Hi,
I have searched with google specifically inside
the www.libsdl.org and I haven’t found anything.
Consider the following code of lesson01 ported to
Linux/SDL of nehe.gamedev.net:
#include <stdio.h>
#include <stdlib.h>
#include <GL/gl.h>
#include <GL/glu.h>
#include “SDL.h”
/* screen width, height, and bit depth */
#define SCREEN_WIDTH 1024
#define SCREEN_HEIGHT 768
#define SCREEN_BPP 32
/* Setup our booleans */
#define TRUE 1
#define FALSE 0
/* This is our SDL surface */
SDL_Surface *surface;
/* function to release/destroy our resources and restoring the old desktop /
void Quit( int returnCode )
{
/ clean up the window */
SDL_Quit( );
/* and exit appropriately */
exit( returnCode );
}
/* function to reset our viewport after a window resize /
int resizeWindow( int width, int height )
{
/ Height / width ration */
GLfloat ratio;
/* Protect against a divide by zero */
if ( height == 0 )
height = 1;
ratio = ( GLfloat )width / ( GLfloat )height;
/* Setup our viewport. */
glViewport( 0, 0, ( GLint )width, ( GLint )height );
/* change to the projection matrix and set our viewing volume. */
glMatrixMode( GL_PROJECTION );
glLoadIdentity( );
/* Set our perspective */
gluPerspective( 45.0f, ratio, 0.1f, 100.0f );
/* Make sure we're chaning the model view and not the projection */
glMatrixMode( GL_MODELVIEW );
/* Reset The View */
glLoadIdentity( );
return( TRUE );
}
/* function to handle key press events */
void handleKeyPress( SDL_keysym keysym )
{
switch ( keysym->sym )
{
case SDLK_ESCAPE:
/ ESC key was pressed /
Quit( 0 );
break;
case SDLK_F1:
/ F1 key was pressed
* this toggles fullscreen mode
*/
SDL_WM_ToggleFullScreen( surface );
break;
default:
break;
}
return;
}
/* general OpenGL initialization function */
int initGL( GLvoid )
{
/* Enable smooth shading */
glShadeModel( GL_SMOOTH );
/* Set the background black */
glClearColor( 0.0f, 0.0f, 0.0f, 0.0f );
/* Depth buffer setup */
glClearDepth( 1.0f );
/* Enables Depth Testing */
glEnable( GL_DEPTH_TEST );
/* The Type Of Depth Test To Do */
glDepthFunc( GL_LEQUAL );
/* Really Nice Perspective Calculations */
glHint( GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST );
return( TRUE );
}
/* Here goes our drawing code /
int drawGLScene( GLvoid )
{
/ These are to calculate our fps */
static GLint T0 = 0;
static GLint Frames = 0;
/* Clear The Screen And The Depth Buffer */
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
glLoadIdentity( );
/* Draw it to the screen */
SDL_GL_SwapBuffers( );
/* Gather our frames per second */
Frames++;
{
GLint t = SDL_GetTicks();
if (t - T0 >= 5000) {
GLfloat seconds = (t - T0) / 1000.0;
GLfloat fps = Frames / seconds;
printf("%d frames in %g seconds = %g FPS\n", Frames, seconds,
fps);
T0 = t;
Frames = 0;
}
}
return( TRUE );
}
int main( int argc, char *argv )
{
/ Flags to pass to SDL_SetVideoMode /
int videoFlags;
/ main loop variable /
int done = FALSE;
/ used to collect events /
SDL_Event event;
/ this holds some info about our display */
const SDL_VideoInfo videoInfo;
/ whether or not the window is active */
int isActive = TRUE;
/* initialize SDL */
if ( SDL_Init( SDL_INIT_VIDEO ) < 0 )
{
fprintf( stderr, "Video initialization failed: %s\n",
SDL_GetError( ) );
Quit( 1 );
}
/* Fetch the video info */
videoInfo = SDL_GetVideoInfo( );
if ( !videoInfo )
{
fprintf( stderr, "Video query failed: %s\n",
SDL_GetError( ) );
Quit( 1 );
}
/* the flags to pass to SDL_SetVideoMode */
videoFlags = SDL_OPENGL; /* Enable OpenGL in SDL */
videoFlags |= SDL_GL_DOUBLEBUFFER; /* Enable double buffering */
videoFlags |= SDL_HWPALETTE; /* Store the palette in hardware */
videoFlags |= SDL_RESIZABLE; /*Enable window resizing */
/* This checks to see if surfaces can be stored in memory */
if ( videoInfo->hw_available )
videoFlags |= SDL_HWSURFACE;
else
videoFlags |= SDL_SWSURFACE;
/* This checks if hardware blits can be done */
if ( videoInfo->blit_hw )
videoFlags |= SDL_HWACCEL;
/* Sets up OpenGL double buffering */
SDL_GL_SetAttribute( SDL_GL_DOUBLEBUFFER, 1 );
/* get a SDL surface */
surface = SDL_SetVideoMode( SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_BPP,
videoFlags );
/* Verify there is a surface */
if ( !surface )
{
fprintf( stderr, "Video mode set failed: %s\n",
SDL_GetError( ) );
Quit( 1 );
}
/* initialize OpenGL */
if ( initGL( ) == FALSE )
{
fprintf( stderr, "Could not initialize OpenGL.\n" );
Quit( 1 );
}
/* Resize the initial window */
resizeWindow( SCREEN_WIDTH, SCREEN_HEIGHT );
/* wait for events */
while ( !done )
{
/* handle the events in the queue */
while ( SDL_PollEvent( &event ) )
{
switch( event.type )
{
case SDL_ACTIVEEVENT:
/* Something's happend with our focus
* If we lost focus or we are iconified, we
* shouldn't draw the screen
*/
if ( event.active.gain == 0 )
isActive = FALSE;
else
isActive = TRUE;
break;
case SDL_VIDEORESIZE:
/* handle resize event */
surface = SDL_SetVideoMode( event.resize.w,
event.resize.h,
16, videoFlags );
if ( !surface )
{
fprintf( stderr, "Could not get a surface
after resize: %s\n", SDL_GetError( ) );
Quit( 1 );
}
resizeWindow( event.resize.w, event.resize.h );
break;
case SDL_KEYDOWN:
/* handle key presses /
handleKeyPress( &event.key.keysym );
break;
case SDL_QUIT:
/ handle quit requests */
done = TRUE;
break;
default:
break;
}
}
/* draw the scene */
if ( isActive )
drawGLScene( );
}
/* clean ourselves up and exit */
Quit( 0 );
/* Should never get here */
return( 0 );
}
If you switch to fullscreen with the F1 key you get
the crash, if you switch to 800x600 at the beginning
of the file no crash occur. Is it a bug or what else ?
Thank for the attention,–
Giuseppe Torelli