shader-flag-protocol

name	shader-flag-protocol
description	Work with the packed ShaderFlag protocol used by NBShaders, NBShaders2, and related FX systems. Use when adding, debugging, migrating, or reviewing bit-packed shader flags, wrap flags, UV mode packing, custom data packing, color channel packing, foldout flags, or MaterialPropertyBlock flag writes.

Shader Flag Protocol

Use this skill whenever a task touches the packed ShaderFlag mechanism.

This project treats ShaderFlags as a cross-layer protocol, not a local implementation detail.

Read These Files First

• Packages/NB_FX/XuanXuanRenderUtility/Runtime/ShaderFlagsBase.cs
• Packages/NB_FX/NBShaders/Runtime/W9ParticleShaderFlags.cs
• Packages/NB_FX/NBShaders/Shader/HLSL/EffectFlags.hlsl

Read these too when relevant:

• Packages/NB_FX/NBShaders/Shader/HLSL/ParticlesUnlitInputNew.hlsl
• Packages/NB_FX/NBShaders/Editor/ParticleBaseGUI.cs
• Packages/NB_FX/XuanXuanRenderUtility/Editor/ShaderGUIHelper.cs
• Packages/NB_FX/NBShaders2/Shader/NBShader.shader
• Packages/NB_FX/NBShaders2/Editor/NBShaderGUI.cs

Core Rule

Do not treat a ShaderFlag change as a single-file edit.

Any meaningful change may require synchronized updates across:

1. C# flag definitions
2. shader property declarations and defaults
3. HLSL macro definitions and decoding logic
4. editor GUI read/write logic
5. runtime Material or MaterialPropertyBlock writes
6. existing serialized materials and compatibility assumptions

What Counts As Protocol State

In this project, packed state includes more than feature toggles.

It also includes:

• main feature bits
• secondary feature bits
• wrap-mode encoding
• foldout persistence bits
• color channel selection
• UV mode selection
• custom data source mapping
• procedural-noise blend mode selection

Required Investigation Flow

When changing or debugging a flag-related issue:

1. Identify which packed storage slot is affected.
2. Find the C# constant or constants involved.
3. Find the matching HLSL macro or decode path.
4. Find the shader property name and default value.
5. Find all GUI or runtime writers of that state.
6. Check whether old materials depend on the current bit layout.
7. Apply the smallest safe change.

Slot Mapping to Keep in Mind

For W9ParticleShaderFlags, the packed indices currently map to:

• 0: _W9ParticleShaderFlags
• 1: _W9ParticleShaderFlags1
• 2: _W9ParticleShaderWrapFlags
• 3: _W9ParticleShaderGUIFoldToggle
• 4: _W9ParticleShaderGUIFoldToggle1
• 5: _W9ParticleShaderGUIFoldToggle2
• 6: _W9ParticleShaderColorChannelFlag
• 7: _W9ParticleShaderPNoiseBlendFlag

Do not change slot meaning casually.

Special Cases

Foldout Bits

Foldout bits are persisted material state and are also used by editor animation logic.

If you touch foldout bits, verify:

• W9ParticleShaderFlags bit constants
• ShaderGUIHelper foldout readers/writers
• any assumptions tied to anim-bool indexing

Wrap Flags

Wrap mode is packed into _W9ParticleShaderWrapFlags and decoded in HLSL through bit pairs.

If you touch wrap behavior, verify both:

• C# write path
• CheckLocalWrapFlags behavior in HLSL

Custom Data Packing

Custom data routing is nibble-packed and decoded in HLSL.

If you touch custom data mapping, verify both:

• C# flag position constants
• GetCustomData in HLSL

UV Mode Packing

UV mode is packed and then decoded by GetUVByUVMode.

If you touch UV mode behavior, verify:

• editor write path
• packed bit positions
• HLSL decoder behavior

PNoise Blend Packing

Blend mode is packed and decoded by BlendPNoise.

If you change available blend modes or bit layout, update both sides together.

Do Not Do These

• do not replace the protocol with scattered booleans
• do not move existing bits without checking compatibility impact
• do not update only C# or only HLSL
• do not assume a flag is editor-only without checking shader reads
• do not add a new packed meaning if there is already an existing compatible slot or pattern

Output Expectations

When reporting or implementing a change, explicitly state:

• which packed slot was involved
• which bit or encoded field was involved
• which files were updated or verified
• whether compatibility with existing materials was preserved