water-fluid-shaders
Water and Fluid Shaders for Mobile Unity
TRIGGER
Use this skill when the user wants to create, modify, or optimize water, ocean, river, lake, pond, fluid, lava, or liquid shaders in Unity — especially for mobile or WebGL. Triggers include: "water shader", "ocean", "waves", "foam", "shoreline", "refraction", "caustics", "Gerstner", "fluid", "depth coloring", "stylized water", "toon water", or references to any water-related visual effect. Also trigger when the user references NVJOB, bmjoy, or Alexander Ameye water shader repos.
CORE RULES — MOBILE WATER CONSTRAINTS
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No tessellation on mobile. Mobile GPUs do not support hardware tessellation efficiently. Use vertex displacement on the existing mesh instead.
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Limit water shader to ≤ 4 texture samples. A typical mobile water shader budget: 1 normal map (tiled, scrolled), 1 depth texture (for shoreline/foam), 1 scene color (for refraction), 1 foam/detail texture. Drop scene color refraction first if over budget.
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Depth Texture and Opaque Texture must be enabled in URP Asset settings for depth-based shoreline detection and refraction. These add a copy pass — budget ~1ms on mobile. If this is too expensive, use vertex-color-based depth instead.
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Use single-layer normals. Desktop water often blends 2-3 normal map samples at different scales. On mobile, use 1 normal map sample with UV scrolling for animation.
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Gerstner waves in vertex shader only. Never compute wave displacement per-fragment. Limit to 2–3 wave octaves on mobile (4+ on desktop).