How to draw a cube in OpenGL?

Question

I need help. I have found several solutions to draw cube in OpenGl, but I have a problem.

My code is:

    wglMakeCurrent(pDC->m_hDC, m_hrc);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();

glTranslatef(1.5f, 0.0f, -7.0f);  // Move right and into the screen

glBegin(GL_QUADS);                // Begin drawing the color cube with 6 quads
                                  // Top face (y = 1.0f)
                                  // Define vertices in counter-clockwise (CCW) order with normal pointing out
glColor3f(0.0f, 1.0f, 0.0f);     // Green
glVertex3f(1.0f, 1.0f, -1.0f);
glVertex3f(-1.0f, 1.0f, -1.0f);
glVertex3f(-1.0f, 1.0f, 1.0f);
glVertex3f(1.0f, 1.0f, 1.0f);

// Bottom face (y = -1.0f)
glColor3f(1.0f, 0.5f, 0.0f);     // Orange
glVertex3f(1.0f, -1.0f, 1.0f);
glVertex3f(-1.0f, -1.0f, 1.0f);
glVertex3f(-1.0f, -1.0f, -1.0f);
glVertex3f(1.0f, -1.0f, -1.0f);

// Front face  (z = 1.0f)
glColor3f(1.0f, 0.0f, 0.0f);     // Red
glVertex3f(1.0f, 1.0f, 1.0f);
glVertex3f(-1.0f, 1.0f, 1.0f);
glVertex3f(-1.0f, -1.0f, 1.0f);
glVertex3f(1.0f, -1.0f, 1.0f);

// Back face (z = -1.0f)
glColor3f(1.0f, 1.0f, 0.0f);     // Yellow
glVertex3f(1.0f, -1.0f, -1.0f);
glVertex3f(-1.0f, -1.0f, -1.0f);
glVertex3f(-1.0f, 1.0f, -1.0f);
glVertex3f(1.0f, 1.0f, -1.0f);

// Left face (x = -1.0f)
glColor3f(0.0f, 0.0f, 1.0f);     // Blue
glVertex3f(-1.0f, 1.0f, 1.0f);
glVertex3f(-1.0f, 1.0f, -1.0f);
glVertex3f(-1.0f, -1.0f, -1.0f);
glVertex3f(-1.0f, -1.0f, 1.0f);

// Right face (x = 1.0f)
glColor3f(1.0f, 0.0f, 1.0f);     // Magenta
glVertex3f(1.0f, 1.0f, -1.0f);
glVertex3f(1.0f, 1.0f, 1.0f);
glVertex3f(1.0f, -1.0f, 1.0f);
glVertex3f(1.0f, -1.0f, -1.0f);
glEnd();  // End of drawing color-cube

glFlush();                  

SwapBuffers(pDC->m_hDC);
wglMakeCurrent(NULL, NULL);

Bellow is the image I want to get and the image I get. expected image and the image I get

How to solve this problem?

Solution

You'll have to enable depth testing. Otherwise triangles are drawn in the order the are given in code which leads to overdraws even if a triangle is behind another one. To enable depth-testing call

glEnable(GL_DEPTH_TEST);

before issuing the first draw-call.