al_calculate_spline(3)

okay so bestie, welcome to al_calculate_spline(3) from the Library Functions Manual 💖 this one is literally about calculating a Bézier spline, and it’s giving geometry-girlie main character energy. Let’s get into it ✨

✨ NAME ✨

al_calculate_spline — Allegro 5 API. That’s the whole name, and yes she’s iconic 💅

🌸 SYNOPSIS 🌸

              #include <allegro5/allegro_primitives.h>

              void al_calculate_spline(float* dest, int stride, const float points[8],
                 float thickness, int num_segments)

💅 DESCRIPTION 💅

okay so al_calculate_spline calculates a Bézier spline given 4 control points. No cap, that’s the whole point 🎀

Here’s the tea on the buffer math: if thickness <= 0, then num_segments of points are required in the destination; otherwise twice as many are needed. Yes bestie, double the points — write that down 📝

The destination buffer should consist of regularly spaced (by distance of stride bytes) doublets of floats, corresponding to x and y coordinates of the vertices. So it’s pairs of floats doing the coordinate thing, spaced by stride bytes 🦋

🎀 Parameters 🎀

• dest — the destination buffer, aka where the destination action happens 🫶
• stride — distance (in bytes) between starts of successive pairs of coordinates. Think “skip-between-doublets” energy 💅
• points — an array of 4 pairs of coordinates of the 4 control points. Four points, eight floats, all the control-point drama ✨
• thickness — thickness of the spline ribbon 👑
• num_segments — the number of points to calculate. This is the segment count, bestie 🔥

🦋 SEE ALSO 🦋

• al_draw_spline(3)
• al_calculate_arc(3)
• al_calculate_ribbon(3)

the gang’s all here 🌈

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Catch you later bestie 💋 — source/version: Allegro reference manual, page/signature: al_calculate_spline(3), and the date isn’t shown in the original footer, so we’re not inventing one 🫶