C++ - SDL not working

Question

I've tried to follow this tutorial on the basics of displaying an image with SDL. But, when I run the program, it returns a blank screen. The image is in the correct directories, but it doesn't display in the program. Am I doing something wrong? I'd really like SDL to work.

EDIT

Here is my code:

#include <SDL/SDL.h> using namespace std; int main(int argc, char *argv[]) { SDL_Surface *hello; SDL_Surface *screen; SDL_Init(SDL_INIT_EVERYTHING); screen = SDL_SetVideoMode(640, 480, 32, SDL_SWSURFACE); hello = SDL_LoadBMP("hello.bmp"); SDL_BlitSurface(hello, NULL, screen, NULL); SDL_Flip(screen); SDL_Delay(2000); SDL_FreeSurface(hello); SDL_Quit(); return 0; }

I don't know if you are doing anything wrong as you haven't posted any code — Yacoby
– Yacoby, Commented Jun 8, 2010 at 16:36
Not sure if this is relevant, but the tutorial states that "Some Linux users will run and get a blank screen. Try running the program from the command line." — Steve S
– Steve S, Commented Jun 8, 2010 at 17:19
For what it's worth, this exact code works correctly on my system (an old version of Ubuntu). — Steve S
– Steve S, Commented Jun 8, 2010 at 17:19

gabriev82 · Accepted Answer · 2010-06-08 17:34:04Z

2

Use SDL_GetError() to find out why SDL_LoadBMP() fails loading your bitmap.
Read this thread too

answered Jun 8, 2010 at 17:34

gabriev82

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4 Comments

Greg Treleaven Over a year ago

Thanks, the error it returned was SDL_UpperBlit: passed a NULL surface. What does that mean?

gabriev82 Over a year ago

Strange... SDL version and OS?

Greg Treleaven Over a year ago

SDL 1.2, Windows Vista Home Premium x86. Is the tutorial maybe for a different version?

Masse Over a year ago

You could try checking with gdb how the surface is formed, does it have correct image data?

Greg Treleaven · Accepted Answer · 2010-08-30 20:17:46Z

I thought I said I had fixed this months ago, seems as though I had not. I recompiled it again and it worked, very strange.

user3526368 · Accepted Answer · 2014-04-12 13:10:35Z

1

Instead of SDL_Flip(screen) try using SDL_UpdateRect(screen,0,0,0,0)

answered Apr 12, 2014 at 13:10

user3526368

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Comments

Igor Krivokon · Accepted Answer · 2010-06-08 18:41:47Z

0

Make sure that hello.bmp is in your current directory, and that it's a readable and valid BMP file.

answered Jun 8, 2010 at 18:41

Igor Krivokon

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3 Comments

Greg Treleaven Over a year ago

Is there a certain format it can only take for the BMP, like 16-bit?

Igor Krivokon Over a year ago

It should support any windows BMP files; if you can see the BMP using a standard Windows viewer, it's good enough. Are you sure you are running the process in the same directory where your hello.bmp is stored? Do you use command line to run your program?

Greg Treleaven Over a year ago

It is in the same directory, and I have tried using the command line and the viewer. Is there any other explanation?

user1960346 · Accepted Answer · 2013-01-09 23:00:16Z

In the line: "hello = SDL_LoadBMP("hello.bmp");" , try "/hello.bmp" instead of "hello.bmp". I had the same problem but it seems that putting the slash ("/") before the file name helps in find and therefore, render the image, even if it isn't on the same directory as the program.

If you are on Windows the instead of "/hello.bmp", write "c://hello.bmp". The first one was for Mac. (:

EDIT: Forget it, I just realized it actually doesn't work, it worked for me since I had the file on my disk directory.

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