我正在使用IMG_Load()加载png文件,但它根本无法正常工作。 loadedImage = IMG_Load(filename.c_str());在这句话之后,loadedImage仍为NULL,没有发生错误。 PS:我使用的是VS C ++ 2008,png文件位于develop文件夹中。这是我的代码:(这正是Lazy Foo喜欢的)
//The headers
#include "SDL.h"
#include "SDL_image.h"
#include <string>
#pragma comment( linker, "/subsystem:\"windows\" /entry:\"mainCRTStartup\"" )
//Screen attributes
const int SCREEN_WIDTH = 640;
const int SCREEN_HEIGHT = 480;
const int SCREEN_BPP = 32;
//The surfaces
SDL_Surface *image = NULL;
SDL_Surface *screen = NULL;
SDL_Surface *load_image( std::string filename )
{
//The image that's loaded
SDL_Surface* loadedImage = NULL;
//The optimized image that will be used
SDL_Surface* optimizedImage = NULL;
//Load the image using SDL_image
loadedImage = IMG_Load(filename.c_str());
//If the image loaded
if( loadedImage != NULL )
{
//Create an optimized image
//cout<<"Flag";
optimizedImage = SDL_DisplayFormat( loadedImage );
//Free the old image
SDL_FreeSurface( loadedImage );
}
//Return the optimized image
return optimizedImage;
}
void apply_surface( int x, int y, SDL_Surface* source, SDL_Surface* destination )
{
//Rectangle to hold the offsets
SDL_Rect offset;
//Get offsets
offset.x = x;
offset.y = y;
//Blit the surface
SDL_BlitSurface( source, NULL, destination, &offset );
}
bool init()
{
//Initialize all SDL subsystems
if( SDL_Init( SDL_INIT_EVERYTHING ) == -1 )
{
return false;
}
//Set up the screen
screen = SDL_SetVideoMode( SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_BPP, SDL_SWSURFACE );
//If there was an error in setting up the screen
if( screen == NULL )
{
return false;
}
//Set the window caption
SDL_WM_SetCaption( "PNG test", NULL );
//If everything initialized fine
return true;
}
void clean_up()
{
//Free the surface
SDL_FreeSurface( image );
//Quit SDL
SDL_Quit();
}
int main( int argc, char* args[] )
{
//Initialize
if( init() == false )
{
return 1;
}
//Load the image
image = load_image( "look.png" );
//If there was a problem in loading the image
if( image == NULL )
{
return 5;
}
//Apply the surface to the screen
apply_surface( 0, 0, image, screen );
//Update the screen
if( SDL_Flip( screen ) == -1 )
{
return 1;
}
//Wait 2 seconds
SDL_Delay( 2000 );
//Free the surface and quit SDL
clean_up();
return 0;
}
输出返回5.
答案 0 :(得分:8)
我的坏。 我只是将SDL_image.dll复制到exe floder。 我还应该复制zlib1.dll和libpng12-0.dll 实际上,所有的dll都是需要的,因为如果没有这样的dll,程序就不会给出任何错误提示,这是令人困惑的。
答案 1 :(得分:1)
如果从网站下载libpng,你会发现一个名为libpng12.dll的文件。将该文件复制到system32不起作用,因为SDL_image实际上查找名为“libpng12-0.dll”的文件。我在代码中实现了IMG_GetError()方法后发现了这一点。错误消息非常清楚地说明了......
所以你要做的就是将libpng12.dll复制到system32并将其重命名为libpng12-0.dll!一切正常。