Insaturé

For a long time I’ve been wanting to Migrate my blog system from Pelican to Hugo. One reason is that I had enough with python virtual environment breaks every 3 months. Another motivation is obviously I would like to replace Python with Go in my life.

A long time ago I followed Go tutorial for getting started, surprised by its syntax tidiness and similarity to Python, and it is way faster. But soon I found out it would be one of this thing I learned for a weekend and forget all together, since I don’t have any projects I would use it actively. Now after one month of procrastination, I finally pieces ALMOST everything to reproduce my old blog. Time for a summary.

It’s been a while that I haven’t update the blogs. It is so easy to slack off on good habits. “Oh I will continue once I finish A B C”. We are all busy as hell, in the software world, you WORK, you WORK and you GO TO SLEEP. Like this one, I am always hoping to switch to Hugo, then I can continue writing the blog. The thing is, I never got the good weekend to do the switching. Weekends are really no for staying at home confronting monitors.

I am now back in Canada, quarantined again. There is much of internal struggle whether I should move back or stay in Shanghai? Working for tech company in Shanghai or many cities in China would be like endless crunching. Maybe I was not used to this high-paced lifestyle, long working hours. Didn’t like javascript either. It is a pity that I didn’t find a nicer job maybe opens to better opportunities. I was focusing on the development of Taiwins back then, well it is working now and I don’t develop it anymore. The June was pretty unproductive, ever since the ICL implant surgery I couldn’t use computers for long, even now it is painful to do so. At least I get more time reading books?

In my previous post, I’ve somewhat found a way to synchronize my org files. I was pretty happy, I was having just around six org pages, coping them to a webdav server was not a huge hustle :P, util I started to use org-roam. Suddenly I have to create org file for every new zettle, the performance quickly started to tank. This is probably the beauty and curse of using open source solutions — you have full control of your work and you have to solve problems you created yourself.

Static site generator, I love and hate them at the sametime. They really render your markdowns into a beautiful website without need of knowing web technologies. Then there are the constant hustles once you try to customize it, change a theme, adding different functionalities or upgrade. It is YOUR website, you want it look different than others, right. At some point, whether you like it or not, the SSG users will take the role of website designers by tangling with CSS.

If there is one thing I’d like to commit it must be the my time mangement improvements. For that purpose, Emacs Org-mode is the ultimate tool for programmers. I can keep my notes nicely and I can track my tasks/errands all together. But all my notes are stored in my linux box, I lose access to them once I am away. From that reason, I was always on-and-off with using org-mode due to the portability. We are not in the age doing everything with desktop anymore, more often I need to track my TODOs from cellphone as well.

I hate every single line of xwayland code I wrote, it is ugly, long and hard to maintain. Now I know very well why there is wayland in the first place, sadly a complete wayland compositor has to bring a piece of crap of X with it. I just finished the selection handling in xwayland by mimicing weston code. After finally understand that 1000 lines of confusing code, I just found out I can’t do any better.

Folks, the Magical year of 2020 is behind us, and it wasn’t a happy new chapter waiting us. Man, I still couldn’t believe, once per 100 years, why it was us who have to face the coronavirus. Now I take a good look of my 2020, I went from trying to submit a xcbcommon handling patch to weston to writing a full wayland compositor from scratch. It was not my plan!!! Taiwins should have being a rather simple application on top of the libweston, the so called “reference compositor “, but libweston cannot change keyboard layout once launching, nor it can support cloning output, there are new bugs when you digging deep. The worst is that it breaks the library into different shared modules, and changes lib location every release. It was like it really does not want to link to it. The codebase was old and long, it was difficult to make a change and really difficult to get libweston taking a patch. Then there is the wlroots. If it was released half year earlier Taiwins would probably sit on top of that. But, screw it. I am doing it myself.

In the first blog of libdrm, we went through the repainting loop using the libdrm. Now we move on to the topic of framebuffers. A framebuffer is a piece of memory (could be on main memory or on GPU) for repainting every frame. It is like a canvas, represents what you would finally see on screen. Framebuffer is already a familiar concept to rendering programmers, in OpenGL, We have GL_FRAMEBUFFER_0 for presenting the surface, additional framebuffers for roles like G-Buffer and post-processing. In GPU programming, framebuffer is also a broader concept, “abstraction of a collection of attachments”, the underlining attachments corresponds to actual pieces of memory we talk about here.

As the taiwins project finished with X11/Wayland backend rigging. Now I am fully on the libdrm backend development, dealing with hardwares directly. This backend requires 200 percent my energy to tame the complexity.

Like other backends, libdrm also needs to provide two resources, input and output. Backends like nested wayland backend or X11 backend, the output device are the windows created by ourselves (or by the user). Meaning we can create it or destroy it as we please. As for libdrm, those are provided by the OS. An output in libdrm’s terminology, is called connector. We query and change the connectors state by drmModeGet* functions. Then later set the hardware states by drmModeSet* or the new atomic API. It may sound simple but actually, for displaying images on the screen using the libdrm mechanism, it takes quite a few components, working together, to achieve the goal. We uses drmMode* routines for kernel-modesetting; libgbm for framebuffer allocation; OpenGL or Vulkan for rendering. If done right, you would get tear-free images on your screen constant refresh rate. But should anything goes wrong, you probably end up with a black screen.