Technical details of my small programs
Contents
Introduction
Articles documenting my tiny graphics programs,
best read in order (for Linux) to see progression.
Most release names are taken from the Star Control
world, one of my favorite adventure game !
Sources can be found here.
Guides
RNG
A pseudorandom
number generator might be useful early on, check out this thread about
tiny PRNG, another good source is this, i used
this one early on in my Linux programs, on modern x86 (~2012)
RDRAND
instruction is also available, good enough random numbers can also
be sourced from RAM etc. sometimes.
LCG
(MCG especially) are probably the smallest ones, they just require
an addition and multiply if the moduli is a power of two.
A naive and primitive one i used on Halite is just using a 8
bits register and an addition (can hardly call that a RNG but it
was good enough for me) : r = (r + 159) & 255
Linux (x86, framebuffer)
2020
2021
- Truespace - 256b
- Flagship - 256b
- Campers - 256b
- QuasiSpace - 128b
- Calculating Space - 256b
- Apollonian - 256b
2022
2023
TIC-80
2021
2022
2023
RISC OS / RPI /
Acorn Archimedes (ARM)
2023
DOS (x86, MCGA / VGA)
2024
p5js/tweet
Introduction
JavaScript / p5js code that i
published on my Twitter account, no definite size goal but
generally less than 256 characters.
Code of this category is not very well size optimized, they
are more to show interesting short algorithms that i discovered on
my own or intro effect that i replicated, made them with
accessibility in mind (so not much arcane code stuff) and to use as
few as possible p5js stuff. (so software rendering / can be ported
easily)
Rotating
Ortho. Cube (2023, ~230 characters)
no polygons, all integers orthographic
cube render
w=128;f=0;setup=_=>createCanvas(w,w);draw=_=>{background(0);loadPixels();f+=.1;s=sin(f);c=cos(f);for(i=h=64;i--;)for(y=h;y--;)for(x=h;x--;){dx=32-x;dy=32-y;pixels[h+(dx*c-dy*s)+(((h+dx*s+dy*c)/2+i)<<7)<<2]=255-i*4};updatePixels()}The idea is to show off the algorithm of many intros (i
believe) which render pseudo 3d iso / ortho objects such as
cubes in
very small code, these objects can be built easily without going
the usual way by iterating on an area with center 0,0 and applying
a transform to the x,y; this produce a shape which can be extruded
down (with an additional loop), this method also works with any
complex shapes eg. a labyrinth or a text as long as you generate
them and extrude them.
using logical operators
The shading can be done by using the extrusion loop value and
more fancy shading such as per face shading is also easily possible
by either doing it as a single pass or on a second pass by
rendering the cube into a buffer and using the buffer to isolate
face from pixel color / horizontal position. (or a
combination)
fancy texturing / shading ! (logical operators,
also note the lighting fakery)
composition, stacking and scrolling, almost
like the cool 256b intro Pixel Town by
Digimind,
note here that the shading is only on the side faces, could also be
applied on the upper face which would appear as a cheap
roof
The rendering of multiple objects is also easy with a second
pass, it can be pretty fast also since it is just a bitmap that is
copied over. :)
multiple objects
2d map made of
tiny patterns to isometric projection and with highly extruded
ortho objects, wave is just a shading trick, still
fairly small
The best way to map the cubes to the screen is to use this
coordinates transform : x = (x - y) and y = (x + y) / 2
To go full 3D from this is not difficult, it will still stay
tiny and fast, just adds 2D rotation to the coordinates, this will
be equivalent to a forward mapping affine renderer (you might have
to downscale the result to remove sampling holes, this can be done
quite easily with scaling; a right arithmetic
shift) and for perspective just add 3D rotation (with pitch
component), texture mapping can also be added easily with the x and
y coordinates and you will get a simple quad forward mapping 3D
renderer at this point, 4-point quadrilaterals can also be made by
adjusting the loop endpoints which would end up being comparable to
a Sega Saturn / 3DO style rasterizer although they also go further
with algorithms to fill the sampling holes, it will be a bit tricky
compared to a triangles based rasterizer but it might do the job in
size limited context or if you don't care about optimal
performances.
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