Open GL Create 4 Views Like 3ds max or maya - c++

Question

How can I Create a 4 views (LEFT/TOP/PERSPECTIVE/FRONT) in Open GL ??
I Have Used this :
int main(int c,char ** argv)
{
glutInit(&c,argv);
glutInitDisplayMode(GLUT_DOUBLE |GLUT_DEPTH |GLUT_RGB );
glutInitWindowSize(w,h);
MainWin =glutCreateWindow("Teapot Window");
glutDisplayFunc(display);
LeftWin = glutCreateSubWindow(MainWin,0,0,s_window_w,s_window_h);
glutDisplayFunc(displayLeft);
glutReshapeFunc(reshapeLeft);
TopWin = glutCreateSubWindow(MainWin,s_window_w+3,0,s_window_w,s_window_h);
glutDisplayFunc(displayTop);
glutReshapeFunc(reshapeTop);
PerspectiveWin = glutCreateSubWindow(MainWin,0,s_window_h+3,s_window_w,s_window_h);
glutDisplayFunc(displayPerspective);
glutReshapeFunc(reshapePerspective);
FrontWin = glutCreateSubWindow(MainWin,s_window_w+3,s_window_h+3,s_window_w,s_window_h);
glutDisplayFunc(displayFront);
glutReshapeFunc(reshapeFront);
glutMainLoop();
return 0;
}
Then I have make the projection for top and left and like this :
glViewport(0,0,w,h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(-0.5f,0.5f,-0.35f,0.35f,1,500);
When I use the top lines for the front also , the output is something like this :
Where is my fault ?
thanks in advance
Why the Front view is empty and the perspective and left view are same ??
For perspective projection i had used glFrustum ....
So Am I going wrong ?
Please help on creating multiple views like 3ds max or maya ...
below is the code for display functions:
void displayLeft()
{
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
gluLookAt(0,0,-1,0,0,0,0,1,0);
glEnable(GL_DEPTH_TEST);
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
glLightfv(GL_LIGHT0,GL_POSITION,light_pos);
glShadeModel(GL_SMOOTH);
glClearColor(0.2f,0.3f,0.4f,1);
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
glPushMatrix();
glEnable(GL_COLOR_MATERIAL);
glTranslatef(teapot_x,teapot_y,teapot_z);
glRotatef(teapot_angle,0,1,0);
glColor3f(0,1,0);
glutSolidTeapot(0.2f);
glPopMatrix();
glFlush();
glutSwapBuffers();
}
void displayTop()
{
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
gluLookAt(0,-1,0,0,0,0,0,0,-1);
glEnable(GL_DEPTH_TEST);
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
glLightfv(GL_LIGHT0,GL_POSITION,light_pos);
glShadeModel(GL_SMOOTH);
glClearColor(0.2f,0.3f,0.4f,1);
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
glPushMatrix();
glEnable(GL_COLOR_MATERIAL);
glTranslatef(teapot_x,teapot_y,teapot_z);
glRotatef(teapot_angle,0,1,0);
glColor3f(0,1,0);
glutSolidTeapot(0.2f);
glPopMatrix();
glFlush();
glutSwapBuffers();
}
void displayFront()
{
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
gluLookAt(0,0,0,0,0,0,1,0,0);
glEnable(GL_DEPTH_TEST);
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
glLightfv(GL_LIGHT0,GL_POSITION,light_pos);
glShadeModel(GL_SMOOTH);
glClearColor(0.2f,0.3f,0.4f,1);
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
glPushMatrix();
glEnable(GL_COLOR_MATERIAL);
glTranslatef(teapot_x,teapot_y,teapot_z);
glRotatef(teapot_angle,0,1,0);
glColor3f(0,1,0);
glutSolidTeapot(0.2f);
glPopMatrix();
glFlush();
glutSwapBuffers();
}
void displayPerspective()
{
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
gluLookAt(0,0,-1,0,0,0,0,1,0);
glEnable(GL_DEPTH_TEST);
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
glLightfv(GL_LIGHT0,GL_POSITION,light_pos);
glShadeModel(GL_SMOOTH);
glClearColor(0.2f,0.3f,0.4f,1);
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
glPushMatrix();
glEnable(GL_COLOR_MATERIAL);
glTranslatef(teapot_x,teapot_y,teapot_z);
glRotatef(0,0,1,0);
glColor3f(0,1,0);
glutSolidTeapot(0.2f);
glPopMatrix();
glFlush();
glutSwapBuffers();
}

Answer 1

Use glViewport and glScissor to cut out panes of the window. Then for each pane perform the rendering as usual. Setting the projection matrix is actually a drawing state operation, so it belongs into the display function, not reshape.
Your display function should become something like
void ViewportScissor(int x, int y, int width, int height)
{
glViewport(x, y, width, height);
glScissor(x, y, width, height);
}
void display(void)
{
int const win_width = glutGet(GLUT_WINDOW_WIDTH);
int const win_height = glutGet(GLUT_WINDOW_HEIGHT);
glDisable(GL_SCISSOR);
glClear(…);
glEnable(GL_SCISSOR);
ViewportScissor(0, 0, win_width/2, win_height/2);
glMatrixMode(GL_PROJECTION);
setup_frontview_projection();
glMatrixMode(GL_MODELVIEW);
setup_frontview();
draw_scene();
ViewportScissor(win_width/2, 0, win_width/2, win_height/2);
glMatrixMode(GL_PROJECTION);
setup_rightview_projection();
glMatrixMode(GL_MODELVIEW);
setup_rightview();
draw_scene();
ViewportScissor(0, win_height/2, win_width/2, win_height/2);
glMatrixMode(GL_PROJECTION);
setup_topview_projection();
glMatrixMode(GL_MODELVIEW);
setup_topview();
draw_scene();
ViewportScissor(win_width/2, win_height/2, win_width/2, win_height/2);
glMatrixMode(GL_PROJECTION);
setup_freecamview_projection();
glMatrixMode(GL_MODELVIEW);
setup_freecamview();
draw_scene();
glutSwapBuffers();
}
Adding splitter lines/frames is left as an exercise for the reader.