Quote:Original post by jimi_hendrixThe only way I can see that IMG_Load can fail (Except for a bug in sdl_image) is if filename is invalid. What happens if you printf() / cout filename.c_str() ?
segfaults on IMG_Load()
Why is this segfaulting???
Is IMG_Load() a macro or a function (I personally ever only used SDL_LoadBitmap(), afair)?
If a function, can you give us the output of?
If a function, can you give us the output of
cout << reinterpret_cast <void*> (IMG_Load) << endl;
Author
ok the previous code was so full of bugs and it was so messed up i started over...but i got another segfault :)
how would i read this backtrace to find out what line its on (im not good at looking at stuff like this)
(gdb) bt
#0 0x00007fb75915b5cb in SDL_DisplayFormat () from /usr/lib/libSDL-1.2.so.0
#1 0x0000000000400fd0 in loadImage (filename=
{static npos = 18446744073709551615, _M_dataplus = {<std::allocator<char>> = {<__gnu_cxx::new_allocator<char>> = {<No data fields>}, <No data fields>}, _M_p = 0x7fff615dfa60 "(\020�"}}, Red=255, Green=255, Blue=255)
at shooter.cpp:292
#2 0x00000000004012fa in Player (this=0x7fff615dfac0) at shooter.cpp:96
#3 0x0000000000401383 in Game (this=0x7fff615dfac0) at shooter.cpp:121
#4 0x000000000040108a in main (argc=1, args=0x7fff615dfbe8) at shooter.cpp:328
once i get past this little segfault ill be back where i was with cleaner code
heres the source
how would i read this backtrace to find out what line its on (im not good at looking at stuff like this)
(gdb) bt
#0 0x00007fb75915b5cb in SDL_DisplayFormat () from /usr/lib/libSDL-1.2.so.0
#1 0x0000000000400fd0 in loadImage (filename=
{static npos = 18446744073709551615, _M_dataplus = {<std::allocator<char>> = {<__gnu_cxx::new_allocator<char>> = {<No data fields>}, <No data fields>}, _M_p = 0x7fff615dfa60 "(\020�"}}, Red=255, Green=255, Blue=255)
at shooter.cpp:292
#2 0x00000000004012fa in Player (this=0x7fff615dfac0) at shooter.cpp:96
#3 0x0000000000401383 in Game (this=0x7fff615dfac0) at shooter.cpp:121
#4 0x000000000040108a in main (argc=1, args=0x7fff615dfbe8) at shooter.cpp:328
once i get past this little segfault ill be back where i was with cleaner code
heres the source
#include "SDL/SDL.h"#include <string>#include "SDL/SDL_image.h"#include "assert.h"//The attributes of the screen const int SCREEN_WIDTH = 640; const int SCREEN_HEIGHT = 480; const int SCREEN_BPP = 32; const int FRAMES_PER_SECOND = 30;SDL_Surface* screen = NULL;//prototypesSDL_Surface* loadImage(std::string filename, int Red, int Blue, int Green);void applySurface( int x, int y, SDL_Surface* source, SDL_Surface* destination );//classesclass Timer{ private: //The clock time when the timer started int startTicks; //The ticks stored when the timer was paused int pausedTicks; //The timer status bool paused; bool started; public: //Initializes variables Timer(); //The various clock actions void start(); void stop(); void pause(); void unpause(); //Gets the timer's time int get_ticks(); //Checks the status of the timer bool is_started(); bool is_paused(); };class Bullet{ public: int x, y, velY; SDL_Surface* image; Bullet() { velY = 15; image = loadImage("bullet.bmp", 0, 0, 0); } void fire(int X, int Y) { x = X; y = Y; applySurface(x, y, image, screen); } void update() { if (y >= 0) { y += velY; applySurface(x, y, image, screen); } }};class Ship{};class Player{ public: int x, y, velX; SDL_Surface* ship; Player() { x = SCREEN_WIDTH / 2; y = SCREEN_HEIGHT - 70; velX = 5; ship = loadImage("player.bmp", 255, 255, 255); } void handleInput() { Uint8 *keystates = SDL_GetKeyState( NULL ); if (keystates[SDLK_LEFT]) { if (x > 0) { x -= velX; } } if (keystates[SDLK_RIGHT]) { if (x < SCREEN_WIDTH) { x += velX; } } }};class Game{ Player player; Timer fps; //SDL variables SDL_Surface* playerShip; SDL_Event event; public: void init() { //setup screen SDL_Init(SDL_INIT_EVERYTHING); screen = SDL_SetVideoMode( SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_BPP, SDL_SWSURFACE ); SDL_WM_SetCaption("Space Shooter", NULL); //load images and blit applySurface(SCREEN_WIDTH / 2, SCREEN_HEIGHT - 70, player.ship, screen); //enable repeats SDL_EnableKeyRepeat(1, 5); //flip the screen SDL_Flip(screen); } void loop() { bool quit = false; while (quit == false) { while (SDL_PollEvent(&event)) { if (event.type == SDL_QUIT) { quit = true; } player.handleInput(); SDL_FillRect( screen, &screen->clip_rect, SDL_MapRGB( screen->format, 0, 0, 0 ) ); applySurface(player.x, player.y, player.ship, screen); SDL_Flip(screen); //Cap the frame rate if( fps.get_ticks() < 1000 / FRAMES_PER_SECOND ) { SDL_Delay( ( 1000 / FRAMES_PER_SECOND ) - fps.get_ticks() ); } } } } void close() { SDL_FreeSurface(playerShip); SDL_FreeSurface(screen); }};//Timer methodsTimer::Timer(){ //Initialize the variables startTicks = 0; pausedTicks = 0; paused = false; started = false; }void Timer::start(){ //Start the timer started = true; //Unpause the timer paused = false; //Get the current clock time startTicks = SDL_GetTicks(); }void Timer::stop(){ //Stop the timer started = false; //Unpause the timer paused = false; }void Timer::pause(){ //If the timer is running and isn't already paused if( ( started == true ) && ( paused == false ) ) { //Pause the timer paused = true; //Calculate the paused ticks pausedTicks = SDL_GetTicks() - startTicks; }}void Timer::unpause(){ //If the timer is paused if( paused == true ) { //Unpause the timer paused = false; //Reset the starting ticks startTicks = SDL_GetTicks() - pausedTicks; //Reset the paused ticks pausedTicks = 0; }}int Timer::get_ticks(){ //If the timer is running if( started == true ) { //If the timer is paused if( paused == true ) { //Return the number of ticks when the timer was paused return pausedTicks; } else { //Return the current time minus the start time return SDL_GetTicks() - startTicks; } } //If the timer isn't running return 0; }bool Timer::is_started(){ return started; }bool Timer::is_paused(){ return paused; }//Game MethodsSDL_Surface* loadImage( std::string filename, int Red, int Green, int Blue ) { //The image that's loaded SDL_Surface* loadedImage = NULL; //The optimized image that will be used SDL_Surface* optimizedImage = NULL; //Load the image loadedImage = IMG_Load( filename.c_str() ); assert(loadedImage); //If the image loaded if( loadedImage != NULL ) { //Create an optimized image assert(loadedImage); optimizedImage = SDL_DisplayFormat( loadedImage ); //Free the old image SDL_FreeSurface( loadedImage ); //If the image was optimized just fine if( optimizedImage != NULL ) { //Map the color key Uint32 colorkey = SDL_MapRGB( optimizedImage->format, Red, Green, Blue ); //Set all pixels of color R 0, G 0xFF, B 0xFF to be transparent SDL_SetColorKey( optimizedImage, SDL_SRCCOLORKEY, colorkey ); } //Return the optimized image } return optimizedImage; }void applySurface( int x, int y, SDL_Surface* source, SDL_Surface* destination ) { //Make a temporary rectangle to hold the offsets SDL_Rect offset; //Give the offsets to the rectangle offset.x = x; offset.y = y; //Blit the surface SDL_BlitSurface( source, NULL, destination, &offset ); }int main(int argc, char* args[]){ Game game; game.init(); game.loop(); game.close(); return 0;}
While debugging, sometimes the working directory is not the directory that the program is in. I am not familiar with gdb, but you should find out what it defaults the working directory to. Then, make sure that the image is inside of that directory.
Though this really shouldn't be the problem since IMG_Load is supposed to just return null if it can't load the file. The only reason I can think of for segfaulting is if the file is corrupted. Nonetheless, check the above if you haven't already.
Though this really shouldn't be the problem since IMG_Load is supposed to just return null if it can't load the file. The only reason I can think of for segfaulting is if the file is corrupted. Nonetheless, check the above if you haven't already.
Quote:Original post by jimi_hendrix
_M_dataplus = {<std::allocator<char>> = {<__gnu_cxx::new_allocator<char>> = {<No data fields>}, <No data fields>}, _M_p = 0x7fff615dfa60 "(\020�"}}, Red=255, Green=255, Blue=255)
That's some weird garbage where there should be the filename.
Does anything change if you use:
SDL_Surface* loadImage(const std::string & filename, int Red, int Blue, int Green);SDL_Surface* loadImage(const char * filename, int Red, int Blue, int Green);
Author
now i get
g++ -Wall -g -ggdb -o test shooter.cpp -lSDL -lSDL_image
/tmp/ccyZweJU.o: In function `Player':
/home/vincent/programs/C++/shooter.cpp:96: undefined reference to `loadImage(std::basic_string<char, std::char_traits<char>, std::allocator<char> >, int, int, int)'
collect2: ld returned 1 exit status
make: *** [all] Error 1
when i sue char* filename...heres source
g++ -Wall -g -ggdb -o test shooter.cpp -lSDL -lSDL_image
/tmp/ccyZweJU.o: In function `Player':
/home/vincent/programs/C++/shooter.cpp:96: undefined reference to `loadImage(std::basic_string<char, std::char_traits<char>, std::allocator<char> >, int, int, int)'
collect2: ld returned 1 exit status
make: *** [all] Error 1
when i sue char* filename...heres source
#include "SDL/SDL.h"#include <string>#include "SDL/SDL_image.h"#include "assert.h"//The attributes of the screen const int SCREEN_WIDTH = 640; const int SCREEN_HEIGHT = 480; const int SCREEN_BPP = 32; const int FRAMES_PER_SECOND = 30;SDL_Surface* screen = NULL;//prototypesSDL_Surface* loadImage(std::string filename, int Red, int Blue, int Green);void applySurface( int x, int y, SDL_Surface* source, SDL_Surface* destination );//classesclass Timer{ private: //The clock time when the timer started int startTicks; //The ticks stored when the timer was paused int pausedTicks; //The timer status bool paused; bool started; public: //Initializes variables Timer(); //The various clock actions void start(); void stop(); void pause(); void unpause(); //Gets the timer's time int get_ticks(); //Checks the status of the timer bool is_started(); bool is_paused(); };class Bullet{ public: int x, y, velY; SDL_Surface* image; Bullet() { velY = 15; image = loadImage("bullet.bmp", 0, 0, 0); } void fire(int X, int Y) { x = X; y = Y; applySurface(x, y, image, screen); } void update() { if (y >= 0) { y += velY; applySurface(x, y, image, screen); } }};class Ship{};class Player{ public: int x, y, velX; SDL_Surface* ship; Player() { x = SCREEN_WIDTH / 2; y = SCREEN_HEIGHT - 70; velX = 5; ship = loadImage("player.bmp", 255, 255, 255); } void handleInput() { Uint8 *keystates = SDL_GetKeyState( NULL ); if (keystates[SDLK_LEFT]) { if (x > 0) { x -= velX; } } if (keystates[SDLK_RIGHT]) { if (x < SCREEN_WIDTH) { x += velX; } } }};class Game{ Player player; Timer fps; //SDL variables SDL_Surface* playerShip; SDL_Event event; public: void init() { //setup screen SDL_Init(SDL_INIT_EVERYTHING); screen = SDL_SetVideoMode( SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_BPP, SDL_SWSURFACE ); SDL_WM_SetCaption("Space Shooter", NULL); //load images and blit applySurface(SCREEN_WIDTH / 2, SCREEN_HEIGHT - 70, player.ship, screen); //enable repeats SDL_EnableKeyRepeat(1, 5); //flip the screen SDL_Flip(screen); } void loop() { bool quit = false; while (quit == false) { while (SDL_PollEvent(&event)) { if (event.type == SDL_QUIT) { quit = true; } player.handleInput(); SDL_FillRect( screen, &screen->clip_rect, SDL_MapRGB( screen->format, 0, 0, 0 ) ); applySurface(player.x, player.y, player.ship, screen); SDL_Flip(screen); //Cap the frame rate if( fps.get_ticks() < 1000 / FRAMES_PER_SECOND ) { SDL_Delay( ( 1000 / FRAMES_PER_SECOND ) - fps.get_ticks() ); } } } } void close() { SDL_FreeSurface(playerShip); SDL_FreeSurface(screen); }};//Timer methodsTimer::Timer(){ //Initialize the variables startTicks = 0; pausedTicks = 0; paused = false; started = false; }void Timer::start(){ //Start the timer started = true; //Unpause the timer paused = false; //Get the current clock time startTicks = SDL_GetTicks(); }void Timer::stop(){ //Stop the timer started = false; //Unpause the timer paused = false; }void Timer::pause(){ //If the timer is running and isn't already paused if( ( started == true ) && ( paused == false ) ) { //Pause the timer paused = true; //Calculate the paused ticks pausedTicks = SDL_GetTicks() - startTicks; }}void Timer::unpause(){ //If the timer is paused if( paused == true ) { //Unpause the timer paused = false; //Reset the starting ticks startTicks = SDL_GetTicks() - pausedTicks; //Reset the paused ticks pausedTicks = 0; }}int Timer::get_ticks(){ //If the timer is running if( started == true ) { //If the timer is paused if( paused == true ) { //Return the number of ticks when the timer was paused return pausedTicks; } else { //Return the current time minus the start time return SDL_GetTicks() - startTicks; } } //If the timer isn't running return 0; }bool Timer::is_started(){ return started; }bool Timer::is_paused(){ return paused; }//Game MethodsSDL_Surface* loadImage( char* filename, int Red, int Green, int Blue ) { //The image that's loaded SDL_Surface* loadedImage = NULL; //The optimized image that will be used SDL_Surface* optimizedImage = NULL; //Load the image loadedImage = IMG_Load( filename ); assert(loadedImage); //If the image loaded if( loadedImage != NULL ) { //Create an optimized image assert(loadedImage); optimizedImage = SDL_DisplayFormat( loadedImage ); //Free the old image SDL_FreeSurface( loadedImage ); //If the image was optimized just fine if( optimizedImage != NULL ) { //Map the color key Uint32 colorkey = SDL_MapRGB( optimizedImage->format, Red, Green, Blue ); //Set all pixels of color R 0, G 0xFF, B 0xFF to be transparent SDL_SetColorKey( optimizedImage, SDL_SRCCOLORKEY, colorkey ); } //Return the optimized image } return optimizedImage; }void applySurface( int x, int y, SDL_Surface* source, SDL_Surface* destination ) { //Make a temporary rectangle to hold the offsets SDL_Rect offset; //Give the offsets to the rectangle offset.x = x; offset.y = y; //Blit the surface SDL_BlitSurface( source, NULL, destination, &offset ); }int main(int argc, char* args[]){ Game game; game.init(); game.loop(); game.close(); return 0;}
Ahem.
The assert() after the IMG_Load() does nothing if IMG_Load() segv's. Also, make sure that at the point of #inclusion of assert NDEBUG isn't #defined.
Try out before the call to it.
Quote:
Is IMG_Load() a macro or a function (I personally ever only used SDL_LoadBitmap(), afair)?
If a function, can you give us the output of?cout << reinterpret_cast <void*> (IMG_Load) << endl;
The assert() after the IMG_Load() does nothing if IMG_Load() segv's. Also, make sure that at the point of #inclusion of assert NDEBUG isn't #defined.
Try out
assert (0 != reinterpret_cast <void*> (IMG_Load));
Author
no segfault but no image on screen either...all i did was change std::string to char* in the prototype and function
also i removed the .c_str() method in IMG_Load()...since there is no neeed for it with a char*
also i removed the .c_str() method in IMG_Load()...since there is no neeed for it with a char*
For the third time: Is IMG_Load != 0?
What I am trying to find out is that whether SDL did load the function properly or not. I may be in a big mistake here as I don't know the inner details of the SDL-Lib, but I am just trying to help someone here.
What I am trying to find out is that whether SDL did load the function properly or not. I may be in a big mistake here as I don't know the inner details of the SDL-Lib, but I am just trying to help someone here.
This topic is closed to new replies.
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