progs/tests/lineclip.c

   1 /*
   2  * Copyright © 2008 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  *
  23  * Authors:
  24  *    Eric Anholt <eric@anholt.net>
  25  *
  26  */
  27
  28 #include <stdlib.h>
  29 #include <GL/glut.h>
  30
  31 static int win_width, win_height;
  32
  33 static void
  34 line(GLfloat x1, GLfloat y1, GLfloat x2, GLfloat y2)
  35 {
  36         glBegin(GL_LINES);
  37         glVertex2f(x1, y1);
  38         glVertex2f(x2, y2);
  39         glEnd();
  40 }
  41
  42 static void
  43 line3(GLfloat x1, GLfloat y1, GLfloat z1, GLfloat x2, GLfloat y2, GLfloat z2)
  44 {
  45         glBegin(GL_LINES);
  46         glVertex3f(x1, y1, z1);
  47         glVertex3f(x2, y2, z2);
  48         glEnd();
  49 }
  50
  51 static void
  52 display(void)
  53 {
  54         glClearColor(0.0, 0.0, 0.0, 0.0);
  55         glClear(GL_COLOR_BUFFER_BIT);
  56
  57         glColor3f(1.0, 0.0, 0.0);
  58         /* 2 lines clipped along xmin */
  59         line(-20, win_height / 2 - 20,
  60               20, win_height / 2 - 20);
  61         line( 20, win_height / 2 + 20,
  62              -20, win_height / 2 + 20);
  63
  64         glColor3f(0.0, 1.0, 0.0);
  65         /* 2 lines clipped along ymax */
  66         line(win_width / 2 - 20, win_height + 20,
  67              win_width / 2 - 20, win_height - 20);
  68         line(win_width / 2 + 20, win_height - 20,
  69              win_width / 2 + 20, win_height + 20);
  70
  71         glColor3f(0.0, 0.0, 1.0);
  72         /* 2 lines clipped along xmax */
  73         line(win_width - 20, win_height / 2 - 20,
  74              win_width + 20, win_height / 2 - 20);
  75         line(win_width + 20, win_height / 2 + 20,
  76              win_width - 20, win_height / 2 + 20);
  77
  78         glColor3f(1.0, 1.0, 1.0);
  79         /* 2 lines clipped along ymin */
  80         line(win_width / 2 - 20,  20,
  81              win_width / 2 - 20, -20);
  82         line(win_width / 2 + 20, -20,
  83              win_width / 2 + 20,  20);
  84
  85         /* 2 lines clipped along near */
  86         glColor3f(1.0, 0.0, 1.0);
  87         line3(win_width / 2 - 20 - 20, win_height / 2,       0.5,
  88               win_width / 2 - 20 + 20, win_height / 2,      -0.5);
  89         line3(win_width / 2 - 20,      win_height / 2 - 20, -0.5,
  90               win_width / 2 - 20,      win_height / 2 + 20,  0.5);
  91
  92         /* 2 lines clipped along far */
  93         glColor3f(0.0, 1.0, 1.0);
  94         line3(win_width / 2 + 20 - 20, win_height / 2,      1.5,
  95               win_width / 2 + 20 + 20, win_height / 2,      0.5);
  96         line3(win_width / 2 + 20,      win_height / 2 - 20, 0.5,
  97               win_width / 2 + 20,      win_height / 2 + 20, 1.5);
  98
  99         /* entirely clipped along near/far */
 100         glColor3f(.5, .5, .5);
 101         line3(win_width / 2, win_height / 2 - 20, -0.5,
 102               win_width / 2, win_height / 2 + 20, -0.5);
 103         glColor3f(.5, .5, .5);
 104         line3(win_width / 2, win_height / 2 - 20, 1.5,
 105               win_width / 2, win_height / 2 + 20, 1.5);
 106
 107         glColor3f(1.0, 1.0, 0.0);
 108         /* lines clipped along both x and y limits */
 109         line(-5, 20,
 110              20, -5); /* xmin, ymin */
 111         line(-5, win_height - 20,
 112              20, win_height + 5); /* xmin, ymax */
 113         line(win_width - 20, -5,
 114              win_width + 5,  20); /* xmax, ymin */
 115         line(win_width - 20, win_height + 5,
 116              win_width + 5,  win_height - 20); /* xmax, ymax */
 117
 118         glutSwapBuffers();
 119 }
 120
 121 static void
 122 reshape(int width, int height)
 123 {
 124         win_width = width;
 125         win_height = height;
 126         glViewport(0, 0, width, height);
 127
 128         glMatrixMode(GL_PROJECTION);
 129         glLoadIdentity();
 130         glOrtho(0, win_width, 0, win_height, 0.0, -1.0);
 131
 132         glMatrixMode(GL_MODELVIEW);
 133         glLoadIdentity();
 134         glTranslatef(.25, .25, 0);
 135 }
 136
 137 static void key( unsigned char key, int x, int y )
 138 {
 139         (void) x;
 140         (void) y;
 141
 142         switch (key) {
 143         case 27: /* esc */
 144                 exit(0);
 145                 break;
 146         }
 147
 148         glutPostRedisplay();
 149 }
 150
 151 static void
 152 init(void)
 153 {
 154 }
 155
 156 int
 157 main(int argc, char *argv[])
 158 {
 159         win_width = 200;
 160         win_height = 200;
 161
 162         glutInit(&argc, argv);
 163         glutInitWindowPosition(0, 0);
 164         glutInitWindowSize(win_width, win_height);
 165         glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
 166         glutCreateWindow(argv[0]);
 167         glutReshapeFunc(reshape);
 168         glutKeyboardFunc(key);
 169         glutDisplayFunc(display);
 170
 171         init();
 172
 173         glutMainLoop();
 174         return 0;
 175 }