progs/trivial/line-smooth.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 <math.h>
  26 #include <stdio.h>
  27 #include <string.h>
  28 #include <stdlib.h>
  29 #include <GL/glut.h>
  30
  31
  32 #define CI_OFFSET_1 16
  33 #define CI_OFFSET_2 32
  34
  35
  36 GLenum doubleBuffer;
  37 GLboolean smooth = GL_TRUE;
  38 GLfloat width = 1.0;
  39
  40
  41 static void Init(void)
  42 {
  43    float range[2], aarange[2];
  44    fprintf(stderr, "GL_RENDERER   = %s\n", (char *) glGetString(GL_RENDERER));
  45    fprintf(stderr, "GL_VERSION    = %s\n", (char *) glGetString(GL_VERSION));
  46    fprintf(stderr, "GL_VENDOR     = %s\n", (char *) glGetString(GL_VENDOR));
  47    fflush(stderr);
  48    glGetFloatv(GL_LINE_WIDTH_RANGE, aarange);
  49    glGetFloatv(GL_ALIASED_LINE_WIDTH_RANGE, range);
  50    printf("Non-AA line width range: %f .. %f\n", range[0], range[1]);
  51    printf("AA line width range: %f .. %f\n", aarange[0], aarange[1]);
  52    fflush(stdout);
  53 }
  54
  55
  56 static void Reshape(int width, int height)
  57 {
  58    glViewport(0, 0, (GLint)width, (GLint)height);
  59    glMatrixMode(GL_PROJECTION);
  60    glLoadIdentity();
  61    glOrtho(-1.0, 1.0, -1.0, 1.0, -0.5, 1000.0);
  62    glMatrixMode(GL_MODELVIEW);
  63    glLoadIdentity();
  64    glTranslatef(0, 0, -30);
  65 }
  66
  67 static void Key(unsigned char key, int x, int y)
  68 {
  69    switch (key) {
  70    case 'w':
  71       width -= 0.5;
  72       if (width < 0.5)
  73          width = 0.5;
  74       break;
  75    case 'W':
  76       width += 0.5;
  77       break;
  78    case 's':
  79       smooth = !smooth;
  80       break;
  81    case 27:
  82       exit(1);
  83    default:
  84       return;
  85    }
  86    printf("LineWidth: %g\n", width);
  87    glutPostRedisplay();
  88 }
  89
  90
  91 static void Draw(void)
  92 {
  93    float a;
  94
  95    glClear(GL_COLOR_BUFFER_BIT);
  96
  97    glLineWidth(width);
  98
  99    if (smooth) {
 100       glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 101       glEnable(GL_BLEND);
 102       glEnable(GL_LINE_SMOOTH);
 103    }
 104
 105    glColor3f(1, 1, 1);
 106
 107    glBegin(GL_LINES);
 108    for (a = 0; a < 3.14159; a += 0.2) {
 109       float x = .9 * cos(a);
 110       float y = .9 * sin(a);
 111
 112       glVertex2f(-x, -y);
 113       glVertex2f( x,  y);
 114    }
 115    glEnd();
 116
 117    glDisable(GL_LINE_SMOOTH);
 118    glDisable(GL_BLEND);
 119
 120    glFlush();
 121
 122    if (doubleBuffer) {
 123       glutSwapBuffers();
 124    }
 125 }
 126
 127 static GLenum Args(int argc, char **argv)
 128 {
 129    GLint i;
 130
 131    doubleBuffer = GL_FALSE;
 132
 133    for (i = 1; i < argc; i++) {
 134       if (strcmp(argv[i], "-sb") == 0) {
 135          doubleBuffer = GL_FALSE;
 136       } else if (strcmp(argv[i], "-db") == 0) {
 137          doubleBuffer = GL_TRUE;
 138       } else {
 139          fprintf(stderr, "%s (Bad option).\n", argv[i]);
 140          return GL_FALSE;
 141       }
 142    }
 143    return GL_TRUE;
 144 }
 145
 146
 147 int main(int argc, char **argv)
 148 {
 149    GLenum type;
 150
 151    glutInit(&argc, argv);
 152
 153    if (Args(argc, argv) == GL_FALSE) {
 154       exit(1);
 155    }
 156
 157    glutInitWindowPosition(0, 0); glutInitWindowSize( 250, 250);
 158
 159    type = GLUT_RGB;
 160    type |= (doubleBuffer) ? GLUT_DOUBLE : GLUT_SINGLE;
 161    glutInitDisplayMode(type);
 162
 163    if (glutCreateWindow(argv[0]) == GL_FALSE) {
 164       exit(1);
 165    }
 166
 167    Init();
 168
 169    glutReshapeFunc(Reshape);
 170    glutKeyboardFunc(Key);
 171    glutDisplayFunc(Draw);
 172    glutMainLoop();
 173    return 0;
 174 }