SDL_RenderClear(g_ren);
SDL_Texture *tex_bk = SDL_CreateTextureFromSurface(g_ren, bk);
SDL_Texture *tex_des = SDL_CreateTextureFromSurface(g_ren, widget);
SDL_RenderCopy(g_ren, tex_bk, NULL, NULL);
SDL_SetTextureBlendMode(tex_des,blendMode);
SDL_SetRenderDrawBlendMode(g_ren,blendMode);
SDL_RenderCopy(g_ren, tex_des, NULL, NULL);
SDL_RenderPresent(g_ren);
SDL_DestroyTexture(tex_des);
SDL_DestroyTexture(tex_bk);
我想使用SDL_RenderCopy复制tex_bk,并在第二次使用SDL_RenderCopy混合tex_des。但应用程序总是显示tex_des图像,而tex_bk图像总是消失。