[英]SDL Linker Errors
以下代码非常简单。 它只是使用SDL以背景将图像绘制到屏幕上。 我之前能够运行的程序运行良好,引用一切没有问题。
然而,现在,编译器抱怨。
无论如何,这是代码:
#include <iostream>
#include <string>
#include "SDL/SDL.h"
const int SCREEN_WIDTH = 640;
const int SCREEN_HEIGHT = 480;
const int SCREEN_BPP = 32;
using std::string;
SDL_Surface * load_image(std::string filename)
{
SDL_Surface * loadedImage = NULL;
SDL_Surface * optimizedImage = NULL;
loadedImage = SDL_LoadBMP(filename.c_str());
if (loadedImage != NULL)
{
optimizedImage = SDL_DisplayFormat(loadedImage);
SDL_FreeSurface(loadedImage);
}
return optimizedImage;
}
void apply_surface(int x, int y, SDL_Surface * source, SDL_Surface * destination)
{
SDL_Rect offset;
//Give offsets to the rectangle
offset.x = x;
offset.y = y;
SDL_BlitSurface(source, NULL, destination, &offset);
}
int main(int argc, char * args[])
{
if ( SDL_Init(SDL_INIT_EVERYTHING) == -1 )
{
return 1;
}
else
{
SDL_Surface * screen = SDL_SetVideoMode(SCREEN_WIDTH,
SCREEN_HEIGHT,
SCREEN_BPP,
SDL_SWSURFACE);
if (screen == NULL)
{
return 1;
}
else
{
SDL_WM_SetCaption("Hello World", NULL);
SDL_Surface * message = load_image("hello.bmp");
SDL_Surface * background = load_image("background.bmp");
apply_surface(0, 0, background, screen);
apply_surface(320, 0, background, screen);
apply_surface(0, 240, background, screen);
apply_surface(320, 240, background, screen);
if (SDL_Flip( screen ) == -1)
{
return 1;
}
}
}
return 0;
}
我的输出:
holland@holland-litevision:~/code/cpp$ g++ main.o
main.o: In function `load_image(std::basic_string<char, std::char_traits<char>, std::allocator<char> >)':
main.cpp:(.text+0x2b): undefined reference to `SDL_RWFromFile'
main.cpp:(.text+0x3b): undefined reference to `SDL_LoadBMP_RW'
main.cpp:(.text+0x4f): undefined reference to `SDL_DisplayFormat'
main.cpp:(.text+0x5d): undefined reference to `SDL_FreeSurface'
main.o: In function `apply_surface(int, int, SDL_Surface*, SDL_Surface*)':
main.cpp:(.text+0x97): undefined reference to `SDL_UpperBlit'
main.o: In function `main':
main.cpp:(.text+0xaf): undefined reference to `SDL_Init'
main.cpp:(.text+0xe7): undefined reference to `SDL_SetVideoMode'
main.cpp:(.text+0x110): undefined reference to `SDL_WM_SetCaption'
main.cpp:(.text+0x24c): undefined reference to `SDL_Flip'
collect2: ld returned 1 exit status
您没有在SDL库中进行链接。 试试这个:
g++ main.o `sdl-config --libs`
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