Draw a cube and rotate it: a part of the cube disappears - c

Question

In this code I try to draw a cube.I try to draw all faces vertices anticlockwise.
The problem is that if I don't rotate the cube only the red face is drawn, if instead I rotate it of 5 degrees, I just see a part of the cube.
#import <OpenGL/OpenGL.h>
#import <GLUT/GLUT.h>
int width=500, height=500, depth=500;
void init()
{
glEnable(GL_DEPTH_TEST);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
gluLookAt(200, 200,-200, 200, 200, 0, 0, 1, 0);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluOrtho2D(0,width,0,height);
gluPerspective(90, 1, -100, 100);
glViewport(0, 0, width, height);
}
void drawCube()
{
int vertices[8][3]= { {100,100,0} , {300,100,0}, {300,300,0}, {100,300,0}, {100,100,300} , {300,100,300}, {300,300,300}, {100,300,300} };
glBegin(GL_QUADS);
glColor4f(1, 0, 0, 0);
glVertex3iv(vertices[0]);
glVertex3iv(vertices[1]);
glVertex3iv(vertices[2]);
glVertex3iv(vertices[3]);
glVertex3iv(vertices[4]);
glVertex3iv(vertices[5]);
glVertex3iv(vertices[6]);
glVertex3iv(vertices[7]);
glColor4f(0, 1, 0, 0);
glVertex3iv(vertices[1]);
glVertex3iv(vertices[5]);
glVertex3iv(vertices[6]);
glVertex3iv(vertices[4]);
glVertex3iv(vertices[0]);
glVertex3iv(vertices[4]);
glVertex3iv(vertices[7]);
glVertex3iv(vertices[3]);
glColor4f(0, 0, 1, 0);
glVertex3iv(vertices[3]);
glVertex3iv(vertices[2]);
glVertex3iv(vertices[6]);
glVertex3iv(vertices[7]);
glVertex3iv(vertices[0]);
glVertex3iv(vertices[1]);
glVertex3iv(vertices[5]);
glVertex3iv(vertices[4]);
glEnd();
}
void display()
{
glClearColor(0.0, 0.0, 0.0, 0);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glTranslatef(200,200,150);
glRotatef(5, 0, 1, 0);
glTranslatef(-200,-200,-150);
drawCube();
glutSwapBuffers();
}
void idle(void)
{
}
int main(int argc, char * argv[])
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
glutInitWindowPosition(100, 100);
glutInitWindowSize(width, height);
glutCreateWindow("Test");
glutDisplayFunc(display);
glutIdleFunc(idle);
init();
glutMainLoop();
return 0;
}
This is what I see:
But I should see a rotated cube, so I should see the part of the other face on the right.My doubt is that I'm going wrong with drawing the vertices in anticlockwise order, or something else.
PS: the code is outdated, because at my university I don't have the possibility to study the newest version of OpenGL, and I must use GLUT.

Answer 1

Couple problems:
Your projection matrix setup is not sensical.
Firstly, you should decide if you want an orthographic, or a perspective projection.
If you want orthographic, use gluOrtho2d. If you want a perspective projection, use gluPerspective. Using both will generate a bizarre transformation that's certainly not what you want.
gluPerspective can't have a negative near plane. The near plane should be greater than zero, perhaps something small like 1, with a far plane defining how far away from the camera you want the back clip plane to be. Since you seem to be using units in the hundreds, I might recommend a back plane of 1000 or so.
You're calling gluLookAt, but erasing the view matrix by calling glLoadIdentity in display(). If you want a view matrix, don't erase it after you program it.