Tile the background with SDL2 and display the foreground

Environment: SDL2 + vc++2015

The following code will open Background.bmp and image.bmp, tile the background background, and render the image as a foreground

1#include <iostream>2#include"SDL.h"3 4 //Screen Width5 Const intScreen_width =640;6 Const intScreen_height =480;7 8 //Global window and renderer9Sdl_window *window =nullptr;TenSdl_renderer *renderer =nullptr; One  A //Loading Pictures -sdl_texture* LoadImage (std::stringfile) - { theSdl_surface *loadedimage =nullptr; -Sdl_texture *texture =nullptr; -  -Loadedimage =sdl_loadbmp (File.c_str ()); +     if(Loadedimage! =nullptr) -     { +Texture =sdl_createtexturefromsurface (renderer, loadedimage); A Sdl_freesurface (loadedimage); at     } -     Else -Std::cout << sdl_geterror () <<Std::endl; -     returnTexture; - } -  in //apply a surface to the renderer - voidApplysurface (intXintY, sdl_texture *tex, Sdl_renderer *rend) to { + Sdl_rect Pos; -Pos.x =x; thePos.y =y; *Sdl_querytexture (tex, NULL, NULL, &AMP;POS.W, &pos.h); $Sdl_rendercopy (Rend, Tex, NULL, &POS);Panax Notoginseng } -  the intMainintargcChar**argv) + { A     //Initialize SDL the     if(Sdl_init (sdl_init_everything) = =-1) +     { -Std::cout << sdl_geterror () <<Std::endl; $         return 1; $     } -  -     //Create Window thewindow = Sdl_createwindow ("Lesson 2", - sdl_windowpos_centered, sdl_windowpos_centered,Wuyi screen_width, Screen_height, sdl_window_shown); the     if(Window = =nullptr) -     { WuStd::cout << sdl_geterror () <<Std::endl; -         return 2; About     } $  -     //Create renderer -Renderer = sdl_createrenderer (window,-1, -sdl_renderer_accelerated |sdl_renderer_presentvsync); A     if(Renderer = =nullptr) +     { theStd::cout << sdl_geterror () <<Std::endl; -         return 3; $     } the  the     //create background and foreground textures theSdl_texture *background = nullptr, *image =nullptr; theBackground = LoadImage ("background.bmp"); -Image = LoadImage ("image.bmp"); in     if(Background = = Nullptr | | image = =nullptr) the         return 4; the  About     //Empty renderer the sdl_renderclear (renderer); the  the     //internal flush the background in the renderer +     intBW, BH; -Sdl_querytexture (background, NULL, NULL, &AMP;BW, &BH); theApplysurface (0,0, background, renderer);BayiApplysurface (BW,0, background, renderer); theApplysurface (0, BH, background, renderer); the applysurface (BW, BH, background, renderer); -  -     //placing the foreground in the center of the renderer the     intIW, IH; theSdl_querytexture (image, NULL, NULL, &AMP;IW, &IH); the     intx = screen_width/2-IW/2; the     inty = screen_height/2-IH/2; - applysurface (x, y, image, renderer); the  the     //Render Renderer the sdl_renderpresent (renderer);94Sdl_delay ( -); the  the     //Freeing Resources the sdl_destroytexture (background);98 sdl_destroytexture (image); About sdl_destroyrenderer (renderer); - Sdl_destroywindow (window);101 102 sdl_quit ();103 104     return 0; the}

Eggs:

What if the window becomes 1920*1080? The tiling method above is not flexible enough. Try the following:

1     int BW, BH; 2     Sdl_querytexture (background, NULL, NULL, &BW, &BH); 3      for (int0; y <= screen_height; y + = BH) 4          for (int0; x <= screen_width; x + = BW) 5             Applysurface (x, y, background, renderer);

Tile the background with SDL2 and display the foreground