设置 window 大小后，SDL 未呈现完整 window

Question

下面是我使用SDL加载图片的步骤。

创建 window 并以默认大小呈现，例如 100x100
使用 IMG_LoadTexture
查询纹理信息并获取纹理尺寸，例如800x600，然后使用SDL_SetWindowSize调整到所需尺寸
执行渲染

结果是window创建时SDL只渲染到100x100区域，其他部分不渲染。

如何在 SDL_SetWindowSize 之后使 SDL 渲染完整 window？

下面是我的示例代码

#include <iostream>
#include <SDL_image.h>
#include "SDL.h"

int main(int argc, char *argv[])
{
SDL_Window* sdlWindow;
SDL_Renderer* sdlRenderer;
SDL_CreateWindowAndRenderer(100, 100, 0, &sdlWindow, &sdlRenderer);

IMG_Init(IMG_INIT_JPG);

SDL_Texture* sdlTexture = IMG_LoadTexture(sdlRenderer, "test-wallpaper-800x600.jpg");

Uint32 format;
int access, w, h;
if (SDL_QueryTexture(sdlTexture, &format, &access, &w, &h) == 0) {
    SDL_SetWindowSize(sdlWindow, w, h);
    SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, "linear");
    SDL_RenderSetLogicalSize(sdlRenderer, w, h);
}

SDL_RenderClear(sdlRenderer);
SDL_RenderCopy(sdlRenderer, sdlTexture, NULL, NULL);
SDL_RenderPresent(sdlRenderer);

SDL_Event sdlEvent;
while (SDL_WaitEvent(&sdlEvent)) {
    if (sdlEvent.type == SDL_WINDOWEVENT
        && sdlEvent.window.event == SDL_WINDOWEVENT_CLOSE) {
        break;
    }
    if (sdlEvent.type == SDL_KEYDOWN
            && sdlEvent.key.keysym.sym == SDLK_ESCAPE) {
        break;
    }
}

SDL_DestroyRenderer(sdlRenderer);
SDL_DestroyWindow(sdlWindow);
return 0;
}

Answer 1

您没有看到更新的渲染，因为您只在帧循环之前渲染了一次。要解决此问题，请将渲染移到帧循环中，如下所示：

SDL_Event sdlEvent;
while (SDL_WaitEvent(&sdlEvent))
{
    if (sdlEvent.type == SDL_WINDOWEVENT
        && sdlEvent.window.event == SDL_WINDOWEVENT_CLOSE) {
        break;
    }
    if (sdlEvent.type == SDL_KEYDOWN
            && sdlEvent.key.keysym.sym == SDLK_ESCAPE) {
        break;
    }

    // Render here
    SDL_RenderClear(sdlRenderer);
    SDL_RenderCopy(sdlRenderer, sdlTexture, NULL, NULL);
    SDL_RenderPresent(sdlRenderer);
}

设置 window 大小后，SDL 未呈现完整 window

SDL not render to the full window after set window size

c++

sdl

sdl-2