如何在C++的SDL2中解决16x16纹理像素尺寸不一致问题？

我的纹理所有像素尺寸不一致，且会随图像大小变化，小尺寸下该问题表现得尤为突出。我尝试过放大图像，但问题并非出在图像文件本身。

问题演示 #

相关代码 #

纹理加载函数 #

SDL_Texture* loadTexture(std::string path)
{
    //The final texture
    SDL_Texture* newTexture = NULL;

    //Load image at specified path
    SDL_Surface* loadedSurface = IMG_Load(path.c_str());
    //Create texture from surface pixels
    newTexture = SDL_CreateTextureFromSurface(renderer, loadedSurface);

    //Get rid of old loaded surface
    SDL_FreeSurface(loadedSurface);

    return newTexture;
}

主函数 #

int main(int argc, char* args[])
{
    SDL_Texture* loadTexture(string path);

    window = SDL_CreateWindow("Euka", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_SHOWN);
    renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED && SDL_RENDERER_PRESENTVSYNC);

    //Initialize renderer color
    SDL_SetRenderDrawColor(renderer, 0xFF, 0xFF, 0xFF, 0xFF);

    //Initialize PNG loading
    int imgFlags = IMG_INIT_PNG;
    builderCreatureTexture = loadTexture("Assets/builderCreature.png");

    int xPos = 200;
    int yPos = 200;

    while (running)
    {

        //Initialize renderer color
        SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);
        SDL_RenderClear(renderer);

        //Draw Here-----

        for (int x = -20; x < 20; x++)
        {
            SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);
            SDL_RenderClear(renderer);
            creature.DrawCreature(renderer, builderCreatureTexture, xPos, yPos, globalSize + x);
            SDL_RenderPresent(renderer);
            SDL_Delay(80);
        }
        //-----Draw Here

        SDL_RenderPresent(renderer);
        }
}

修复方案 #

1. 修正渲染器参数错误
   你在创建渲染器时用了逻辑与&&，这会导致标志位被错误转换，应该用按位或|来组合渲染器属性：

   renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);
   

2. 设置纹理的最近邻缩放模式
   默认的线性过滤会导致小尺寸缩放时像素模糊、尺寸不均，改成最近邻过滤可以保留像素硬边缘，避免变形。在创建纹理后添加以下代码：

   SDL_SetTextureScaleMode(newTexture, SDL_ScaleModeNearest);
   

   位置放在SDL_CreateTextureFromSurface之后、SDL_FreeSurface之前。

3. 检查绘制逻辑的精度
   确保DrawCreature函数中计算目标矩形时没有整数截断偏差，比如使用浮点数临时存储缩放后的尺寸，再转换为整数时做适当取整处理。

内容的提问来源于stack exchange，提问作者ItsJustLogic