C ++和SDL：显示图像有问题吗？

Question

For some reason SDL refuses to render an image. I don't see why and it's really bogging down my progress on a 2d game i'm developing. Everything is linked properly and such. Here's my code:

//main.cpp
#include "main.h"

void game::createWindow(const int SCREEN_W, const int SCREEN_H, const char* SCREEN_NAME)
{
 buffer = SDL_SetVideoMode(SCREEN_W, SCREEN_H, 0, NULL);
 SDL_WM_SetCaption(SCREEN_NAME, NULL);
}

void game::enterLoop()
{
 while(Running == true)
 {
  SDL_BlitSurface(zombie, NULL, buffer, NULL);
  SDL_Flip(buffer);

  while(SDL_PollEvent(&gameEvent))
  {
   if(gameEvent.type == SDL_QUIT)
   {
    Running = false;
   }
  }
 }
}

void game::loadContent()
{
 zombie = SDL_LoadBMP("zombie.bmp");
}

int main(int argc, char* argv[])
{
 game gameObj;

 SDL_Init(SDL_INIT_EVERYTHING);
 gameObj.createWindow(960, 600, "uShootZombies");
 gameObj.loadContent();
 gameObj.enterLoop();

 SDL_Quit();

 return 0;
}

//main.h
#include <SDL.h>
#include <fstream>
#include <string>

using namespace std;

class game
{
 public:
 void createWindow(const int SCREEN_W, const int SCREEN_H, const char* SCREEN_NAME);
 void enterLoop();
 void loadContent();

 game()
 {
  Running = true;
 }

 ~game()
 {
  SDL_FreeSurface(buffer);

  SDL_FreeSurface(background);
  SDL_FreeSurface(player);
  SDL_FreeSurface(zombie);
 }

 private:
 SDL_Surface* buffer;

 SDL_Surface* background;
 SDL_Surface* player;
 SDL_Surface* zombie;

 SDL_Event gameEvent;
 bool Running;
};NU

Answer 1

I just copied all of your code to use in code::blocks and it works fine. Of course I was using my own .bmp file which I named "zombie.bmp"

Are you sure your .bmp file is ok?

Be aware that if you originally save it as a .jpeg file or something like that, then simply renamed it to .bmp, it won't work (And it won't throw an error either)

It must be originally saved as a bmp.

That is all I can think of.

Answer 2

It seems that Sour Lemon has already solved your problem, but I still thought it would be worth pointing out that the above code doesn't perform any checks to make sure that your zombie image was actually loaded correctly.

You should be doing something like this:

void game::loadContent()
{
    zombie = SDL_LoadBMP("zombie.bmp");
    if (zombie == NULL) {
        ReportError(SDL_GetError());
    }
}