1. #include <GL/glut.h>
2. #include <stdlib.h>
3.  
4. GLfloat bottomVertices[][3] = {
5.     {-0.5f, -0.5f, -0.5f},
6.     {-0.5f, 0.5f, -0.5f},
7.     {0.5f, -0.5f, -0.5f},
8.     {0.5f, 0.5f, -0.5f}
9. };
10.  
11. GLfloat topVertices[][3] = {
12.     {-0.25f, -0.25f, 0.5f},
13.     {-0.25f, 0.25f, 0.5f},
14.     {0.25f, -0.25f, 0.5f},
15.     {0.25f, 0.25f, 0.5f}
16. };
17.  
18. GLfloat colors[][3] = {
19.     {1.0f, 0.0f, 0.0f}, // red
20.     {1.0f, 1.0f, 0.0f}, // yellow
21.     {0.0f, 1.0f, 0.0f}, // green
22.     {0.0f, 1.0f, 1.0f}, // cyan
23.     {0.0f, 0.0f, 1.0f}, // blue
24.     {1.0f, 0.0f, 1.0f}  // magenta
25. };
26.  
27. void drawFrustum()
28. {
29.     glPushMatrix();
30.     glTranslatef(0.0f, 0.0f, -5.0f);
31.  
32.     glBegin(GL_QUADS);
33.  
34.     // Draw bottom face in red
35.     glColor3fv(colors[0]);
36.     glVertex3fv(bottomVertices[0]);
37.     glVertex3fv(bottomVertices[1]);
38.     glVertex3fv(bottomVertices[3]);
39.     glVertex3fv(bottomVertices[2]);
40.  
41.     // Draw top face in yellow
42.     glColor3fv(colors[1]);
43.     glVertex3fv(topVertices[0]);
44.     glVertex3fv(topVertices[1]);
45.     glVertex3fv(topVertices[3]);
46.     glVertex3fv(topVertices[2]);
47.  
48.     // Draw left face in green
49.     glColor3fv(colors[2]);
50.     glVertex3fv(bottomVertices[0]);
51.     glVertex3fv(bottomVertices[1]);
52.     glVertex3fv(topVertices[1]);
53.     glVertex3fv(topVertices[0]);
54.  
55.     // Draw right face in cyan
56.     glColor3fv(colors[3]);
57.     glVertex3fv(bottomVertices[2]);
58.     glVertex3fv(bottomVertices[3]);
59.     glVertex3fv(topVertices[3]);
60.     glVertex3fv(topVertices[2]);
61.  
62.     // Draw back face in blue
63.     glColor3fv(colors[4]);
64.     glVertex3fv(bottomVertices[0]);
65.     glVertex3fv(bottomVertices[2]);
66.     glVertex3fv(topVertices[2]);
67.     glVertex3fv(topVertices[0]);
68.  
69.     // Draw front face in magenta
70.     glColor3fv(colors[5]);
71.     glVertex3fv(topVertices[3]);
72.     glVertex3fv(bottomVertices[3]);
73.     glVertex3fv(bottomVertices[1]);
74.     glVertex3fv(topVertices[1]);
75.  
76.     glEnd();
77.  
78.     glPopMatrix();
79. }
80.  
81. void display()
82. {
83.     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
84.  
85. glMatrixMode(GL_MODELVIEW);
86. glLoadIdentity();
87. drawFrustum();
88. glutSwapBuffers();
89. }
90.  
91. void reshape(int w, int h)
92. {
93. glViewport(0, 0, w, h);
94. glMatrixMode(GL_PROJECTION);
95. glLoadIdentity();
96. gluPerspective(60.0, (GLfloat)w/(GLfloat)h, 1.0, 20.0);
97. }
98.  
99. int main(int argc, char **argv)
100. {
101. glutInit(&argc, argv);
102. glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
103. glutInitWindowSize(500, 500);
104. glutCreateWindow("Frustum");
105. glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
106.  
107. glutDisplayFunc(display);
108. glutReshapeFunc(reshape);
109.  
110. glutMainLoop();
111. return 0;
112. }
113.