Unity Mobile Shader

Toon/Cel Shading

• Stylized games, anime aesthetics
• Banded lighting, outline support
• See references/urp-patterns.md or references/builtin-patterns.md

PBR-Lite

• Realistic look with mobile constraints
• Simplified metallic/smoothness workflow
• See references/urp-patterns.md or references/builtin-patterns.md

Vertex Lit

• Large environments, terrain
• Per-vertex lighting for performance
• See references/urp-patterns.md

Core Optimization Rules

MUST follow these rules for ALL mobile shaders:

Precision

// Use lowest precision possible
half4 color;      // Prefer half (16-bit) for colors
fixed4 mask;      // Use fixed (11-bit) for 0-1 values (Built-in only)
float2 uv;        // float only for UVs and positions

Texture Sampling

• Maximum 4 texture samples per pass
• Use texture atlases to reduce samples
• Combine masks into single RGBA texture (R=metallic, G=AO, A=smoothness)
• Avoid dependent texture reads

Math Operations

// AVOID                    // PREFER
pow(x, 5.0)                 x * x * x * x * x
sin(), cos()                Lookup textures or approximations
normalize() in fragment     Normalize in vertex, pass as varying
length()                    dot(v, v) when comparing distances

Branching

// AVOID dynamic branches
if (condition) { ... }

// PREFER
result = lerp(valueA, valueB, step(threshold, value));

Varying Count

• Maximum 8 interpolators for broad compatibility
• Pack data: float4 uvAndFog instead of separate float2 uv; float2 fog;

Alpha & Transparency

// AVOID alpha testing (clip/discard) - breaks early-Z
clip(alpha - 0.5);

// PREFER alpha blending or opaque
Blend SrcAlpha OneMinusSrcAlpha

Detailed References

• Full optimization rules: references/optimization-rules.md
• URP shader patterns: references/urp-patterns.md
• Built-in shader patterns: references/builtin-patterns.md

Output Checklist

Before delivering shader, verify:

• Correct precision qualifiers used
• Texture samples ≤ 4
• No unnecessary branches
• Varyings ≤ 8
• Fallback shader specified
• LOD levels if complex
• GPU Instancing support if applicable
• SRP Batcher compatible (URP)