在SDL2中隨時間變化的窗口顏色

我在SDL2中創建了一個以紅色打開的窗口。我需要窗口在幾秒鐘之後改變顏色，並且只要窗口打開，就繼續這樣做。因此，窗戶可能會打開紅色，停留五秒鐘，然後變爲綠色五秒鐘，然後變爲藍色五秒鐘，然後循環回紅色並再次開始整個過程。在SDL2中隨時間變化的窗口顏色

int WindowOpen() { 

bool quit = false; 

SDL_Window *window;     // Declare a pointer 

SDL_Init(SDL_INIT_VIDEO);    // Initialize SDL2 

             // Create an application window with the following settings: 
window = SDL_CreateWindow(
    "My SDL2 window",     // window title 
    SDL_WINDOWPOS_UNDEFINED,   // initial x position 
    SDL_WINDOWPOS_UNDEFINED,   // initial y position 
    640,        // width, in pixels 
    480,        // height, in pixels 
    SDL_WINDOW_OPENGL     // flags - see below 
    ); 

SDL_Renderer *renderer = NULL; 
renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED); 
SDL_Event* MainEvent = new SDL_Event(); 
SDL_RenderClear(renderer); 

// Up until now everything was drawn behind the scenes. 
// This will show the new, red contents of the window. 
SDL_RenderPresent(renderer); 

// Check that the window was successfully created 
if (window == NULL) { 
    // In the case that the window could not be made... 
    printf("Could not create window: %s\n", SDL_GetError()); 
    return 1; 
} 

SDL_SetRenderDrawColor(renderer, 255, 0, 0, 255);//red. Was testing to see if window would open red and change to green then blue but this doesn't work. 
//SDL_Delay(3000); 
//SDL_SetRenderDrawColor(renderer, 300, 150, 0, 155);//green 
//SDL_Delay(3000); 
//SDL_SetRenderDrawColor(renderer, 129, 150, 500, 105);//blue 

while (quit == false && MainEvent->type != SDL_QUIT) { //While quit is false, run window and renderer. 
    SDL_PollEvent(MainEvent); 
    SDL_RenderClear(renderer); 
    SDL_RenderPresent(renderer); 
} 


// The window is open: could enter program loop here (see SDL_PollEvent()) 

//SDL_Delay(3000); // Pause execution for 3000 milliseconds, for example 

// Close and destroy the window 
SDL_DestroyWindow(window); 
SDL_DestroyRenderer(renderer); 
delete MainEvent; 

// Clean up 
SDL_Quit();

}

來源

2016-11-01 ConfusedProgrammer

SDL_SetRenderDrawColor是剛剛設置的顏色渲染器繪製，如果你問它。要使用該顏色填充後臺緩衝區，您應該使用SDL_RenderClear進行跟進。隨着後臺緩衝區填充，然後在屏幕上繪製它，你需要撥打SDL_RenderPresent。

while (quit == false && MainEvent->type != SDL_QUIT) { //While quit is false, run window and renderer. 
    SDL_SetRenderDrawColor(renderer, 255, 0, 0, 255);//red. Was testing to see if window would open red and change to green then blue but this doesn't work. 
    SDL_RenderClear(renderer); 
    SDL_RenderPresent(renderer); 
    SDL_Delay(3000); 
    SDL_SetRenderDrawColor(renderer, 300, 150, 0, 155);//green 
    SDL_RenderClear(renderer); 
    SDL_RenderPresent(renderer); 
    SDL_Delay(3000); 
    SDL_SetRenderDrawColor(renderer, 129, 150, 500, 105);//blue 
    SDL_RenderClear(renderer); 
    SDL_RenderPresent(renderer); 
    SDL_Delay(3000); 

    SDL_PollEvent(MainEvent); 
}

改變你的主循環到類似的東西會做類似於你想要的，但延遲是三秒鐘。另外，這樣您的主循環將需要9秒才能執行，這意味着退出的事件處理可能需要9秒。這不是很好，但修復它是作爲讀者的練習。

來源

2016-11-01 07:59:29

在SDL2中隨時間變化的窗口顏色

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