1/*
2 * Copyright (c) 1993-1997, Silicon Graphics, Inc.
3 * ALL RIGHTS RESERVED
4 * Permission to use, copy, modify, and distribute this software for
5 * any purpose and without fee is hereby granted, provided that the above
6 * copyright notice appear in all copies and that both the copyright notice
7 * and this permission notice appear in supporting documentation, and that
8 * the name of Silicon Graphics, Inc. not be used in advertising
9 * or publicity pertaining to distribution of the software without specific,
10 * written prior permission.
11 *
12 * THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS"
13 * AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE,
14 * INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR
15 * FITNESS FOR A PARTICULAR PURPOSE.  IN NO EVENT SHALL SILICON
16 * GRAPHICS, INC.  BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT,
17 * SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY
18 * KIND, OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION,
19 * LOSS OF PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF
20 * THIRD PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC.  HAS BEEN
21 * ADVISED OF THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON
22 * ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE
23 * POSSESSION, USE OR PERFORMANCE OF THIS SOFTWARE.
24 *
25 * US Government Users Restricted Rights
26 * Use, duplication, or disclosure by the Government is subject to
27 * restrictions set forth in FAR 52.227.19(c)(2) or subparagraph
28 * (c)(1)(ii) of the Rights in Technical Data and Computer Software
29 * clause at DFARS 252.227-7013 and/or in similar or successor
30 * clauses in the FAR or the DOD or NASA FAR Supplement.
31 * Unpublished-- rights reserved under the copyright laws of the
32 * United States.  Contractor/manufacturer is Silicon Graphics,
33 * Inc., 2011 N.  Shoreline Blvd., Mountain View, CA 94039-7311.
34 *
35 * OpenGL(R) is a registered trademark of Silicon Graphics, Inc.
36 */
37
38/*  texsub.c
39 *  This program texture maps a checkerboard image onto
40 *  two rectangles.  This program clamps the texture, if
41 *  the texture coordinates fall outside 0.0 and 1.0.
42 *  If the s key is pressed, a texture subimage is used to
43 *  alter the original texture.  If the r key is pressed,
44 *  the original texture is restored.
45 */
46#include "glut_wrap.h"
47#include <stdlib.h>
48#include <stdio.h>
49
50#ifdef GL_VERSION_1_1
51/*  Create checkerboard textures  */
52#define checkImageWidth 64
53#define checkImageHeight 64
54#define subImageWidth 16
55#define subImageHeight 16
56static GLubyte checkImage[checkImageHeight][checkImageWidth][4];
57static GLubyte subImage[subImageHeight][subImageWidth][4];
58
59static GLuint texName;
60
61static void makeCheckImages(void)
62{
63   int i, j, c;
64
65   for (i = 0; i < checkImageHeight; i++) {
66      for (j = 0; j < checkImageWidth; j++) {
67         c = ((((i&0x8)==0)^((j&0x8)==0)))*255;
68         checkImage[i][j][0] = (GLubyte) c;
69         checkImage[i][j][1] = (GLubyte) c;
70         checkImage[i][j][2] = (GLubyte) c;
71         checkImage[i][j][3] = (GLubyte) 255;
72      }
73   }
74   for (i = 0; i < subImageHeight; i++) {
75      for (j = 0; j < subImageWidth; j++) {
76         c = ((((i&0x4)==0)^((j&0x4)==0)))*255;
77         subImage[i][j][0] = (GLubyte) c;
78         subImage[i][j][1] = (GLubyte) 0;
79         subImage[i][j][2] = (GLubyte) 0;
80         subImage[i][j][3] = (GLubyte) 255;
81      }
82   }
83}
84
85static void init(void)
86{
87   glClearColor (0.0, 0.0, 0.0, 0.0);
88   glShadeModel(GL_FLAT);
89   glEnable(GL_DEPTH_TEST);
90
91   makeCheckImages();
92   glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
93
94   glGenTextures(1, &texName);
95   glBindTexture(GL_TEXTURE_2D, texName);
96
97   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
98   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
99   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
100   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
101   glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, checkImageWidth, checkImageHeight,
102                0, GL_RGBA, GL_UNSIGNED_BYTE, checkImage);
103}
104
105static void display(void)
106{
107   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
108   glEnable(GL_TEXTURE_2D);
109   glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);
110   glBindTexture(GL_TEXTURE_2D, texName);
111   glBegin(GL_QUADS);
112   glTexCoord2f(0.0, 0.0); glVertex3f(-2.0, -1.0, 0.0);
113   glTexCoord2f(0.0, 1.0); glVertex3f(-2.0, 1.0, 0.0);
114   glTexCoord2f(1.0, 1.0); glVertex3f(0.0, 1.0, 0.0);
115   glTexCoord2f(1.0, 0.0); glVertex3f(0.0, -1.0, 0.0);
116
117   glTexCoord2f(0.0, 0.0); glVertex3f(1.0, -1.0, 0.0);
118   glTexCoord2f(0.0, 1.0); glVertex3f(1.0, 1.0, 0.0);
119   glTexCoord2f(1.0, 1.0); glVertex3f(2.41421, 1.0, -1.41421);
120   glTexCoord2f(1.0, 0.0); glVertex3f(2.41421, -1.0, -1.41421);
121   glEnd();
122   glFlush();
123   glDisable(GL_TEXTURE_2D);
124}
125
126static void reshape(int w, int h)
127{
128   glViewport(0, 0, (GLsizei) w, (GLsizei) h);
129   glMatrixMode(GL_PROJECTION);
130   glLoadIdentity();
131   gluPerspective(60.0, (GLfloat) w/(GLfloat) h, 1.0, 30.0);
132   glMatrixMode(GL_MODELVIEW);
133   glLoadIdentity();
134   glTranslatef(0.0, 0.0, -3.6);
135}
136
137/* ARGSUSED1 */
138static void keyboard (unsigned char key, int x, int y)
139{
140   switch (key) {
141      case 's':
142      case 'S':
143         glBindTexture(GL_TEXTURE_2D, texName);
144         glTexSubImage2D(GL_TEXTURE_2D, 0, 12, 44, subImageWidth,
145                         subImageHeight, GL_RGBA,
146                         GL_UNSIGNED_BYTE, subImage);
147         glutPostRedisplay();
148         break;
149      case 'r':
150      case 'R':
151         glBindTexture(GL_TEXTURE_2D, texName);
152         glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, checkImageWidth,
153                      checkImageHeight, 0, GL_RGBA,
154                      GL_UNSIGNED_BYTE, checkImage);
155         glutPostRedisplay();
156         break;
157      case 27:
158         exit(0);
159         break;
160      default:
161         break;
162   }
163}
164
165int main(int argc, char** argv)
166{
167   glutInit(&argc, argv);
168   glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);
169   glutInitWindowSize(250, 250);
170   glutInitWindowPosition(100, 100);
171   glutCreateWindow(argv[0]);
172   init();
173   glutDisplayFunc(display);
174   glutReshapeFunc(reshape);
175   glutKeyboardFunc(keyboard);
176   glutMainLoop();
177   return 0;
178}
179#else
180int main(int argc, char** argv)
181{
182    fprintf (stderr, "This program demonstrates a feature which is not in OpenGL Version 1.0.\n");
183    fprintf (stderr, "If your implementation of OpenGL Version 1.0 has the right extensions,\n");
184    fprintf (stderr, "you may be able to modify this program to make it run.\n");
185    return 0;
186}
187#endif
188