progs/demos/winpos.c

   1 /* $Id: winpos.c,v 1.1 1999/08/19 00:55:40 jtg Exp $ */
   2
   3 /*
   4  * Example of how to use the GL_MESA_window_pos extension.
   5  * Brian Paul   This file is in the public domain.
   6  */
   7
   8
   9 /*
  10  * $Log: winpos.c,v $
  11  * Revision 1.1  1999/08/19 00:55:40  jtg
  12  * Initial revision
  13  *
  14  * Revision 3.3  1999/03/28 18:24:37  brianp
  15  * minor clean-up
  16  *
  17  * Revision 3.2  1998/11/05 04:34:04  brianp
  18  * moved image files to ../images/ directory
  19  *
  20  * Revision 3.1  1998/02/22 16:36:10  brianp
  21  * changed image file and set unpack alignment to 1
  22  *
  23  * Revision 3.0  1998/02/14 18:42:29  brianp
  24  * initial rev
  25  *
  26  */
  27
  28
  29 #include <math.h>
  30 #include <string.h>
  31 #include <stdlib.h>
  32 #include <stdio.h>
  33 #include "GL/glut.h"
  34
  35 #include "../util/readtex.c"  /* a hack, I know */
  36
  37 #define IMAGE_FILE "../images/girl.rgb"
  38
  39
  40 #ifndef M_PI
  41 #  define M_PI 3.14159265
  42 #endif
  43
  44
  45
  46 static GLubyte *Image;
  47 static int ImgWidth, ImgHeight;
  48 static GLenum ImgFormat;
  49
  50
  51
  52 static void draw( void )
  53 {
  54    GLfloat angle;
  55    char *extensions;
  56
  57    extensions = (char *) glGetString( GL_EXTENSIONS );
  58    if (strstr( extensions, "GL_MESA_window_pos")==NULL) {
  59       printf("Sorry, GL_MESA_window_pos extension not available.\n");
  60       return;
  61    }
  62
  63    glClear( GL_COLOR_BUFFER_BIT );
  64
  65    for (angle = -45.0; angle <= 135.0; angle += 10.0) {
  66       GLfloat x = 50.0 + 200.0 * cos( angle * M_PI / 180.0 );
  67       GLfloat y = 50.0 + 200.0 * sin( angle * M_PI / 180.0 );
  68
  69       /* Don't need to worry about the modelview or projection matrices!!! */
  70 #ifdef GL_MESA_window_pos
  71       glWindowPos2fMESA( x, y );
  72 #endif
  73       glDrawPixels( ImgWidth, ImgHeight, ImgFormat, GL_UNSIGNED_BYTE, Image );
  74    }
  75 }
  76
  77
  78
  79
  80 static void key( unsigned char key, int x, int y )
  81 {
  82    (void) x;
  83    (void) y;
  84    switch (key) {
  85       case 27:
  86          exit(0);
  87    }
  88 }
  89
  90
  91
  92 /* new window size or exposure */
  93 static void reshape( int width, int height )
  94 {
  95    glViewport(0, 0, (GLint)width, (GLint)height);
  96 }
  97
  98
  99 static void init( void )
 100 {
 101    Image = LoadRGBImage( IMAGE_FILE, &ImgWidth, &ImgHeight, &ImgFormat );
 102    if (!Image) {
 103       printf("Couldn't read %s\n", IMAGE_FILE);
 104       exit(0);
 105    }
 106    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
 107 }
 108
 109
 110
 111 int main( int argc, char *argv[] )
 112 {
 113    glutInitWindowPosition(0, 0);
 114    glutInitWindowSize(500, 500);
 115    glutInitDisplayMode( GLUT_RGB );
 116
 117    if (glutCreateWindow("winpos") <= 0) {
 118       exit(0);
 119    }
 120
 121    init();
 122
 123    glutReshapeFunc( reshape );
 124    glutKeyboardFunc( key );
 125    glutDisplayFunc( draw );
 126    glutMainLoop();
 127    return 0;
 128 }