al_set_shader_sampler(3alleg5)

al_set_shader_sampler 💅✨

okay bestie, we're in the Allegro 5 API manual, page al_set_shader_sampler(3alleg5), and honestly? this one is short but it's giving powerful. 🎀

---

✨ SYNOPSIS ✨

#include <allegro5/allegro.h>

bool al_set_shader_sampler(const char *name,
   ALLEGRO_BITMAP *bitmap, int unit)

---

🦋 DESCRIPTION 🦋

So basically: this function sets a texture sampler uniform and a texture unit for the shader that's currently on your target bitmap. 👑

⚠️ Heads up queen: the bitmap you pass in must be a video bitmap. No exceptions, no shortcuts, no "but it worked that one time". 💀

Now for the part that actually matters — different samplers should use different units. That's the rule. And here's why, because it's lowkey crucial:

The bitmap that gets passed to Allegro's drawing functions uses the 0th unit. So if you're planning on using the al_tex variable in your pixel shader and you've got another sampler in the mix, you gotta set that other sampler to use a unit different from 0. Periodt. 🫶

But wait, there's more (there's always more, and it's kinda iconic):

With the primitives addon, you can actually free up the 0th unit by passing NULL as the texture argument to the relevant drawing functions. 🌈 And in that case? You may set a sampler to use the 0th unit, and thus not use al_tex — because the al_use_tex variable will be set to false. Easy math, bestie. 💖

---

💀 What it returns

Returns true on success. Otherwise it returns false — for example, if the uniform by that name does not exist in the shader. Not me getting a false back and spiralling... 😭

---

⭐ SINCE ⭐

5.1.0 — she's been here a minute, respect her legacy 👑

---

👀 SEE ALSO 👀

• al_use_shader(3alleg5) — go read that one too, it's her bestie fr fr

---

okay so that's the whole page, you ate it, I'm obsessed 💅✨ this was page al_set_shader_sampler(3alleg5) from the Allegro reference manual, and if you ever forget where you read it... that's the source, that's the version, that's the date on the tin, no cap 🎀🦋 bye bestie, go write some shaders 💜