rgb_map(3)

💖 rgb_map(3) — the glow-up lookup table 💖

okay bestie, so this is a page from the Allegro manual — specifically the one about rgb_map, the look up table that speeds up reducing RGB values to palette colors. it's giving Allegro game programming library, and honestly? iconic. ✨

✨ SYNOPSIS ✨

#include <allegro.h>

extern RGB_MAP *rgb_map;

that's it. that's the whole vibe. one little global pointer, so much power. 🫶

🌸 DESCRIPTION 🌸

so here's the tea, bestie: to speed up reducing RGB values to 8-bit paletted colors, Allegro uses a 32k lookup table — and the way that works is it gives 5 bits to each color component. five bits each. cute, compact, efficient. 💅

you must set up this table before you use the gouraud shading routines. like, that's not optional, that's the rule. no table, no gouraud. periodt.

but also — and this is the part that's genuinely obsessed-worthy — if the table is present, it will also vastly accelerate makecol8() and some create_*_table() functions. free speed. we love a multitasker. 👑

and how do you get one of these tables, you ask? two ways, bestie:

• you can precalculate RGB tables with the rgbmap utility 🔥
• or you can generate them at runtime with create_rgb_table() ✨

pick your fighter. either way, you're slaying.

👀 SEE ALSO 👀

your reading list, no skips:

• create_rgb_table(3)
• makecol8(3)
• create_trans_table(3)
• create_light_table(3)
• create_color_table(3)
• ex3d(3)
• excolmap(3)
• exrgbhsv(3)
• exshade(3)
• extrans(3)

and that's the whole page, bestie!! this lil masterpiece came to you straight from the Allegro manual, version 4.4.3 — no date on the footer, just the version, so that's all we're claiming. go set up your lookup table and be free 🦋💖