1/*
2 * Copyright (c) 1991, 1992, 1993 Silicon Graphics, Inc.
3 *
4 * Permission to use, copy, modify, distribute, and sell this software and
5 * its documentation for any purpose is hereby granted without fee, provided
6 * that (i) the above copyright notices and this permission notice appear in
7 * all copies of the software and related documentation, and (ii) the name of
8 * Silicon Graphics may not be used in any advertising or
9 * publicity relating to the software without the specific, prior written
10 * permission of Silicon Graphics.
11 *
12 * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF
13 * ANY KIND,
14 * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
15 * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
16 *
17 * IN NO EVENT SHALL SILICON GRAPHICS BE LIABLE FOR
18 * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
19 * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
20 * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
21 * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
22 * OF THIS SOFTWARE.
23 */
24
25#include <stdio.h>
26#include <string.h>
27#include <stdlib.h>
28#include "glut_wrap.h"
29
30
31#define CI_OFFSET_1 16
32#define CI_OFFSET_2 32
33
34
35GLenum doubleBuffer;
36
37static void Init(void)
38{
39   fprintf(stderr, "GL_RENDERER   = %s\n", (char *) glGetString(GL_RENDERER));
40   fprintf(stderr, "GL_VERSION    = %s\n", (char *) glGetString(GL_VERSION));
41   fprintf(stderr, "GL_VENDOR     = %s\n", (char *) glGetString(GL_VENDOR));
42   fflush(stderr);
43
44}
45
46static void Reshape(int width, int height)
47{
48
49    glViewport(0, 0, (GLint)width, (GLint)height);
50
51    glMatrixMode(GL_PROJECTION);
52    glLoadIdentity();
53    glOrtho(-1.0, 1.0, -1.0, 1.0, 1, -1);
54    glMatrixMode(GL_MODELVIEW);
55}
56
57static void Key(unsigned char key, int x, int y)
58{
59
60    switch (key) {
61      case 27:
62	exit(1);
63      default:
64	break;
65    }
66
67    glutPostRedisplay();
68}
69
70static void Draw(void)
71{
72   float z = 1.0;
73
74   glClearColor(0.0, 0.0, 1.0, 0.0);
75   glClearDepth(1.0);
76   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
77   glDepthFunc(GL_EQUAL);
78   glEnable(GL_DEPTH_TEST);
79
80   glBegin(GL_TRIANGLES);
81   glColor3f(0,0,.7);
82   glVertex3f( 0.9, -0.9, z);
83   glColor3f(.8,0,0);
84   glVertex3f( 0.9,  0.9, z);
85   glColor3f(0,.9,0);
86   glVertex3f(-0.9,  0.0, z);
87   glEnd();
88
89   glFlush();
90
91   {
92      GLfloat z;
93      glReadPixels(125, 125, 1, 1, GL_DEPTH_COMPONENT, GL_FLOAT, &z);
94      printf("Z at (125, 125) = %f\n", z);
95   }
96
97   if (doubleBuffer) {
98      glutSwapBuffers();
99   }
100}
101
102static GLenum Args(int argc, char **argv)
103{
104    GLint i;
105
106    doubleBuffer = GL_FALSE;
107
108    for (i = 1; i < argc; i++) {
109        if (strcmp(argv[i], "-sb") == 0) {
110	    doubleBuffer = GL_FALSE;
111	} else if (strcmp(argv[i], "-db") == 0) {
112	    doubleBuffer = GL_TRUE;
113	} else {
114	    fprintf(stderr, "%s (Bad option).\n", argv[i]);
115	    return GL_FALSE;
116	}
117    }
118    return GL_TRUE;
119}
120
121int main(int argc, char **argv)
122{
123    GLenum type;
124
125    glutInit(&argc, argv);
126
127    if (Args(argc, argv) == GL_FALSE) {
128	exit(1);
129    }
130
131    glutInitWindowPosition(100, 0); glutInitWindowSize( 250, 250);
132
133    type = GLUT_RGB | GLUT_DEPTH;
134    type |= (doubleBuffer) ? GLUT_DOUBLE : GLUT_SINGLE;
135    glutInitDisplayMode(type);
136
137    if (glutCreateWindow(*argv) == GL_FALSE) {
138	exit(1);
139    }
140
141    Init();
142
143    glutReshapeFunc(Reshape);
144    glutKeyboardFunc(Key);
145    glutDisplayFunc(Draw);
146    glutMainLoop();
147	return 0;
148}
149