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    fflush(stderr);
  43
  44     glClearColor(1.0, 1.0, 1.0, 0.0);
  45 }
  46
  47 static void Reshape(int width, int height)
  48 {
  49
  50     glViewport(0, 0, (GLint)width, (GLint)height);
  51
  52     glMatrixMode(GL_PROJECTION);
  53     glLoadIdentity();
  54     glOrtho(-1.0, 1.0, -1.0, 1.0, -0.5, 1000.0);
  55     glMatrixMode(GL_MODELVIEW);
  56 }
  57
  58 static void Key(unsigned char key, int x, int y)
  59 {
  60
  61     switch (key) {
  62       case 27:
  63         exit(1);
  64       default:
  65         break;
  66     }
  67
  68     glutPostRedisplay();
  69 }
  70
  71 static void Draw(void)
  72 {
  73    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  74    glEnable(GL_DEPTH_TEST);
  75
  76    glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
  77
  78
  79
  80    glEnable(GL_POLYGON_OFFSET_FILL);
  81    glPolygonOffset(1, 0);
  82
  83    glBegin(GL_QUADS);
  84    glColor3f(1,0,0);
  85    glVertex3f( 0.9, -0.9, -10.0);
  86    glVertex3f( 0.9,  0.9, -10.0);
  87    glVertex3f(-0.9,  0.9, -40.0);
  88    glVertex3f(-0.9,  -0.9, -40.0);
  89    glEnd();
  90
  91    glDisable(GL_POLYGON_OFFSET_FILL);
  92
  93    glBegin(GL_QUADS);
  94    glColor3f(0,1,0);
  95    glVertex3f( 0.6, -0.6, -15.0);
  96    glVertex3f( 0.6,  0.6, -15.0);
  97    glVertex3f(-0.6,  0.6, -35.0);
  98    glVertex3f(-0.6,  -0.6, -35.0);
  99    glEnd();
 100
 101    glEnable(GL_POLYGON_OFFSET_LINE);
 102    glPolygonOffset(-1, 0);
 103
 104    glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
 105
 106    glBegin(GL_QUADS);
 107    glColor3f(0,0,1);
 108    glVertex3f( 0.3, -0.3, -20.0);
 109    glVertex3f( 0.3,  0.3, -20.0);
 110    glVertex3f(-0.3,  0.3, -30.0);
 111    glVertex3f(-0.3,  -0.3, -30.0);
 112    glEnd();
 113
 114
 115    glDisable(GL_POLYGON_OFFSET_FILL);
 116
 117    glFlush();
 118
 119    if (doubleBuffer) {
 120       glutSwapBuffers();
 121    }
 122 }
 123
 124 static GLenum Args(int argc, char **argv)
 125 {
 126     GLint i;
 127
 128     doubleBuffer = GL_FALSE;
 129
 130     for (i = 1; i < argc; i++) {
 131         if (strcmp(argv[i], "-sb") == 0) {
 132             doubleBuffer = GL_FALSE;
 133         } else if (strcmp(argv[i], "-db") == 0) {
 134             doubleBuffer = GL_TRUE;
 135         } else {
 136             fprintf(stderr, "%s (Bad option).\n", argv[i]);
 137             return GL_FALSE;
 138         }
 139     }
 140     return GL_TRUE;
 141 }
 142
 143 int main(int argc, char **argv)
 144 {
 145     GLenum type;
 146
 147     glutInit(&argc, argv);
 148
 149     if (Args(argc, argv) == GL_FALSE) {
 150         exit(1);
 151     }
 152
 153     glutInitWindowPosition(0, 0); glutInitWindowSize( 250, 250);
 154
 155     type = GLUT_RGB | GLUT_ALPHA | GLUT_DEPTH;
 156     type |= (doubleBuffer) ? GLUT_DOUBLE : GLUT_SINGLE;
 157     glutInitDisplayMode(type);
 158
 159     if (glutCreateWindow(*argv) == GL_FALSE) {
 160         exit(1);
 161     }
 162
 163     Init();
 164
 165     glutReshapeFunc(Reshape);
 166     glutKeyboardFunc(Key);
 167     glutDisplayFunc(Draw);
 168     glutMainLoop();
 169         return 0;
 170 }