,-5,0,1,0);}	if(what==2){glViewport(w/2, h/2, w, h);	glMatrixMode(GL_MODELVIEW);	glLoadIdentity();	gluLookAt(0,30,0,0,0,0,0,1,0);}	if(what==3){glViewport(w/2, 0, w, h/2);	glMatrixMode(GL_MODELVIEW);	glLoadIdentity();	ca.lookAt();}	if(what==4){glViewport(0, h/2, w/2, h);	glMatrixMode(GL_MODELVIEW);	glLoadIdentity();	gluLookAt(15,15,15,0,0,0,0,1,0);}			//glMatrixMode(GL_MODELVIEW);	//glLoadIdentity();	////gluLookAt(cos(shared.time) * shared.distance, 10, sin(shared.time) * shared.distance, 0, 0, 0, 0, 1, 0);   // Roterar kameran kring origo genom att skapa en ny vymatris varje bildruta	////ca.orbitYaw(0.05);	//ca.lookAt();	glClearColor(0, 0, 0, 1);	glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);	drawScene();	glutSwapBuffers();}void viewport(){glEnable(GL_SCISSOR_TEST);	if(!divided_view_port)	{	glViewport(0, 0, w, h);	glScissor(0,0,640,480);	glMatrixMode(GL_PROJECTION);	glLoadIdentity();	gluPerspective(45.0f, w / h, 0.1f, 100.0f);	display(5);	}else{	////////////////////// bottom left - working	glViewport(0, 0, w/2, h/2);	glScissor(0,0,w/2,h/2);	glMatrixMode(GL_PROJECTION);	glLoadIdentity();	gluPerspective(45.0f, (w/2) / (h/2), 0.1f, 100.0f);	display(1);	//////////////////////	////////////////////// top right - working	glViewport(w/2, h/2, w, h);	glScissor(w/2,h/2,w,h);	glMatrixMode(GL_PROJECTION);	glLoadIdentity();	gluPerspective(45.0f, (w/2) / (h/2), 0.1f, 100.0f);	display(2);	//////////////////////	////////////////////// bottom right -working	glViewport(w/2, 0, w, h/2);	glScissor(w/2,0,w,h/2);	glMatrixMode(GL_PROJECTION);	glLoadIdentity();	gluPerspective(45.0f, (w/2) / (h/2), 0.1f, 100.0f);	display(3);	////////////////////////	////////////////////////// top left	glViewport(0, h/2, w/2, h);	glScissor(0,h/2,w/2,h);	glMatrixMode(GL_PROJECTION);	glLoadIdentity();	gluPerspective(45.0f, (w/2) / (h/2), 0.1f, 100.0f);	display(4);	///////////////////////////}glDisable(GL_SCISSOR_TEST);glMatrixMode(GL_MODELVIEW);}

I actually managed to get everything to work after some fiddling, realised that the second pair of parameters for glViewport() was width and height not endpoints.

What I'm creating is similar to and editor but basically just training so at the moment Ortho isnt needed for what I'm doing.

Got one second question thou.

In 3 of the viewports I want to show camera position and target position and I've done so by rendering spheres at each location but I dont want these to be shown in the "perspective" viewport and I'm wondering if there is any way to do this viewport specific object culling.

One way I guess would be to render the view from the three viewports to texture, then render perspective viewport to texture, mix and render to screen but that seems like an awful lot of work for something so relatively easy.

Not sure I'm following what you mean.



At the end I got this piece which draws everything.

glClearColor(0, 0, 0, 1);	glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);	drawScene();	drawCamera();	glutSwapBuffers();

If you suggest I should do it like this instead It only produces a black screen:

if(what==5){	glMatrixMode(GL_MODELVIEW);	glLoadIdentity();        drawScene();	drawCamera();	camControll();}

If i use swapbuffers duplicate times it will start to flicker.

Or should It be like this and jsut put drawScene/drawCamera in under correct viewport?

if(what==5){         glClearColor(0, 0, 0, 1);	glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);	glMatrixMode(GL_MODELVIEW);	glLoadIdentity();        drawScene();	drawCamera();	camControll();}

Or am I going in the entierly wrong direction?

Here is the code for display(int what).

void display(int what){	if(what==5){	glMatrixMode(GL_MODELVIEW);	glLoadIdentity();	camControll();}	if(what==1){	glMatrixMode(GL_MODELVIEW);	glLoadIdentity();	gluLookAt(75,15,-5,0,5,-5,0,1,0);}	if(what==2){	glMatrixMode(GL_MODELVIEW);	glLoadIdentity();	gluLookAt(0,110,0,0,0,0,1,0,0);}	if(what==3){	glMatrixMode(GL_PROJECTION);	glLoadIdentity();	gluPerspective(45.0f, float(320) / float(240), 0.1f, 100.0f); 	glMatrixMode(GL_MODELVIEW);	glLoadIdentity();	camControll();}	if(what==4){	glMatrixMode(GL_MODELVIEW);	glLoadIdentity();	gluLookAt(185,75,25,0,28,0,0,1,0);}			glClearColor(0, 0, 0, 1);	glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);	drawScene();	drawCamera();	glutSwapBuffers();}

Ok, I'll start using those tags instead.

I'll try out what you are suggesting but I'm using perspective instead of ortho but it shouldn't be to hard to switch.

Big thanks for all the help so far.