hakanai

This was an idea for tree implementation I came up with to try and play well with the way Compose wants us to do things.

The basic idea:

• Maintain a list of every row which is currently visible/expanded
• When you expand a node, add all its children to the list
• When you collapse a node, remove its children (caveat: and their children) from the list
• Rendering nodes is fairly easy because the only thing that varies is the amount of indent and which icon to show

The idea seems sound - adding a million entries to the list is fast enough as to be unnoticeable.

hakanai

.DS_Store pBB0 blob format

This blob contains many values which look like file offsets, but the blob itself isn't big enough for any of the offsets to make sense, so they must be offsets inside some other, larger structure. Possibly the pBBk entry?

Header

hakanai

code point	ch	expanded	meaning
U+3300	㌀	アパート	apartment?
U+3301	㌁	アルファ	alpha (α)
U+3302	㌂	アンペア	ampere (A)
U+3303	㌃	アール	are (a)
U+3304	㌄	イニング	inning?
U+3305	㌅	インチ	inch (in.)
U+3306	㌆	ウォン	won (₩)
U+3307	㌇	エスカード

hakanai

meta:
  id: macos_bookmark_file
  endian: le
  #file-extension: macos-bookmark-file

seq:
  - id: header
    type: header
  - id: toc_offset
    type: u4

hakanai

import androidx.compose.desktop.Window
import androidx.compose.material.*
import androidx.compose.runtime.*
import androidx.compose.ui.graphics.Color

fun isSystemInDarkTheme(): Boolean {
    // TODO: On Android, presumably this is `AppCompatDelegate.getDefaultNightMode()`.
    //       What is it on Desktop?
    return false
}

hakanai

PMX (Polygon Model eXtended) 2.1

This is an English description of the .PMX file format used in Miku Miku Dance (MMD).

PMX is the successor to the .PMD format (Polygon Model Data).

This is work-in-progress! Please leave feedback in the comments.

Todo

hakanai

import java.text.BreakIterator
import java.text.StringCharacterIterator

fun reverse(string: String): String {
    val iterator = BreakIterator.getCharacterInstance()
    iterator.text = StringCharacterIterator(string)
    val characters = mutableListOf<String>()
    while (true) {
        val startOffset = iterator.current()
        if (iterator.next() == BreakIterator.DONE) {

hakanai

Modelling Light

I wanted to improve the realism of ray traced images.

Real light waves are not conveniently split into RGB components, but rather a spectrum. Further, light exhibits polarisation and diffraction.

A spectrum

hakanai

RFL File Format Notes

The RFL file format was used by Wavefront's Advanced Visualizer software to store "spectral curve data", which is essentially a way to encode the response of a material to different wavelengths of light.

The docs for the [MTL file format][1] frequently refer to this format, but never seem to include the documentation for the format.

hakanai

import numpy
import bpy
import bmesh
from math import sqrt, floor
from bpy import context
from scipy.special import ellipj, ellipk

Kval = ellipk(0.5) # 1.8540746773013719

def elliptical_map(x, y):