SDL2 无法正确绘制矩形

Posted 2023-02-22

【中文标题】SDL2 无法正确绘制矩形

【英文标题】：SDL2 Wont draw Rectangles Correctly

【发布时间】：2018-09-25 05:07:10

【问题描述】：

我正在创建一个窗口并绘制一个框，但由于某种原因，我没有绘制一个框，而是将屏幕更改为该颜色。我附上了窗口外观的照片，我将附上源代码。

#include <iostream>
#include <SDL.h>
#undef main

using namespace std;
int SCREEN_WIDTH = 650;
int SCREEN_HEIGHT = 650;

int main() 
    if (SDL_Init(SDL_INIT_VIDEO) != 0) 
        std::cout << "SDL_Init Error: " << SDL_GetError() << std::endl;

        return 1;
    

    SDL_Window *window = SDL_CreateWindow("Cells", 100, 100, SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_SHOWN);
    if (window == nullptr) 
        std::cout << "SDL_CreateWindow Error: " << SDL_GetError() << std::endl;

        SDL_Quit();

        return 1;
    

    SDL_Renderer *renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);
    if (renderer == nullptr) 
        std::cout << "SDL_CreateRenderer Error: " << SDL_GetError() << std::endl;

        SDL_DestroyWindow(window);
        SDL_Quit();

        return 1;
    

    SDL_Event event;
    bool quit = false;

    while (!quit) 
        while (SDL_PollEvent(&event)) 
            if (event.type == SDL_QUIT) 
                quit = true;
            
        

        SDL_RenderClear(renderer);
        // renderTextures
        SDL_Rect fillRect =  122, 122, 122, 122;
        SDL_SetRenderDrawColor(renderer, 255, 255, 255, 255);
        SDL_RenderFillRect(renderer, &fillRect);
        SDL_RenderPresent(renderer);
    

    return 0;

Doesn't Draw Correctly

【参考方案1】：

SDL_RenderClear 使用您修改的当前绘制颜色，因此您的清晰和矩形颜色是相同的。使用例如设置不同的清晰颜色（您想要的背景颜色），例如

    SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);
    SDL_RenderClear(renderer);
    // now draw your rectangles with different col