progs/trivial/tri-viewport.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 <GL/glut.h>
  29
  30 GLenum doubleBuffer = 1;
  31 int win;
  32 static float tx = 0;
  33 static float ty = 0;
  34 static float tw = 0;
  35 static float th = 0;
  36 static float z = -5;
  37
  38
  39 static float win_width = 250;
  40 static float win_height = 250;
  41 static enum {
  42    ORTHO,
  43    FRUSTUM,
  44    MODE_MAX
  45 } mode = ORTHO;
  46
  47 static void Init(void)
  48 {
  49    fprintf(stderr, "GL_RENDERER   = %s\n", (char *) glGetString(GL_RENDERER));
  50    fprintf(stderr, "GL_VERSION    = %s\n", (char *) glGetString(GL_VERSION));
  51    fprintf(stderr, "GL_VENDOR     = %s\n", (char *) glGetString(GL_VENDOR));
  52    fflush(stderr);
  53
  54    glClearColor(0, 0, 0, 0.0);
  55 }
  56
  57 static void Reshape(int width, int height)
  58 {
  59    win_width = width;
  60    win_height = height;
  61    glutPostRedisplay();
  62 }
  63
  64
  65 static void Key(unsigned char key, int x, int y)
  66 {
  67    switch (key) {
  68    case 27:
  69       exit(0);
  70    case 'w':
  71       tw += 1.0;
  72       break;
  73    case 'W':
  74       tw -= 1.0;
  75       break;
  76    case 'h':
  77       th += 1.0;
  78       break;
  79    case 'H':
  80       th -= 1.0;
  81       break;
  82
  83    case 'z':
  84       z += 1.0;
  85       break;
  86    case 'Z':
  87       z -= 1.0;
  88       break;
  89    case 'm':
  90       mode++;
  91       mode %= MODE_MAX;
  92       break;
  93    case ' ':
  94       tw = th = tx = ty = 0;
  95       z = -5;
  96       mode = ORTHO;
  97       break;
  98    default:
  99       break;
 100    }
 101    glutPostRedisplay();
 102 }
 103
 104
 105 static void Draw(void)
 106 {
 107    int i;
 108    float w = tw + win_width;
 109    float h = th + win_height;
 110
 111    fprintf(stderr, "glViewport(%f %f %f %f)\n", tx, ty, w, h);
 112    fprintf(stderr, "mode: %s\n", mode == FRUSTUM ? "FRUSTUM" : "ORTHO");
 113    fprintf(stderr, "z: %f\n", z);
 114    fflush(stderr);
 115
 116    glMatrixMode(GL_PROJECTION);
 117    glLoadIdentity();
 118
 119    switch (mode) {
 120    case FRUSTUM:
 121       glFrustum(-1.0, 1.0, -1.0, 1.0, 5.0, 25.0);
 122       break;
 123    case ORTHO:
 124    default:
 125       glOrtho(-1.0, 1.0, -1.0, 1.0, -0.5, 1000.0);
 126       break;
 127    }
 128
 129    glMatrixMode(GL_MODELVIEW);
 130    glLoadIdentity();
 131
 132
 133    glClear(GL_COLOR_BUFFER_BIT);
 134
 135
 136    /***********************************************************************
 137     * Should be clipped to be no larger than the triangles:
 138     */
 139    glViewport(tx, ty, w, h);
 140
 141    glBegin(GL_POLYGON);
 142    glColor3f(1,1,0);
 143    glVertex3f(-100, -100, z);
 144    glVertex3f(-100, 100, z);
 145    glVertex3f(100, 100, z);
 146    glVertex3f(100, -100, z);
 147    glEnd();
 148
 149    glBegin(GL_POLYGON);
 150    glColor3f(0,1,1);
 151    glVertex3f(-10, -10, z);
 152    glVertex3f(-10, 10, z);
 153    glVertex3f(10, 10, z);
 154    glVertex3f(10, -10, z);
 155    glEnd();
 156
 157    glBegin(GL_POLYGON);
 158    glColor3f(1,0,0);
 159    glVertex3f(-2, -2, z);
 160    glVertex3f(-2, 2, z);
 161    glVertex3f(2, 2, z);
 162    glVertex3f(2, -2, z);
 163    glEnd();
 164
 165
 166    glBegin(GL_POLYGON);
 167    glColor3f(.5,.5,1);
 168    glVertex3f(-1, -1, z);
 169    glVertex3f(-1, 1, z);
 170    glVertex3f(1, 1, z);
 171    glVertex3f(1, -1, z);
 172    glEnd();
 173
 174    /***********************************************************************
 175     */
 176    glViewport(0, 0, win_width, win_height);
 177    glBegin(GL_LINES);
 178    glColor3f(1,1,0);
 179    glVertex3f(-1, 0, z);
 180    glVertex3f(1, 0, z);
 181
 182    glVertex3f(0,  -1, z);
 183    glVertex3f(0,  1, z);
 184    glEnd();
 185
 186
 187    /***********************************************************************
 188     */
 189    glViewport(tx, ty, w, h);
 190    glBegin(GL_TRIANGLES);
 191    glColor3f(1,0,0);
 192    glVertex3f(-1, -1, z);
 193    glVertex3f(0, -1, z);
 194    glVertex3f(-.5,  -.5, z);
 195
 196    glColor3f(1,1,1);
 197    glVertex3f(0, -1, z);
 198    glVertex3f(1, -1, z);
 199    glVertex3f(.5,  -.5, z);
 200
 201    glVertex3f(-.5, -.5, z);
 202    glVertex3f(.5, -.5, z);
 203    glVertex3f(0,  0, z);
 204
 205
 206    glColor3f(0,1,0);
 207    glVertex3f(1, 1, z);
 208    glVertex3f(0, 1, z);
 209    glVertex3f(.5,  .5, z);
 210
 211    glColor3f(1,1,1);
 212    glVertex3f(0, 1, z);
 213    glVertex3f(-1, 1, z);
 214    glVertex3f(-.5,  .5, z);
 215
 216    glVertex3f(.5, .5, z);
 217    glVertex3f(-.5, .5, z);
 218    glVertex3f( 0,  0, z);
 219
 220    glEnd();
 221
 222
 223    glViewport(0, 0, win_width, win_height);
 224
 225    glBegin(GL_LINES);
 226    glColor3f(.5,.5,0);
 227    for (i = -10; i < 10; i++) {
 228       float f = i / 10.0;
 229
 230       if (i == 0)
 231          continue;
 232
 233       glVertex3f(-1, f, z);
 234       glVertex3f(1, f, z);
 235
 236       glVertex3f(f, -1, z);
 237       glVertex3f(f, 1, z);
 238    }
 239    glEnd();
 240
 241
 242
 243    glFlush();
 244
 245    if (doubleBuffer) {
 246       glutSwapBuffers();
 247    }
 248 }
 249
 250 static GLenum Args(int argc, char **argv)
 251 {
 252    GLint i;
 253
 254    if (getenv("VPX"))
 255       tx = atof(getenv("VPX"));
 256
 257    if (getenv("VPY"))
 258       ty = atof(getenv("VPY"));
 259
 260
 261    for (i = 1; i < argc; i++) {
 262       if (strcmp(argv[i], "-sb") == 0) {
 263          doubleBuffer = GL_FALSE;
 264       } else if (strcmp(argv[i], "-db") == 0) {
 265          doubleBuffer = GL_TRUE;
 266       } else {
 267          fprintf(stderr, "%s (Bad option).\n", argv[i]);
 268          return GL_FALSE;
 269       }
 270    }
 271    return GL_TRUE;
 272 }
 273
 274
 275 static void
 276 special(int k, int x, int y)
 277 {
 278    switch (k) {
 279    case GLUT_KEY_UP:
 280       ty += 1.0;
 281       break;
 282    case GLUT_KEY_DOWN:
 283       ty -= 1.0;
 284       break;
 285    case GLUT_KEY_LEFT:
 286       tx -= 1.0;
 287       break;
 288    case GLUT_KEY_RIGHT:
 289       tx += 1.0;
 290       break;
 291    default:
 292       break;
 293    }
 294    glutPostRedisplay();
 295 }
 296
 297
 298 int main(int argc, char **argv)
 299 {
 300    GLenum type;
 301
 302    glutInit(&argc, argv);
 303
 304    if (Args(argc, argv) == GL_FALSE) {
 305       exit(1);
 306    }
 307
 308    glutInitWindowPosition(0, 0); glutInitWindowSize( 250, 250);
 309
 310    type = GLUT_RGB | GLUT_ALPHA;
 311    type |= (doubleBuffer) ? GLUT_DOUBLE : GLUT_SINGLE;
 312    glutInitDisplayMode(type);
 313
 314    win = glutCreateWindow(*argv);
 315    if (!win) {
 316       exit(1);
 317    }
 318
 319    Init();
 320
 321    glutReshapeFunc(Reshape);
 322    glutKeyboardFunc(Key);
 323    glutSpecialFunc(special);
 324    glutDisplayFunc(Draw);
 325    glutMainLoop();
 326    return 0;
 327 }