/*
* 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;
}