src/trivial/quad-tex-sub.c

   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 <glad/glad.h>
  29 #include "glut_wrap.h"
  30
  31
  32 #define CI_OFFSET_1 16
  33 #define CI_OFFSET_2 32
  34
  35 #define SIZE 16
  36 GLenum doubleBuffer;
  37 GLint line = 0;
  38
  39 static void MakeImage(void)
  40 {
  41    GLubyte tex2d[SIZE][SIZE][3];
  42    GLint s, t;
  43
  44    for (s = 0; s < SIZE; s++) {
  45       for (t = 0; t < SIZE; t++) {
  46          tex2d[t][s][0] = s*255/(SIZE-1);
  47          tex2d[t][s][1] = t*255/(SIZE-1);
  48          tex2d[t][s][2] = 0*255/(SIZE-1);
  49       }
  50    }
  51
  52    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
  53    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB,
  54                 SIZE, SIZE,
  55                 0,
  56                 GL_RGB, GL_UNSIGNED_BYTE, tex2d);
  57    glPixelStorei(GL_UNPACK_ALIGNMENT, 4);
  58    glEnable(GL_TEXTURE_2D);
  59 }
  60
  61 static void UpdateLine(void)
  62 {
  63    GLubyte tex[SIZE][3];
  64    GLubyte b = 0;
  65    GLint s, t;
  66
  67    t = line % SIZE;
  68    if (line % (SIZE * 2) < SIZE)
  69       b = 255;
  70    else
  71       b = 0;
  72
  73    for (s = 0; s < SIZE; s++) {
  74       tex[s][0] = s*255/(SIZE-1);
  75       tex[s][1] = t*255/(SIZE-1);
  76       tex[s][2] = b;
  77    }
  78
  79    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
  80    glTexSubImage2D(GL_TEXTURE_2D, 0,
  81                    0, t,
  82                    SIZE, 1,
  83                    GL_RGB, GL_UNSIGNED_BYTE, tex);
  84    glPixelStorei(GL_UNPACK_ALIGNMENT, 4);
  85 }
  86
  87 static void Init(void)
  88 {
  89    fprintf(stderr, "GL_RENDERER   = %s\n", (char *) glGetString(GL_RENDERER));
  90    fprintf(stderr, "GL_VERSION    = %s\n", (char *) glGetString(GL_VERSION));
  91    fprintf(stderr, "GL_VENDOR     = %s\n", (char *) glGetString(GL_VENDOR));
  92    fflush(stderr);
  93
  94    glClearColor(0.0, 0.0, 1.0, 0.0);
  95
  96    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
  97    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
  98    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
  99    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 100    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 101
 102    MakeImage();
 103    UpdateLine();
 104    line++;
 105 }
 106
 107 static void Reshape(int width, int height)
 108 {
 109
 110     glViewport(0, 0, (GLint)width, (GLint)height);
 111
 112     glMatrixMode(GL_PROJECTION);
 113     glLoadIdentity();
 114     glOrtho(-1.0, 1.0, -1.0, 1.0, -0.5, 1000.0);
 115     glMatrixMode(GL_MODELVIEW);
 116 }
 117
 118 static void Key(unsigned char key, int x, int y)
 119 {
 120
 121    switch (key) {
 122    case 27:
 123       exit(1);
 124    default:
 125       UpdateLine();
 126       line++;
 127       break;
 128    }
 129
 130    glutPostRedisplay();
 131 }
 132
 133 static void Draw(void)
 134 {
 135    glClear(GL_COLOR_BUFFER_BIT);
 136
 137    glBegin(GL_QUADS);
 138    glTexCoord2f(1,0);
 139    glVertex3f( 0.9, -0.9, -30.0);
 140    glTexCoord2f(1,1);
 141    glVertex3f( 0.9,  0.9, -30.0);
 142    glTexCoord2f(0,1);
 143    glVertex3f(-0.9,  0.9, -30.0);
 144    glTexCoord2f(0,0);
 145    glVertex3f(-0.9,  -0.9, -30.0);
 146    glEnd();
 147
 148    glFlush();
 149
 150    if (doubleBuffer) {
 151       glutSwapBuffers();
 152    }
 153 }
 154
 155 static GLenum Args(int argc, char **argv)
 156 {
 157    GLint i;
 158
 159    doubleBuffer = GL_FALSE;
 160
 161    for (i = 1; i < argc; i++) {
 162       if (strcmp(argv[i], "-sb") == 0) {
 163          doubleBuffer = GL_FALSE;
 164       } else if (strcmp(argv[i], "-db") == 0) {
 165          doubleBuffer = GL_TRUE;
 166       } else {
 167          fprintf(stderr, "%s (Bad option).\n", argv[i]);
 168          return GL_FALSE;
 169       }
 170    }
 171    return GL_TRUE;
 172 }
 173
 174 int main(int argc, char **argv)
 175 {
 176    GLenum type;
 177
 178    glutInit(&argc, argv);
 179
 180    if (Args(argc, argv) == GL_FALSE) {
 181       exit(1);
 182    }
 183
 184    glutInitWindowPosition(0, 0);
 185    glutInitWindowSize(250, 250);
 186
 187    type = GLUT_RGB | GLUT_ALPHA;
 188    type |= (doubleBuffer) ? GLUT_DOUBLE : GLUT_SINGLE;
 189    glutInitDisplayMode(type);
 190
 191    if (glutCreateWindow(*argv) == GL_FALSE) {
 192       exit(1);
 193    }
 194
 195    gladLoadGL();
 196
 197    Init();
 198
 199    glutReshapeFunc(Reshape);
 200    glutKeyboardFunc(Key);
 201    glutDisplayFunc(Draw);
 202    glutMainLoop();
 203    return 0;
 204 }