IrisCaves — Alex's Caves × Shaders

Alex's Caves looks incredible without shaders and kind of falls apart with them. Its cave biomes lose their colored fog and glow, the primordial boss stops painting the sky red, and half its projectiles turn invisible. IrisCaves fixes that — it teaches your shader pack about Alex's Caves so the two finally play nice.

No pack editing, no "download this special version." Drop the mod in, keep the shader pack you already use, and IrisCaves quietly writes a patched copy next to it.

What it does

• Biome atmosphere. The six Alex's Caves cave biomes get their real fog color back under shaders — the toxic green, the primordial gold, the abyssal blue, and so on.
• Luxtructosaurus. When the primordial boss is active, the sky and fog turn the same ominous red it uses in vanilla, overriding the normal cave color. Fully tunable (color + strength).
• Deepsight. The Deepsight effect actually brightens dark areas again, so you can see with it on.
• Invisible things, visible again. Sea Staff bolts, the Dreadbow's shadow arrows, the thrown Extinction Spear, totem/dinosaur spirits, ferrouslime gel, the Bubbled effect — all of these vanish under shaders normally. IrisCaves makes them show up.

Everything above ships with in-game sliders on Complementary (under Shader options → Lighting Settings → Alex's Caves Biome Lighting).

How it works

On launch, IrisCaves finds a supported pack in your shaderpacks/ folder and writes a patched copy called <pack>_iriscaves. Your original pack is never touched. Pick the _iriscaves version in the shader menu and you're done. It's a normal pack — no dependency on Oculus internals, so it keeps working across Oculus updates.

Supported shaders

Works best on the Complementary family — Complementary Reimagined or Unbound together with Euphoria Patches — where you get the full feature set plus the settings GUI.

It also supports BSL, Bliss, and Solas, with the most portable effects (biome cave-fog tint + the red boss atmosphere). Other packs are left untouched rather than broken. The biome and boss detection runs on the Java side, so it's accurate regardless of pack.

Note: the brightness tweaks (Forlorn Hollows darkness, Candy/Primordial sunlit look) and the settings sliders are Complementary-only — they rely on lighting internals the other packs don't share.

Requirements

• Minecraft 1.20.1, Forge
• Oculus (Iris for Forge) — this is a shader companion, so you need a shader runtime
• Alex's Caves (+ Citadel)

Client-side only. Safe to add or remove at any time.

FAQ

Do I need a special shader pack? No. Use any supported pack you already have — the mod makes the patched copy for you.

It made a second pack in my list. That's the point — <pack>_iriscaves is the patched one. Select it.

Some effect looks off on BSL/Bliss/Solas. Those get the lightweight integration; you can fine-tune the colors in lib/misc/alexCavesBiomes.glsl inside the generated pack.