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<h2 class="center" id="title">MATRIX RAIN: 2025 REFACTOR</h2>
<h6 class="center">21 DECEMBER 2025</h5>
<br>
<div class="twocol justify"><p>The 2022 version worked but had some loose ends. Unicode support was
inflexible–couldn’t mix ASCII with Katakana; Phosphor decay was stored in a
separate array when it should’ve been packed with RGB; Code was harder to read
than it needed to be.</p>
<video style="max-width:100%;" controls="" poster="poster.png">
<source src="matrix.mp4" type="video/mp4" />
</video>
<p>Moved phosphor decay into the 4th byte of the RGB union–should’ve done this
in 2022; What was I thinking.</p>
<p>Keeping the RGB union despite portability concerns. All my systems are
little-endian and the code is cleaner this way.</p>
<p>Fixed Unicode by introducing a charset array. UNICODE(min, max) packs Unicode
ranges into uint64: low four bytes for start, high four bytes for end.
insert_code() unpacks a random block and picks a character from it:</p>
<div class="language-plaintext highlighter-rouge"><div class="highlight"><pre class="highlight"><code>#define UNICODE(min, max) (((uint64_t)max << 32) | min)
static uint64_t glyphs[] = {
UNICODE(0x0021, 0x007E), /* ASCII */
UNICODE(0xFF65, 0xFF9F), /* Half-width Katakana */
};
static inline void insert_code(matrix *mat,
size_t row, size_t col)
{
uint64_t blk;
uint32_t min, max;
blk = glyphs[(rand() % glyphlen)];
min = (uint32_t)blk;
max = (uint32_t)(blk >> 32);
mat->code[index(mat, row, col)] = rand() % (max - min) + min;
}
</code></pre></div></div>
<p>Full-width Katakana breaks column alignment. Stick to half-width
(U+FF61-U+FF9F) range. Compile with -DNOKANA to disable Katakana altogether.</p>
<p>blend() is still good. Leaving it alone.</p>
<p>Tossed license and automake cruft. Just <code class="language-plaintext highlighter-rouge">cc -O3 main.c -o matrix</code> now. Don’t
need the ceremony.</p>
<p>Runs at 2-3% CPU on OpenBSD (T490). No regressions. Fans are quiet.</p>
<p>Commit:
<a href="https://git.asciimx.com/matrix-digital-rain/commit/main.c?id=69a888a5b0bc4ef4bce4f86c1556a06f0f131fda">69a888a</a></p>
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<p class="post-author right">by W. D. Sadeep Madurange</p>
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