Demoscene
A demo is a program that produces a film. No image files, no samples, no engine — the picture and the sound are both computed, from arithmetic, at runtime. These articles work through the parts of that discipline that are real engineering rather than folklore: sphere tracing a distance field, band-limiting an oscillator, keeping a framebuffer in linear light, and getting a renderer to use every core it has. Every one of them is grounded in code that is public and that builds.
4 articles
Bloom in linear light, and what sRGB averaging costs
Averaging black and white in sRGB gives code 128 where the physically correct answer is code 188, and every blur, downsample and bloom pays that error
A parallel for over one atomic counter
Splitting an uneven render into eight contiguous blocks reached 2.95x on eight threads. Handing rows out from one atomic counter reached 6.16x, on the same work
PolyBLEP: two samples that fix oscillator aliasing
A naive sawtooth at 1199.71 Hz puts alias energy 15.15 dB under its harmonics. A two-sample polynomial correction pushes it to 31.71 dB, for six flops
Sphere tracing: the step that must not overshoot
A distance field that overestimates distance makes sphere tracing unsafe. In this tunnel the gradient bound is 1.1833, so only 0.8451 of each step is safe
Related topics
Graphics Programming
Software rendering with no GPU: signed distance fields, sphere tracing, linear-light framebuffers, bloom over a mip pyramid, tone mapping and dithering.
Scientific Computing
The implementation layer beneath engineering analysis: floating-point determinism, memory layout, sparse data structures and the C that carries a solver.
Systems Programming
C and C++ close to the machine: memory layout, atomics and thread pools, what the compiler is allowed to assume, and measurements that settle it.
Audio DSP
Sound synthesised from arithmetic: band-limited oscillators, state variable filters, envelopes and reverb, and the aliasing that decides how they sound.