我正在尝试使用颜色键控来实现SDL的透明度。虽然它适用于BMP文件,但它不适用于PNG文件。
这是我的代码:
#include <SDL/SDL.h>
#include <SDL/SDL_image.h>
int main(int argc, char *argv[])
{
SDL_Init(SDL_INIT_EVERYTHING);
SDL_Surface *displaySurface = SDL_SetVideoMode(200, 100, 32, SDL_HWSURFACE | SDL_DOUBLEBUF);
SDL_Surface *tmpSurface = NULL;
SDL_Surface *backgroundSurface = NULL;
SDL_Surface *bmpSurface = NULL;
SDL_Surface *pngSurface = NULL;
tmpSurface = IMG_Load("background.png");
backgroundSurface = SDL_DisplayFormat(tmpSurface);
SDL_FreeSurface(tmpSurface);
tmpSurface = SDL_LoadBMP("bmpImage.bmp");
bmpSurface = SDL_DisplayFormat(tmpSurface);
SDL_FreeSurface(tmpSurface);
SDL_SetColorKey(bmpSurface, SDL_SRCCOLORKEY | SDL_RLEACCEL, SDL_MapRGB(bmpSurface->format, 255, 0, 255));
tmpSurface = IMG_Load("pngImage.png");
pngSurface = SDL_DisplayFormat(tmpSurface);
SDL_FreeSurface(tmpSurface);
SDL_SetColorKey(pngSurface, SDL_SRCCOLORKEY | SDL_RLEACCEL, SDL_MapRGB(pngSurface->format, 255, 0, 255));
SDL_Rect dest;
dest.x = 0;
dest.y = 0;
SDL_BlitSurface(backgroundSurface, NULL, displaySurface, &dest);
SDL_BlitSurface(bmpSurface, NULL, displaySurface, &dest);
dest.x = 50;
SDL_BlitSurface(pngSurface, NULL, displaySurface, &dest);
SDL_Flip(displaySurface);
SDL_Event event;
while (1) {
while (SDL_PollEvent(&event)) {
;
}
SDL_Delay(1);
}
return 0;
}
我上传了我在这里使用的代码和图片:
http://tobias.braun-abstatt.de/files/forums/transparency_test.zip
答案 0 :(得分:1)
如果您使用的是SDL_image版本1.2.10或1.2.11,请务必将其更新至版本1.2.12。
#include <SDL/SDL_image.h>
#if (SDL_IMAGE_MAJOR_VERSION != 1) || (SDL_IMAGE_MINOR_VERSION != 2) || (SDL_IMAGE_PATCHLEVEL < 12)
#error "Invalid SDL_image version"
#endif