Added "offscreen" demo, a very simple program that produces an onscreen
window and, upon command, renders a similar offscreen display and writes the result to disk. Also, modified the build structure for UNIX_X11 to autobuild the demo. (Not done for WIN32 at this time.) Also, forgot to previously commit the updated freeglut_ext.h include. Eeep. git-svn-id: https://svn.code.sf.net/p/freeglut/code/trunk@465 7f0cb862-5218-0410-a997-914c9d46530a
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rkrolib
parent
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commit
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2
.gitattributes
vendored
2
.gitattributes
vendored
@ -53,6 +53,8 @@ freeglut/freeglut/progs/demos/One/Makefile.am svn_keywords=Author+Date+Id+Revisi
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freeglut/freeglut/progs/demos/One/one.c svn_keywords=Author+Date+Id+Revision
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freeglut/freeglut/progs/demos/One/one.dsp svn_keywords=Author+Date+Id+Revision
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freeglut/freeglut/progs/demos/demos.dsw svn_keywords=Author+Date+Id+Revision
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freeglut/freeglut/progs/demos/offscreen/Makefile.am svn_keywords=Author+Date+Id+Revision
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freeglut/freeglut/progs/demos/offscreen/offscreen.c svn_keywords=Author+Date+Id+Revision
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freeglut/freeglut/progs/demos/shapes/Makefile.am svn_keywords=Author+Date+Id+Revision
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freeglut/freeglut/progs/demos/shapes/shapes.c svn_keywords=Author+Date+Id+Revision
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freeglut/freeglut/progs/demos/shapes/shapes.dsp svn_keywords=Author+Date+Id+Revision
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@ -67,6 +67,7 @@ AC_OUTPUT(\
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progs/demos/Fractals_random/Makefile \
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progs/demos/Lorenz/Makefile \
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progs/demos/One/Makefile \
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progs/demos/offscreen/Makefile \
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progs/demos/shapes/Makefile \
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src/Makefile \
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include/Makefile \
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@ -45,6 +45,11 @@
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#define GLUT_CREATE_NEW_CONTEXT 0
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#define GLUT_USE_CURRENT_CONTEXT 1
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/*
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* GLUT API Extension macro definitions -- display mode
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*/
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#define GLUT_OFFSCREEN 0x0400
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/*
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* GLUT API Extension macro definitions -- the glutGet parameters
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*/
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@ -1,2 +1,2 @@
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EXTRA_DIST = demos.dsw
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SUBDIRS = CallbackMaker Fractals Fractals_random Lorenz One shapes
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SUBDIRS = CallbackMaker Fractals Fractals_random Lorenz offscreen One shapes
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5
freeglut/freeglut/progs/demos/offscreen/Makefile.am
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5
freeglut/freeglut/progs/demos/offscreen/Makefile.am
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@ -0,0 +1,5 @@
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EXTRA_DIST = shapes.c shapes.dsp
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noinst_PROGRAMS = offscreen
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offscreen_SOURCES = offscreen.c
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offscreen_LDFLAGS = -export-dynamic ../../../src/lib@LIBRARY@.la
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offscreen_CFLAGS = -I$(top_srcdir)/include $(X_CFLAGS)
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172
freeglut/freeglut/progs/demos/offscreen/offscreen.c
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172
freeglut/freeglut/progs/demos/offscreen/offscreen.c
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@ -0,0 +1,172 @@
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/*
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* freeglut offscreen rendering demo.
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*
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* Usage:
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*
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* offscreen [standard GLUT options] [filename]
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*
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* The filename is used to say where to write a PNM image file
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* that is the sole way to verify that this program is doing what
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* it should (i.e., rendering offscreen).
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*
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* You can view the PNM file in image viewers and editors such as
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* the GIMP. (Everyone doing any kind of graphics has at least one
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* multi-format-reading image manipulation program, right?)
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*
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* If no filename is specified, the chosen filename is "offscreen.pnm".
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*
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* Some suggested uses for GLUT_OFFSCREEN:
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*
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* * Implementation of a graphics language that writes bitmapped image files.
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* * Capture GLUT bitmapped fonts to a texture at runtime to make scalable
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* bitmapped fonts.
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* * Using OpenGL to create special-effect textures at run-time.
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* * Making stencils.
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* * Getting the depth-buffer for a height-field.
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* * Using OpenGL to create a poster texture (e.g., for pasting onto a a
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* video screen in a virtual world).
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* * Using OpenGL to prescale an image to a power-of-2 dimension (including
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* OpenGL antialiasing). There's no reason that you couldn't do this
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* yourself, but OpenGL can do it for you, so why not?
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* * Rendering to a bitmap larger than the display has been suggested
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* as well. This is a cheap way to produce arbitrarily high resolution
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* images for printing.
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*
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* In every case, there are at least cases where you would want to do this
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* without actually rendering to a visible window.
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*
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*/
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#include <stdio.h>
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#include <GL/freeglut.h>
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#define OFFSCREEN_W 500
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#define OFFSCREEN_H 250
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int offscreen_id;
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int onscreen_id;
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const char *save_file_name = "offscreen.pnm";
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void cb_onscreen_display( void )
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{
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glClear( GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT );
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glColor3d( 1.0, 0.0, 0.0 );
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glBegin( GL_LINE_LOOP );
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glVertex2d( 0.0, 0.0 );
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glVertex2d( 0.5, 0.0 );
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glVertex2d( 0.5, 0.5 );
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glVertex2d( 0.0, 0.5 );
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glVertex2d( 0.0, 0.0 );
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glEnd( );
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glColor3d( 1.0, 1.0, 1.0 );
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glRasterPos2d( -1.0, 0.8 );
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glutBitmapString(
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GLUT_BITMAP_TIMES_ROMAN_24, "Press `s' or `S' to Send to"
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);
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glRasterPos2d( -.8, 0.6 );
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glutBitmapString(
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GLUT_BITMAP_TIMES_ROMAN_24, "'offscreen.pnm'"
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);
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glRasterPos2d( -1.0, 0.3 );
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glutBitmapString(
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GLUT_BITMAP_TIMES_ROMAN_24, "Press `q', `Q', or Esc to quit."
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);
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glutSwapBuffers( );
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}
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void write_raw_pnm( char *fname, char *pixels, int w, int h)
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{
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FILE *f;
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printf( "Trying to create: %s\n", fname );
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f = fopen( fname, "wb" );
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if( !f )
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printf( "Ouch! Cannot create file.\n" );
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else
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{
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int row;
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printf( "Opened file.\n" );
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fprintf( f, "P6\n" );
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fprintf( f, "# CREATOR: offscreen freeglut demo\n" );
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fprintf( f, "%d %d\n", w, h );
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fprintf( f, "255\n" );
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/*
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* Write the rows in reverse order because OpenGL's 0th row
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* is at the bottom.
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*/
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for( row = h; row; --row )
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fwrite( pixels + ((row - 1)*w*3), 1, 3 * w, f );
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fclose( f );
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}
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}
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void cb_offscreen_display( void )
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{
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static char pixels [OFFSCREEN_W * OFFSCREEN_H * 3];
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int i;
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cb_onscreen_display( );
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glColor3d( 0.0, 1.0, 0.0 );
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glBegin( GL_LINES );
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for( i = 0; i < 100; ++i)
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{
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glVertex2d( +1 - (i/50.0), +1 );
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glVertex2d( -1 + (i/50.0), -1 );
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}
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glEnd( );
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glFinish( );
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glPixelStorei( GL_PACK_ALIGNMENT, 1 );
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glReadPixels(
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0, 0, OFFSCREEN_W, OFFSCREEN_H,
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GL_RGB, GL_UNSIGNED_BYTE, (GLvoid *)pixels
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);
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write_raw_pnm( save_file_name, pixels, OFFSCREEN_W, OFFSCREEN_H );
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}
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void cb_onscreen_keyboard( unsigned char key, int x, int y )
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{
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switch( key )
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{
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case 's':
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case 'S':
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glutSetWindow( offscreen_id );
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glutPostRedisplay( );
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break;
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case '\x1b':
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case 'q':
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case 'Q':
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exit( 0 );
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break;
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default:
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break;
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}
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}
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int main( int argc, char **argv )
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{
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glutInit( &argc, argv );
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if( argv[ 1 ] )
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save_file_name = argv[ 1 ];
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glutInitDisplayMode( GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE );
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onscreen_id = glutCreateWindow( "Offscreen demo" );
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glutDisplayFunc( cb_onscreen_display );
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glutKeyboardFunc( cb_onscreen_keyboard );
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glutInitDisplayMode( GLUT_RGB | GLUT_SINGLE | GLUT_OFFSCREEN );
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glutInitWindowSize( OFFSCREEN_W, OFFSCREEN_H );
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offscreen_id = glutCreateWindow( "" );
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glutDisplayFunc( cb_offscreen_display );
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glutMainLoop( );
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}
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