Aeon Realism

A realistic, cinematic shader pack for Iris — built around one rule: look expensive, run cheap.

No path tracing. No full-resolution ray tracing. Every stochastic effect — shadows, ambient occlusion, global illumination, reflections, volumetrics — is deliberately under-sampled, dithered with a different pattern each frame, and resolved by TAA. That is what lets the step counts stay low enough for a GTX 1650 while the result still holds up in a screenshot.

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Lighting

• Contact-hardening shadows (PCSS). A blocker search sets the penumbra width, then a Vogel-disk PCF whose radius follows it. The penumbra is derived from a real angular light size, so shadows sharpen at the point of contact and spread out with distance the way they actually do.
• Coloured shadows through stained glass and water.
• Global illumination — analytic sky and ground bounce weighted by the surface normal, with an optional screen-space bounce on top.
• Ambient occlusion sharing its sample positions and depth fetch with GI, so the second effect costs one extra tap rather than a whole new loop.
• Subsurface scattering — two lobes, so leaves glow when you look at a canopy against the sun and never go black on their shaded side.
• Block light remapped from Minecraft's linear ramp to an inverse-square falloff with a colour temperature. Held torches light the world.

Sky and atmosphere

• Analytic single-scattering Rayleigh/Mie atmosphere with an ozone layer and a proper Preetham air mass. No LUTs, no loops.
• Warm directional sunlight that shifts from amber at noon to deep orange at sunset, and reaches exactly zero below the horizon.
• A large, warm moon with a real phase terminator, limb darkening and mare detail — casting cold light, because that is how a dark-adapted eye reads moonlight.
• Procedural stars, and a lens flare that only appears when you actually look towards the sun.

Clouds and volumetrics

• Raymarched volumetric clouds with a Beer-Powder light integral, rendered at half resolution. A nearly free cirrus layer on top.
• Volumetric light at half or quarter resolution with temporal reprojection. Extinction is computed analytically at full resolution instead, which is what stops the low-res buffer producing halos along geometry edges.
• God rays through forest canopies, shafts in caves, glow around lava, and beams under water.

Water

• Analytic wave height field — normals come from finite differences of the same function, so there is no normal-map fetch and no tangent-space round trip.
• Fresnel-driven transparency: see the bottom looking down, a mirror at a grazing angle.
• Screen-space refraction, Beer-Lambert absorption measured from the real water column depth, and caustics derived from the divergence of the wave gradient.
• Underwater: wavelength-dependent extinction, light shafts through the surface, and a gentle screen refraction.

Dimensions

• Overworld — soft height fog, ground mist at dawn and in rain, aerial perspective on distant terrain.
• Nether — volumetric haze with a palette derived from the game's own fog colour, so crimson, warped, soul sand valley and basalt deltas each get their own mood instead of one flat red. A height gradient keeps the sense of depth through the murk.
• The End — deep space sky, a procedural nebula built from two competing pigments rather than a purple filter, three parallax star layers, and end stone with a faint glow of its own.

Resource pack materials

LabPBR 1.3 is supported: normals, AO, smoothness, F0 / metal index, porosity, subsurface scattering and emission. Where a resource pack does not ship a map, the shader falls back to its own block-id heuristics — vanilla and PBR resource packs coexist in the same world.

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Presets

Preset	For
Potato	Maximum framerate. 512 shadows, no volumetrics, no clouds, no reflections.
Low	Steady 60+ on weak hardware. 1024 shadows, quarter-res volumetrics.
Medium	Recommended. 1536 shadows with PCSS, half-res volumetrics with temporal reprojection, volumetric clouds, SSR, caustics.
High	2048 shadows, screen-space GI, long SSR rays.
Ultra	3072 shadows, maximum sample counts everywhere.

Around 90 individual settings behind those, grouped into fourteen screens, with English and Russian translations.

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Requirements

• Iris 1.7+, Minecraft 1.21.x (developed and tested on 1.21.10)
• OpenGL 3.3 core
• Not compatible with OptiFine — the pack uses Iris-specific features (RENDERTARGETS, per-buffer blend control, dimension folders).

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Honest limitations

I would rather you know these up front than find them yourself.

• The shadow "cascades" are analytic, not real cascades. Iris gives one shadow pass, therefore one projection. Instead of three real slices, the map is distorted so texel density follows an inverse-distance curve, with bias and filter width tuned separately for three zones. The texel distribution is close to a three-slice CSM. It is not a CSM.
• GI, AO and reflections are screen space. What is not on screen does not contribute. Reflections have a proper sky fallback; GI simply has no off-screen term.
• Local light scattering in the volumetrics is screen space too. Lava you can see glows into the haze; lava behind you does not.
• No parallax occlusion mapping. The LabPBR height channel is decoded and ignored. POM needs a per-fragment march through a height map, which is exactly the cost this pack exists to avoid.
• TAA is not cosmetic here, it is the denoiser for the whole pipeline. Turning it off will make shadows, AO, GI, SSR and the volumetrics visibly noisy. That is the trade the pack is built around.

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Русский

Реалистичный кинематографичный шейдерпак для Iris, собранный вокруг одного правила: выглядеть дорого, работать дёшево.

Никакого path tracing и ray tracing в полном разрешении. Всё стохастическое — тени, AO, глобальное освещение, отражения, волюметрика — намеренно недосэмплировано, раздизерено разным паттерном каждый кадр и вычищается TAA. Именно это позволяет держать низкие счётчики шагов на уровне GTX 1650.

Основное: контактные тени PCSS с настоящим угловым размером источника, цветные тени сквозь витражи и воду, аналитическая атмосфера Рэлея-Ми, тёплое солнце и холодная луна с фазовым терминатором, объёмные облака и volumetric light в половинном разрешении с временной репроекцией, вода с преломлением, поглощением и каустикой, отдельные настроения для биомов Незера и процедурное небо Энда. Поддержан LabPBR 1.3.

Пять пресетов от Potato до Ultra, около 90 настроек на четырнадцати экранах, интерфейс на русском и английском.

Требуется Iris 1.7+, Minecraft 1.21.x. С OptiFine несовместим.

Ограничения честно перечислены в английской секции выше — если коротко: каскады теней аналитические, а не настоящие; GI, AO и отражения экранные; POM нет; без TAA будет шумно.