progs/redbook/convolution.c

   1 /*
   2  * Copyright (c) 1993-2003, Silicon Graphics, Inc.
   3  * All Rights Reserved
   4  *
   5  * Permission to use, copy, modify, and distribute this software for any
   6  * purpose and without fee is hereby granted, provided that the above
   7  * copyright notice appear in all copies and that both the copyright
   8  * notice and this permission notice appear in supporting documentation,
   9  * and that the name of Silicon Graphics, Inc. not be used in
  10  * advertising or publicity pertaining to distribution of the software
  11  * without specific, written prior permission.
  12  *
  13  * THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS" AND
  14  * WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR
  16  * FITNESS FOR A PARTICULAR PURPOSE.  IN NO EVENT SHALL SILICON
  17  * GRAPHICS, INC.  BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT,
  18  * SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
  19  * OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION, LOSS OF
  20  * PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF THIRD
  21  * PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC.  HAS BEEN ADVISED OF
  22  * THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON ANY THEORY OF
  23  * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE POSSESSION, USE
  24  * OR PERFORMANCE OF THIS SOFTWARE.
  25  *
  26  * US Government Users Restricted Rights
  27  * Use, duplication, or disclosure by the Government is subject to
  28  * restrictions set forth in FAR 52.227.19(c)(2) or subparagraph
  29  * (c)(1)(ii) of the Rights in Technical Data and Computer Software
  30  * clause at DFARS 252.227-7013 and/or in similar or successor clauses
  31  * in the FAR or the DOD or NASA FAR Supplement.  Unpublished - rights
  32  * reserved under the copyright laws of the United States.
  33  *
  34  * Contractor/manufacturer is:
  35  *      Silicon Graphics, Inc.
  36  *      1500 Crittenden Lane
  37  *      Mountain View, CA  94043
  38  *      United State of America
  39  *
  40  * OpenGL(R) is a registered trademark of Silicon Graphics, Inc.
  41  */
  42
  43 /*
  44  *  convolution.c
  45  *  Use various 2D convolutions filters to find edges in an image.
  46  *
  47  */
  48 #include <GL/glew.h>
  49 #include <GL/glut.h>
  50 #include <assert.h>
  51 #include <stdio.h>
  52 #include <stdlib.h>
  53
  54
  55 static GLuint bswap(GLuint x)
  56 {
  57    const GLuint ui = 1;
  58    const GLubyte *ubp = (const GLubyte *) &ui;
  59    if (*ubp == 1) {
  60       /* we're on little endiang so byteswap x */
  61       GLsizei y =  ((x >> 24)
  62                     | ((x >> 8) & 0xff00)
  63                     | ((x << 8) & 0xff0000)
  64                     | ((x << 24) & 0xff000000));
  65       return y;
  66    }
  67    else {
  68       return x;
  69    }
  70 }
  71
  72
  73 static GLubyte *
  74 readImage( const char* filename, GLsizei* width, GLsizei *height )
  75 {
  76     int       n;
  77     GLubyte*  pixels;
  78     size_t    num_read;
  79
  80     FILE* infile = fopen( filename, "rb" );
  81
  82     if ( !infile ) {
  83         fprintf( stderr, "Unable to open file '%s'\n", filename );
  84         exit(1);
  85     }
  86
  87     num_read = fread( width, sizeof( GLsizei ), 1, infile );
  88     assert(num_read == 1);
  89     num_read = fread( height, sizeof( GLsizei ), 1, infile );
  90     assert(num_read == 1);
  91
  92     *width = bswap(*width);
  93     *height = bswap(*height);
  94
  95     assert(*width > 0);
  96     assert(*height > 0);
  97
  98     n = 3 * (*width) * (*height);
  99
 100     pixels = (GLubyte *) malloc( n * sizeof( GLubyte ));
 101     if ( !pixels ) {
 102         fprintf( stderr, "Unable to malloc() bytes for pixels\n" );
 103         fclose( infile );
 104         return NULL;
 105     }
 106
 107     num_read = fread( pixels, sizeof( GLubyte ), n, infile );
 108     assert(num_read == n);
 109
 110     fclose( infile );
 111
 112     return pixels;
 113 }
 114
 115
 116 GLubyte  *pixels;
 117 GLsizei   width, height;
 118
 119 GLfloat  horizontal[3][3] = {
 120     { 0, -1, 0 },
 121     { 0,  1, 0 },
 122     { 0,  0, 0 }
 123 };
 124
 125 GLfloat  vertical[3][3] = {
 126     {  0, 0, 0 },
 127     { -1, 1, 0 },
 128     {  0, 0, 0 }
 129 };
 130
 131 GLfloat  laplacian[3][3] = {
 132     { -0.125, -0.125, -0.125 },
 133     { -0.125,  1.0  , -0.125 },
 134     { -0.125, -0.125, -0.125 },
 135 };
 136
 137
 138 static void init(void)
 139 {
 140    if (!glutExtensionSupported("GL_ARB_imaging")) {
 141       fprintf(stderr, "Sorry, this program requires GL_ARB_imaging.\n");
 142       exit(1);
 143    }
 144
 145    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
 146    glClearColor(0.0, 0.0, 0.0, 0.0);
 147
 148    printf("Using the horizontal filter\n");
 149    glConvolutionFilter2D(GL_CONVOLUTION_2D, GL_LUMINANCE,
 150                          3, 3, GL_LUMINANCE, GL_FLOAT, horizontal);
 151    glEnable(GL_CONVOLUTION_2D);
 152 }
 153
 154 static void display(void)
 155 {
 156    glClear(GL_COLOR_BUFFER_BIT);
 157    glRasterPos2i( 1, 1);
 158    glDrawPixels(width, height, GL_RGB, GL_UNSIGNED_BYTE, pixels);
 159    glFlush();
 160 }
 161
 162 static void reshape(int w, int h)
 163 {
 164    glViewport(0, 0, (GLsizei) w, (GLsizei) h);
 165    glMatrixMode(GL_PROJECTION);
 166    glLoadIdentity();
 167    glOrtho(0, w, 0, h, -1.0, 1.0);
 168    glMatrixMode(GL_MODELVIEW);
 169 }
 170
 171 static void keyboard(unsigned char key, int x, int y)
 172 {
 173    switch (key) {
 174        case 'h' :
 175            printf("Using a horizontal filter\n");
 176            glConvolutionFilter2D(GL_CONVOLUTION_2D, GL_LUMINANCE, 3, 3,
 177                                   GL_LUMINANCE, GL_FLOAT, horizontal);
 178            break;
 179
 180        case 'v' :
 181            printf("Using the vertical filter\n");
 182            glConvolutionFilter2D(GL_CONVOLUTION_2D, GL_LUMINANCE, 3, 3,
 183                                   GL_LUMINANCE, GL_FLOAT, vertical);
 184            break;
 185
 186        case 'l' :
 187            printf("Using the laplacian filter\n");
 188            glConvolutionFilter2D(GL_CONVOLUTION_2D, GL_LUMINANCE, 3, 3,
 189                                   GL_LUMINANCE, GL_FLOAT, laplacian);
 190            break;
 191
 192        case 27:
 193          exit(0);
 194    }
 195    glutPostRedisplay();
 196 }
 197
 198 /*  Main Loop
 199  *  Open window with initial window size, title bar,
 200  *  RGBA display mode, and handle input events.
 201  */
 202 int main(int argc, char** argv)
 203 {
 204    pixels = readImage("leeds.bin", &width, &height);
 205
 206    glutInit(&argc, argv);
 207    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGBA);
 208    glutInitWindowSize(width, height);
 209    glutInitWindowPosition(100, 100);
 210    glutCreateWindow(argv[0]);
 211    glewInit();
 212    init();
 213    glutReshapeFunc(reshape);
 214    glutKeyboardFunc(keyboard);
 215    glutDisplayFunc(display);
 216    glutMainLoop();
 217    return 0;
 218 }