Tag: Common Lisp
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FFMPEG input/output as an abstraction
I am currently working on writing code to support the usage pattern that I have used in the past for making animations using ffmpeg to encode video. Really though, how complex does it need to be? Well, let’s put together a wish-list: It should always shut down the pipe at the end of executionIt’s really…
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L-Systems with shapes
Rendering shapes is a relatively small addition to the L-System code I’ve been implementing over the last few weeks, it consists of a few manual dispatches to drawing code based on the first symbol in a sublist. The immediate alternative is using defgeneric and the common lisp object system, which is probably the correct thing…
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Improving On L-Systems
The simplest implementation of L-Systems requires term-rewriting, and maybe turtle graphics. We already have arbitrary computation on the execution end, but what if we could add computation on the term rewriting phase? We can get a lot more flexibility without adding an infinite number of rules. Also the last L-System post has had its code…
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Some Thoughts on Codex, a Common Lisp Documentation Tool
Codex is one of a small number of native documentation generators in lisp. It uses an unusual markdown format called Scriba. I have been using it to document img-genner since about 2 years ago. In those two years there hasn’t been an update for it(Actually for at least 7), but that’s not terribly uncommon among…
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L-Systems
L-Systems are a type of fractal, well, that’s not really true; L-systems are a formalism for constructing rules for iterated systems, such as plant growth and turning those into images. But what’s interesting is that they’re actually remarkably simple to implement the evaluation of. So let’s look at one of the simpler ones, the binary…
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Particles Tunneling Through Solid Earth
No, I’m not going to write about neutrinos, or anything else that is ‘real’. Pixels are the particles of today’s post. Their universe is very different than ours, it is solid in all directions, it is quantized(at a different level than ours). At each moment, there are a countable number of choices. To be a…
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Recreating an old Visualizer I swear I saw
I have vague memories of a visualizer that I will likely never encounter without looking for it again. It was a waveform display but it had these rectangles that would ride them like boats, not really like surfing. Now, you might be wondering why I’m doing this when my library creates, at best, video. Well,…
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img-genner Switching away from cl-png
cl-png is a long lived package that mostly works, but it contains a single flaw, it relies on the presence of a library and the competence of the implementation in getting to it. It grabs the source and tries to build it. That’s one reason that I don’t much care for it. As much as…
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Rescaling Video Using img-genner
There’s not much of a reason to do this because ffmpeg has a much faster and nicer scaler, but maybe we want to write common lisp to handle an effect. When I introduced img-genner, I wasn’t sure that this was the direction to take, but now it seems appropriate, if nothing else. You will most…
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Animating direct to mp4 with img-genner
Two posts ago I started talking about img-genner. Guiding my authorship of the library by using it. Today I made a change that allows for what I think are exciting possibilities. One of the best uses I’ve found for this library has been using it to generate animations, surprisingly I’ve started to take a liking…