progs/trivial/quad-offset-unfilled.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
  31 #define CI_OFFSET_1 16
  32 #define CI_OFFSET_2 32
  33
  34
  35 GLenum doubleBuffer;
  36
  37 static 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
  43     glClearColor(1.0, 1.0, 1.0, 0.0);
  44 }
  45
  46 static 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, -0.5, 1000.0);
  54     glMatrixMode(GL_MODELVIEW);
  55 }
  56
  57 static void Key(unsigned char key, int x, int y)
  58 {
  59
  60     switch (key) {
  61       case 27:
  62         exit(1);
  63       default:
  64         return;
  65     }
  66
  67     glutPostRedisplay();
  68 }
  69
  70 static void Draw(void)
  71 {
  72    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  73    glEnable(GL_DEPTH_TEST);
  74
  75    glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
  76
  77
  78
  79    glEnable(GL_POLYGON_OFFSET_FILL);
  80    glPolygonOffset(1, 0);
  81
  82    glBegin(GL_QUADS);
  83    glColor3f(1,0,0);
  84    glVertex3f( 0.9, -0.9, -10.0);
  85    glVertex3f( 0.9,  0.9, -10.0);
  86    glVertex3f(-0.9,  0.9, -40.0);
  87    glVertex3f(-0.9,  -0.9, -40.0);
  88    glEnd();
  89
  90    glDisable(GL_POLYGON_OFFSET_FILL);
  91
  92    glBegin(GL_QUADS);
  93    glColor3f(0,1,0);
  94    glVertex3f( 0.6, -0.6, -15.0);
  95    glVertex3f( 0.6,  0.6, -15.0);
  96    glVertex3f(-0.6,  0.6, -35.0);
  97    glVertex3f(-0.6,  -0.6, -35.0);
  98    glEnd();
  99
 100    glEnable(GL_POLYGON_OFFSET_LINE);
 101    glPolygonOffset(-1, 0);
 102
 103    glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
 104
 105    glBegin(GL_QUADS);
 106    glColor3f(0,0,1);
 107    glVertex3f( 0.3, -0.3, -20.0);
 108    glVertex3f( 0.3,  0.3, -20.0);
 109    glVertex3f(-0.3,  0.3, -30.0);
 110    glVertex3f(-0.3,  -0.3, -30.0);
 111    glEnd();
 112
 113
 114    glDisable(GL_POLYGON_OFFSET_FILL);
 115
 116    glFlush();
 117
 118    if (doubleBuffer) {
 119       glutSwapBuffers();
 120    }
 121 }
 122
 123 static GLenum Args(int argc, char **argv)
 124 {
 125     GLint i;
 126
 127     doubleBuffer = GL_FALSE;
 128
 129     for (i = 1; i < argc; i++) {
 130         if (strcmp(argv[i], "-sb") == 0) {
 131             doubleBuffer = GL_FALSE;
 132         } else if (strcmp(argv[i], "-db") == 0) {
 133             doubleBuffer = GL_TRUE;
 134         } else {
 135             fprintf(stderr, "%s (Bad option).\n", argv[i]);
 136             return GL_FALSE;
 137         }
 138     }
 139     return GL_TRUE;
 140 }
 141
 142 int main(int argc, char **argv)
 143 {
 144     GLenum type;
 145
 146     glutInit(&argc, argv);
 147
 148     if (Args(argc, argv) == GL_FALSE) {
 149         exit(1);
 150     }
 151
 152     glutInitWindowPosition(0, 0); glutInitWindowSize( 250, 250);
 153
 154     type = GLUT_RGB | GLUT_ALPHA | GLUT_DEPTH;
 155     type |= (doubleBuffer) ? GLUT_DOUBLE : GLUT_SINGLE;
 156     glutInitDisplayMode(type);
 157
 158     if (glutCreateWindow("First Tri") == GL_FALSE) {
 159         exit(1);
 160     }
 161
 162     Init();
 163
 164     glutReshapeFunc(Reshape);
 165     glutKeyboardFunc(Key);
 166     glutDisplayFunc(Draw);
 167     glutMainLoop();
 168         return 0;
 169 }