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/glew.h>
  30 #include <GL/glut.h>
  31
  32 static int win_width, win_height;
  33
  34 static void
  35 line(GLfloat x1, GLfloat y1, GLfloat x2, GLfloat y2)
  36 {
  37         glBegin(GL_LINES);
  38         glVertex2f(x1, y1);
  39         glVertex2f(x2, y2);
  40         glEnd();
  41 }
  42
  43 static void
  44 line3(GLfloat x1, GLfloat y1, GLfloat z1, GLfloat x2, GLfloat y2, GLfloat z2)
  45 {
  46         glBegin(GL_LINES);
  47         glVertex3f(x1, y1, z1);
  48         glVertex3f(x2, y2, z2);
  49         glEnd();
  50 }
  51
  52 static void
  53 display(void)
  54 {
  55         glClearColor(0.0, 0.0, 0.0, 0.0);
  56         glClear(GL_COLOR_BUFFER_BIT);
  57
  58         glColor3f(1.0, 0.0, 0.0);
  59         /* 2 lines clipped along xmin */
  60         line(-20, win_height / 2 - 20,
  61               20, win_height / 2 - 20);
  62         line( 20, win_height / 2 + 20,
  63              -20, win_height / 2 + 20);
  64
  65         glColor3f(0.0, 1.0, 0.0);
  66         /* 2 lines clipped along ymax */
  67         line(win_width / 2 - 20, win_height + 20,
  68              win_width / 2 - 20, win_height - 20);
  69         line(win_width / 2 + 20, win_height - 20,
  70              win_width / 2 + 20, win_height + 20);
  71
  72         glColor3f(0.0, 0.0, 1.0);
  73         /* 2 lines clipped along xmax */
  74         line(win_width - 20, win_height / 2 - 20,
  75              win_width + 20, win_height / 2 - 20);
  76         line(win_width + 20, win_height / 2 + 20,
  77              win_width - 20, win_height / 2 + 20);
  78
  79         glColor3f(1.0, 1.0, 1.0);
  80         /* 2 lines clipped along ymin */
  81         line(win_width / 2 - 20,  20,
  82              win_width / 2 - 20, -20);
  83         line(win_width / 2 + 20, -20,
  84              win_width / 2 + 20,  20);
  85
  86         /* 2 lines clipped along near */
  87         glColor3f(1.0, 0.0, 1.0);
  88         line3(win_width / 2 - 20 - 20, win_height / 2,       0.5,
  89               win_width / 2 - 20 + 20, win_height / 2,      -0.5);
  90         line3(win_width / 2 - 20,      win_height / 2 - 20, -0.5,
  91               win_width / 2 - 20,      win_height / 2 + 20,  0.5);
  92
  93         /* 2 lines clipped along far */
  94         glColor3f(0.0, 1.0, 1.0);
  95         line3(win_width / 2 + 20 - 20, win_height / 2,      1.5,
  96               win_width / 2 + 20 + 20, win_height / 2,      0.5);
  97         line3(win_width / 2 + 20,      win_height / 2 - 20, 0.5,
  98               win_width / 2 + 20,      win_height / 2 + 20, 1.5);
  99
 100         /* entirely clipped along near/far */
 101         glColor3f(.5, .5, .5);
 102         line3(win_width / 2, win_height / 2 - 20, -0.5,
 103               win_width / 2, win_height / 2 + 20, -0.5);
 104         glColor3f(.5, .5, .5);
 105         line3(win_width / 2, win_height / 2 - 20, 1.5,
 106               win_width / 2, win_height / 2 + 20, 1.5);
 107
 108         glColor3f(1.0, 1.0, 0.0);
 109         /* lines clipped along both x and y limits */
 110         line(-5, 20,
 111              20, -5); /* xmin, ymin */
 112         line(-5, win_height - 20,
 113              20, win_height + 5); /* xmin, ymax */
 114         line(win_width - 20, -5,
 115              win_width + 5,  20); /* xmax, ymin */
 116         line(win_width - 20, win_height + 5,
 117              win_width + 5,  win_height - 20); /* xmax, ymax */
 118
 119         glutSwapBuffers();
 120 }
 121
 122 static void
 123 reshape(int width, int height)
 124 {
 125         win_width = width;
 126         win_height = height;
 127         glViewport(0, 0, width, height);
 128
 129         glMatrixMode(GL_PROJECTION);
 130         glLoadIdentity();
 131         glOrtho(0, win_width, 0, win_height, 0.0, -1.0);
 132
 133         glMatrixMode(GL_MODELVIEW);
 134         glLoadIdentity();
 135         glTranslatef(.25, .25, 0);
 136 }
 137
 138 static void key( unsigned char key, int x, int y )
 139 {
 140         (void) x;
 141         (void) y;
 142
 143         switch (key) {
 144         case 27: /* esc */
 145                 exit(0);
 146                 break;
 147         }
 148
 149         glutPostRedisplay();
 150 }
 151
 152 static void
 153 init(void)
 154 {
 155 }
 156
 157 int
 158 main(int argc, char *argv[])
 159 {
 160         win_width = 200;
 161         win_height = 200;
 162
 163         glutInit(&argc, argv);
 164         glutInitWindowPosition(0, 0);
 165         glutInitWindowSize(win_width, win_height);
 166         glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
 167         glutCreateWindow(argv[0]);
 168         glewInit();
 169         glutReshapeFunc(reshape);
 170         glutKeyboardFunc(key);
 171         glutDisplayFunc(display);
 172
 173         init();
 174
 175         glutMainLoop();
 176         return 0;
 177 }