There's no specific filter. The main effect is blending the previous frame with the current frame. When blending, I modify the coordinates and add some noise. This makes the graphics look less basic and it creates this noisy trail when things move.
It seems so un-FORTRAN that DEC had a FORTRAN compiler for the PDP-11. that was based on a stack machine and then later built an FP accelerator specialized to accelerate the stack machine. It was a straggler but I'm still trying to track down a circa 1992 article from Dr. Dobb's Journal where someone used virtual machine techniques to unbreak the broken i860 and make a good FORTRAN compiler.
It's incredibly satisfying to see the polar opposite of the usual LLM/superDB/K8/CICD/Cloud/Container/Crapola corpobloat we hear about on this site all the time, namely a tiny piece of handcrafted code, ironically produce something infinitely more aesthetically beautiful, and intellectually interesting from an almost artisan engineering perspective.
Of the many cool things I liked about this, removing the missile from the array by swapping it with the last missile and decrementing the missile count was a nice trick.
9 comments
[ 3.7 ms ] story [ 38.7 ms ] threadEdit: Thanks for the downvote, guess I shouldn't have paid any attention to this post at all?
The source code is here: https://github.com/laurentlb/shmup8/blob/main/src/shaders/sc...
Blending is on lines 241, 242.
I didn't try to get a specific 80s look, I just played with formulas.
https://en.wikipedia.org/wiki/CHIP-8
and
https://en.wikipedia.org/wiki/SWEET16
It seems so un-FORTRAN that DEC had a FORTRAN compiler for the PDP-11. that was based on a stack machine and then later built an FP accelerator specialized to accelerate the stack machine. It was a straggler but I'm still trying to track down a circa 1992 article from Dr. Dobb's Journal where someone used virtual machine techniques to unbreak the broken i860 and make a good FORTRAN compiler.
https://itch.io/jam/langjamgamejam/entries
There were some really impressive submissions in spite of the short time frame!