奇怪的基本SDL
Weird basic SDL
本文关键字:SDL 更新时间:2023-10-16
我刚开始学习SDL,我发现如果我初始化一个SDL_Rect变量,SDL_Delay不起作用。然后,如果我在SDL_Rect中设置了一个值,图像甚至不显示(或暂停)。我不明白。我从lazyfoo的教程中得到了这段代码,我现在只是在摆弄它
#include <SDL/SDL.h>
#include <iostream>
using namespace std;
int main( int argc, char* args[] ){
int width = 512;
int height = 512;
//The images
SDL_Surface* source = NULL;
SDL_Surface* screen = NULL;
//Start SDL
//SDL_Init( SDL_INIT_EVERYTHING );
if( SDL_Init( SDL_INIT_EVERYTHING ) == -1 ) {
return 1;
}
//Set up screen
screen = SDL_SetVideoMode( width, height, 24, SDL_SWSURFACE );
//Load imagec
source = SDL_LoadBMP( "image.bmp");
//Apply image to screen
SDL_Rect * hello; //here is where it messes up the program
//for(int a = 0; a < width; a++){ // i was trying to make the image move around the screen/window
//hello -> x = 0;
//now -> w = 200;
//now -> h = 200;
//for(int b = 0; b < height; b++){
//now -> y = 0;
//SDL_WM_SetCaption( "ajsncnsc", NULL );
SDL_BlitSurface( source, NULL, screen, NULL );
//Update Screen
SDL_Flip( screen );
SDL_Delay( 2000 );
// }
//}
//Free the loaded image
SDL_FreeSurface( source );
//Quit SDL
SDL_Quit();
return 0;
}
SDL_Rect * hello;
创建一个指向SDL_Rect
的指针。它指向随机内存,因为您没有为它分配任何内存。修改它的成员可以导致任何事情发生。
使用SDL_Rect hello;
代替-这创建了一个实际的SDL_Rect
,你现在可以安全地做例如hello.x = 200;
不修改内存你不拥有。
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