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File: [Development] / projects / ogl-sample / main / gfx / samples / redbook_2ed / image.c (download)

Revision 1.2, Wed Apr 5 06:43:46 2000 UTC (17 years, 6 months ago) by ljp
Branch: MAIN
CVS Tags: tested_with_xf86_3_3, HEAD
Changes since 1.1: +1 -1 lines

Change license version to 1.1.

/*
 * License Applicability. Except to the extent portions of this file are
 * made subject to an alternative license as permitted in the SGI Free
 * Software License B, Version 1.1 (the "License"), the contents of this
 * file are subject only to the provisions of the License. You may not use
 * this file except in compliance with the License. You may obtain a copy
 * of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
 * Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
 * 
 * http://oss.sgi.com/projects/FreeB
 * 
 * Note that, as provided in the License, the Software is distributed on an
 * "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
 * DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
 * CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
 * PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
 * 
 * Original Code. The Original Code is: OpenGL Sample Implementation,
 * Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
 * Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
 * Copyright in any portions created by third parties is as indicated
 * elsewhere herein. All Rights Reserved.
 * 
 * Additional Notice Provisions: The application programming interfaces
 * established by SGI in conjunction with the Original Code are The
 * OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
 * April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
 * 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
 * Window System(R) (Version 1.3), released October 19, 1998. This software
 * was created using the OpenGL(R) version 1.2.1 Sample Implementation
 * published by SGI, but has not been independently verified as being
 * compliant with the OpenGL(R) version 1.2.1 Specification.
 *
 */

/*  image.c
 *  This program demonstrates drawing pixels and shows the effect
 *  of glDrawPixels(), glCopyPixels(), and glPixelZoom().
 *  Interaction: moving the mouse while pressing the mouse button
 *  will copy the image in the lower-left corner of the window
 *  to the mouse position, using the current pixel zoom factors.
 *  There is no attempt to prevent you from drawing over the original
 *  image.  If you press the 'r' key, the original image and zoom
 *  factors are reset.  If you press the 'z' or 'Z' keys, you change
 *  the zoom factors.
 */
#include <GL/glut.h>
#include <stdlib.h>
#include <stdio.h>

/*	Create checkerboard image	*/
#define	checkImageWidth 64
#define	checkImageHeight 64
GLubyte checkImage[checkImageHeight][checkImageWidth][3];

static GLdouble zoomFactor = 1.0;
static GLint height;

void makeCheckImage(void)
{
   int i, j, c;
    
   for (i = 0; i < checkImageHeight; i++) {
      for (j = 0; j < checkImageWidth; j++) {
         c = ((((i&0x8)==0)^((j&0x8))==0))*255;
         checkImage[i][j][0] = (GLubyte) c;
         checkImage[i][j][1] = (GLubyte) c;
         checkImage[i][j][2] = (GLubyte) c;
      }
   }
}

void init(void)
{    
   glClearColor (0.0, 0.0, 0.0, 0.0);
   glShadeModel(GL_FLAT);
   makeCheckImage();
   glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
}

void display(void)
{
   glClear(GL_COLOR_BUFFER_BIT);
   glRasterPos2i(0, 0);
   glDrawPixels(checkImageWidth, checkImageHeight, GL_RGB, 
                GL_UNSIGNED_BYTE, checkImage);
   glFlush();
}

void reshape(int w, int h)
{
   glViewport(0, 0, (GLsizei) w, (GLsizei) h);
   height = (GLint) h;
   glMatrixMode(GL_PROJECTION);
   glLoadIdentity();
   gluOrtho2D(0.0, (GLdouble) w, 0.0, (GLdouble) h);
   glMatrixMode(GL_MODELVIEW);
   glLoadIdentity();
}

void motion(int x, int y)
{
   static GLint screeny;
   
   screeny = height - (GLint) y;
   glRasterPos2i (x, screeny);
   glPixelZoom (zoomFactor, zoomFactor);
   glCopyPixels (0, 0, checkImageWidth, checkImageHeight, GL_COLOR);
   glPixelZoom (1.0, 1.0);
   glFlush ();
}

void keyboard(unsigned char key, int x, int y)
{
   switch (key) {
      case 'r':
      case 'R':
         zoomFactor = 1.0;
         glutPostRedisplay();
         printf ("zoomFactor reset to 1.0\n");
         break;
      case 'z':
         zoomFactor += 0.5;
         if (zoomFactor >= 3.0) 
            zoomFactor = 3.0;
         printf ("zoomFactor is now %4.1f\n", zoomFactor);
         break;
      case 'Z':
         zoomFactor -= 0.5;
         if (zoomFactor <= 0.5) 
            zoomFactor = 0.5;
         printf ("zoomFactor is now %4.1f\n", zoomFactor);
         break;
      case 27:
         exit(0);
         break;
      default:
         break;
   }
}

int main(int argc, char** argv)
{
   glutInit(&argc, argv);
   glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
   glutInitWindowSize(250, 250);
   glutInitWindowPosition(100, 100);
   glutCreateWindow(argv[0]);
   init();
   glutDisplayFunc(display);
   glutReshapeFunc(reshape);
   glutKeyboardFunc(keyboard);
   glutMotionFunc(motion);
   glutMainLoop();
   return 0; 
}