1. Project Configuration (CMakeLists.txt) 1. Конфигурация проекта (CMakeLists.txt)

set(CMAKE_BUILD_TYPE "Debug")

cmake_minimum_required(VERSION 3.21)
project(rectangle-sdl3-c)

set(SDL3_DIR "C:/libs/SDL3-devel-3.4.8-mingw/lib/cmake/SDL3")
find_package(SDL3 REQUIRED)

add_executable(app)

target_sources(app
PRIVATE
    src/main.c
)

target_link_libraries(app PRIVATE SDL3::SDL3)

target_link_options(app PRIVATE -mconsole)

set(CMAKE_BUILD_TYPE "Debug")

cmake_minimum_required(VERSION 3.21)
project(rectangle-sdl3-cpp)

set(SDL3_DIR "C:/libs/SDL3-devel-3.4.8-mingw/lib/cmake/SDL3")
find_package(SDL3 REQUIRED)

add_executable(app)

target_sources(app
PRIVATE
    src/main.cpp
)

target_link_libraries(app PRIVATE SDL3::SDL3)

target_link_options(app PRIVATE -mconsole)

2. Source Code (The Callback Structure) 2. Исходный код (Структура Callback)

#define SDL_MAIN_USE_CALLBACKS 1 // Use callback functions instead of main()

#include <SDL3/SDL.h>
#include <SDL3/SDL_main.h>

// We will use this renderer to draw into this window every frame
static SDL_Window *window = NULL;
static SDL_Renderer *renderer = NULL;

// This function runs once at startup
SDL_AppResult SDL_AppInit(void **appstate, int argc, char *argv[])
{
    if (!SDL_Init(SDL_INIT_VIDEO))
    {
        SDL_Log("Couldn't initialize SDL: %s", SDL_GetError());
        return SDL_APP_FAILURE;
    }

    if (!SDL_CreateWindowAndRenderer("SDL3 Rectangles", 500, 500, SDL_WINDOW_RESIZABLE, &window, &renderer))
    {
        SDL_Log("Couldn't create window/renderer: %s", SDL_GetError());
        return SDL_APP_FAILURE;
    }

    SDL_SetRenderVSync(renderer, 1);

    return SDL_APP_CONTINUE; // Continue program execution!
}

// This function runs whenever a new event occurs (mouse input, key presses, etc.)
SDL_AppResult SDL_AppEvent(void *appstate, SDL_Event *event)
{
    if (event->type == SDL_EVENT_QUIT)
    {
        return SDL_APP_SUCCESS; // Terminate the program, reporting success to the OS
    }
    return SDL_APP_CONTINUE; // Continue program execution!
}

// This function runs once per frame and is the heart of the program
SDL_AppResult SDL_AppIterate(void *appstate)
{
    SDL_SetRenderDrawColor(renderer, 38, 43, 51, 255);

    // Clear the window with the draw color
    SDL_RenderClear(renderer);

    SDL_FRect rect;
    rect.x = 100;
    rect.y = 50;
    rect.w = 200;
    rect.h = 60;
    SDL_SetRenderDrawColor(renderer, 220, 80, 80, SDL_ALPHA_OPAQUE);
    SDL_RenderFillRect(renderer, &rect);

    // Present the freshly cleared result to the screen
    SDL_RenderPresent(renderer);

    return SDL_APP_CONTINUE; // Continue program execution!
}

// This function runs once upon shutdown
void SDL_AppQuit(void *appstate, SDL_AppResult result)
{
    // SDL will clean up the window and renderer for us
}

3. Why use this? 3. Зачем это использовать?

The SDL_AppIterate function is called by the OS whenever it is ready to render a frame. This allows browsers to pause your game when the tab is inactive and mobile phones to save battery. Функция SDL_AppIterate вызывается ОС всякий раз, когда она готова к отрисовке кадра. Это позволяет браузерам приостанавливать игру, когда вкладка неактивна, а мобильным телефонам — экономить заряд батареи.