exzbuf(3)

💖 exzbuf — bestie's guide to Z-buffered polygons 💖

okay so real talk, this is a page out of the Allegro manual, and it's the exzbuf example — yes, that's the man page name, it lives in section 3 (library calls, for the uninitiated, iykyk). pull up a chair, grab a boba, we're doing 3D math today. 🧋✨

✨ SYNOPSIS ✨

#include <allegro.h>

Example exzbuf

that's it. that's the whole vibe. one include and a whole demo. slay. 💅

🌈 DESCRIPTION 🌈

so this program is literally a whole tutorial in disguise. it demonstrates how to use Z-buffered polygons plus the floating point 3D math routines, and honestly? it ate. 🔥

it also gives you a simple way to compute fps (that's frames per second, bestie, the number that lives in the corner of every gamer's screen) using a timer. periodt.

here's the plot: first you pick a screen resolution through the standard GUI dialog — yes, the classic Allegro one, you know the one 🎀 — and then the example hits you with two 3D cubes, rotating, intersecting each other, just doing their little main character thing. 🧊🧊

and the why is the best part, so listen: instead of having full polygons incorrectly overlap other polygons because of per-polygon sorting (the messy, wrong, lowkey embarrassing way), each pixel is drawn at the correct depth. per pixel. correct depth. that's the whole Z-buffer flex. 💚

ngl this is the moment where 3D graphics just clicks for people. the depth thing. you'll see.

👀 SEE ALSO 👀

the full friend group, no one left out, fr fr:

• BITMAP(3), END_OF_FUNCTION(3), END_OF_MAIN(3), LOCK_FUNCTION(3), LOCK_VARIABLE(3), MATRIX_f(3)
• PALETTE(3), POLYTYPE_GCOL(3), SCREEN_H(3), SCREEN_W(3), V3D_f(3), ZBUFFER(3)
• allegro_error(3), allegro_exit(3), allegro_init(3), allegro_message(3), apply_matrix_f(3), bitmap_color_depth(3)
• blit(3), clear_bitmap(3), clear_zbuffer(3), create_bitmap(3), create_zbuffer(3), desktop_palette(3)
• destroy_bitmap(3), destroy_zbuffer(3), font(3), get_transformation_matrix_f(3), gfx_mode_select_ex(3), install_int(3)
• install_keyboard(3), install_mouse(3), install_timer(3), keypressed(3), palette_color(3), persp_project_f(3)
• polygon_z_normal_f(3), quad3d_f(3), readkey(3), screen(3), set_color_depth(3), set_gfx_mode(3)
• set_palette(3), set_palette_range(3), set_projection_viewport(3), set_zbuffer(3), textprintf_ex(3), vsync(3)

like. the whole roster. go read them, they're all right there. 🫶

and that's the page!! this one's from the Allegro crew, version 4.4.3, and it's filed under exzbuf(3) in section 3 — so when you're out here writing your own Z-buffered 3D masterpiece, you know exactly who to thank. 💜✨ bye bestie, go render something gorgeous!! 🦋🌸