IELTS Practice Tests with Explanatory Key (+ Audio CD)

 else glClear(GL_COLOR_BUFFER_BIT);  /* draw the floor */  glBegin(GL_QUADS);  glColor3f(0.2f, 0.2f, 0.2f);  glVertex3f(-100.0, 0.0, –100.0);  glColor3f(0.4f, 0.4f, 0.4f);  glVertex3f(-100.0, 0.0, 100.0);  glColor3f(0.6f, 0.6f, 0.6f);  glVertex3f(100.0, 0.0, 100.0);  glColor3f(0.8f, 0.8f, 0.8f);  glVertex3f(100.0, 0.0, –100.0);  glEnd();  /* draw 12 cubes with different colors */  drawcube(75, 57, 2);  drawcube(-65, –12, 3);  drawcube(50, –50, 1);  drawcube(-56, 17, 2);  drawcube(67, 12, 3);  drawcube(-87, 32, 1);  drawcube(-26, 75, 2);  drawcube(57, 82, 3);  drawcube(-3, 12, 1);  drawcube(46, 35, 2);  drawcube(37, –2, 3);  glutSwapBuffers(); } void keyboard(unsigned char key, int x, int y) {  /* This time the controls are:   "a": move left   "d": move right   "w": move forward   "s": move back   "t": toggle depth-testing */  switch (key) {  case 'a':  case 'A':   glTranslatef(5.0, 0.0, 0.0);   break;  case 'd':  case 'D':   glTranslatef(-5.0, 0.0, 0.0);   break;  case 'w':  case 'W':   glTranslatef(0.0, 0.0, 5.0); ...»