Sdl2 concise tutorial (4): using SDL_ Image library importing pictures

List of articles

SDL2 A concise tutorial （ One ）： Use Cmake and Conan structure SDL2 Programming environment

SDL2 A concise tutorial （ Two ）： Create an empty window

SDL2 A concise tutorial （ 3、 ... and ）： display picture

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Integrate SDL_IMAGE

stay SDL2 A concise tutorial （ 3、 ... and ）： display picture
in , We use SDL2 Self contained function SDL_LoadBMP() Import bmp picture . But this function can only import bmp Format ,SDL2 No other functions are provided to import pictures in other formats . Fortunately, , There's a man named sdl_image The library of can provide such functions . This article will show you how to use sdl_image Import pictures in other formats .

Integrate in our project sdl_image It's simple （ thank conan Convenience brought by ）, You just need to conanfile.txt Add a pair of sdl_image You can rely on ：

[requires]
sdl/2.0.20
sdl_image/2.0.5

[generators]
cmake

You can sdl_image - conan center Find out more about sdl_image Package information . next , Please look like SDL2 A concise tutorial （ One ）： Use Cmake and Conan structure SDL2 Programming environment Just build our code as in .

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Use SDL_IMAGE Import image

sdl_image Very simple to use , Import header file first

#include <SDL_image.h>

next , call IMG_Init() initialization sdl_image

IMG_Init(IMG_INIT_JPG);

at present sdl_image Four formats are supported , Namely ：

• IMG_INIT_JPG
• IMG_INIT_PNG
• IMG_INIT_TIF
• IMG_INIT_WEBP

You can initialize multiple formats at the same time , for example

IMG_Init(IMG_INIT_JPG | IMG_INIT_PNG);

Remember , Call before exiting IMG_Quit() To release resources

IMG_Quit();

Now? , Use IMG_Load() Replace SDL_LoadBMP() To import pictures in other formats

SDL_Surface * image = IMG_Load("PICT3159.JPG");

Finally, paste all the codes ：

#if defined(__cplusplus)
extern "C" {
    
#endif
#include <SDL.h>
#include <SDL_image.h>
#if defined(__cplusplus)
};
#endif

#include <iostream>
using namespace std;

int main() {
    
    bool quit = false;

    SDL_Event event;

    SDL_Init(SDL_INIT_VIDEO);
    IMG_Init(IMG_INIT_JPG);

    SDL_Window *window = SDL_CreateWindow("My SDL Empty window",
                                          SDL_WINDOWPOS_UNDEFINED,
                                          SDL_WINDOWPOS_UNDEFINED,
                                          640, 480, 0);
    SDL_Renderer *renderer = SDL_CreateRenderer(window, -1, 0);
    SDL_Surface *image = IMG_Load("sdl_image.jpeg");
    if (image == nullptr) {
    
        cerr << "SDL_LoadBMP failed\n";
        return -1;
    }
    SDL_Texture *texture = SDL_CreateTextureFromSurface(renderer, image);

    for (; !quit;) {
    
        SDL_WaitEvent(&event);

        switch (event.type) {
    
        case SDL_QUIT: {
    
            quit = true;
            break;
        }
        }
        SDL_RenderCopy(renderer, texture, nullptr, nullptr);
        SDL_RenderPresent(renderer);
    }

    SDL_DestroyTexture(texture);
    SDL_FreeSurface(image);
    SDL_DestroyRenderer(renderer);
    IMG_Quit();
    SDL_Quit();
    return 0;
}

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summary

excellent ！sdl_image It can support pictures in various formats , Need to use IMG_Load Instead of SDL_LoadBMP() that will do . You need to initialize and clean up sdl_image, These are very simple .

All the code in this article can be found in sdl2_tutorial find .