Reviewing Platform Abstraction

Table of Contents

• [Core Principle](#core-principle)
• [Quick Reference](#quick-reference)
• [Architecture Overview](#architecture-overview)
• [When to Use This Skill](#when-to-use-this-skill)
• [Review Checklist](#review-checklist)
• [Key Violations to Check](#key-violations-to-check)
• [Abstraction Interfaces](#abstraction-interfaces)
• [Platform Code Locations](#platform-code-locations)
• [Adding New Rendering Backend](#adding-new-rendering-backend)
• [Validating Abstraction Compliance](#validating-abstraction-compliance)
• [Review Output Format](#review-output-format)

Core Principle

All platform-specific code must live in Engine/Platform/{PlatformName}/

Quick Reference

✅ Engine code should:

• Use IRendererAPI, IShader, ITexture2D interfaces
• Inject dependencies via constructors
• Never import Silk.NET.* namespaces
• Never instantiate platform types directly

✅ Platform code should:

• Live in Engine/Platform/SilkNet/
• Implement abstraction interfaces
• Use SilkNetContext.GL for OpenGL
• Call GLDebug.CheckError() after GL calls

❌ Never:

• Import Silk.NET.OpenGL in Engine namespace
• Use concrete types like SilkNetShader in engine code
• Put OpenGL code outside Platform/SilkNet
• Add graphics features without interface abstraction

Architecture Overview

Engine Core (Platform-Agnostic)
    ↓ Uses interfaces only
Abstraction Layer (IRendererAPI, IShader, ITexture2D, etc.)
    ↓ Implemented by
Platform Implementation (Engine/Platform/SilkNet/)

Current: OpenGL via Silk.NET Future: Vulkan, DirectX, Metal, WebGL

When to Use This Skill

Invoke this skill when:

• Reviewing rendering/graphics PRs - Check for platform abstraction violations before merge
• Adding new graphics features - Ensure compute shaders, geometry shaders, or advanced rendering features use proper abstraction
• Investigating rendering bugs - Determine if issues are platform-specific due to leaky abstractions
• Architecture audits - Validate that engine core remains platform-agnostic
• Refactoring graphics code - Ensure changes maintain abstraction boundaries
• Planning new rendering backend - Understand requirements for adding Vulkan, DirectX, Metal, or WebGL support

Review Checklist

Run these commands to detect violations automatically:

1. Check for direct Silk.NET imports in engine code

grep -r "using Silk\.NET\." Engine/ --exclude-dir=Platform

Expected: No matches outside Engine/Platform/

2. Find concrete platform types in engine code

grep -rE "SilkNet[A-Z]" Engine/ --exclude-dir=Platform | grep -E "(private|public|protected)"

Expected: No SilkNetShader, SilkNetTexture2D, etc. in engine code

3. Verify interface usage in core rendering

Check Engine/Renderer/Graphics2D.cs and Engine/Renderer/Graphics3D.cs:

• All fields use interface types (IRendererAPI, IShader, ITexture2D, etc.)
• No direct GL calls or OpenGL imports

4. Validate new graphics features

For any new rendering features, verify:

• Interface exists in Engine/Renderer/ or Engine/Core/?
• Implementation in Engine/Platform/SilkNet/?
• Factory registered in Program.cs DI container?

Key Violations to Check

Detailed Example: Adding New Graphics Features

When adding graphics features (compute shaders, geometry shaders, etc.), always create interface first:

// 1. Interface in Engine/Renderer/
public interface IComputeShader : IDisposable {
    void Dispatch(uint x, uint y, uint z);
}

// 2. Implementation in Engine/Platform/SilkNet/
public class SilkNetComputeShader : IComputeShader { ... }

// 3. Factory for creation
public interface IComputeShaderFactory {
    IComputeShader Create(string path);
}

// 4. Engine uses interface
public ParticleSystem(IComputeShaderFactory factory) {
    _compute = factory.Create("particles.comp");
}

Abstraction Interfaces

Core Interfaces (must use in engine code):

• IRendererAPI - Draw commands, clear, viewport
• IShader - Shader programs
• ITexture2D - Texture resources
• IVertexArray - Vertex array objects
• IFrameBuffer - Render targets
• IVertexBuffer, IIndexBuffer - Vertex/index data

Platform Implementations (only in Platform/SilkNet):

• All live in Engine/Platform/SilkNet/
• Use SilkNetContext.GL for OpenGL access
• Call GLDebug.CheckError() after GL calls

Platform Code Locations

Engine/Platform/SilkNet/
├── SilkNetRendererApi.cs      # IRendererAPI
├── SilkNetShader.cs           # IShader
├── SilkNetTexture2D.cs        # ITexture2D
├── SilkNetVertexArray.cs      # IVertexArray
├── Buffers/
│   ├── SilkNetFrameBuffer.cs
│   ├── SilkNetVertexBuffer.cs
│   └── SilkNetIndexBuffer.cs
├── Audio/
│   └── SilkNetAudioEngine.cs  # OpenAL
└── Input/
    └── SilkNetInputSystem.cs

Adding New Rendering Backend

1. Create namespace: Engine/Platform/Vulkan/

2. Implement interfaces:

public class VulkanRendererApi : IRendererAPI { ... }
public class VulkanShader : IShader { ... }
// etc.

3. Update DI registration:

// Program.cs
switch (backend) {
    case "OpenGL":
        container.Register<IRendererAPI, SilkNetRendererApi>();
        break;
    case "Vulkan":
        container.Register<IRendererAPI, VulkanRendererApi>();
        break;
}

4. No engine code changes needed - already uses interfaces!

Validating Abstraction Compliance

After fixing violations or adding new features, validate compliance:

1. Build Test

dotnet build

Expected: Build succeeds without errors

2. Automated Violation Check

Run grep commands from [Review Checklist](#review-checklist) Expected: No Silk.NET imports or concrete types in engine code

3. Smoke Test

cd Editor && dotnet run

Expected: Editor launches, rendering works correctly

4. Future-Proof Test

Ask: "Could I swap SilkNetRendererApi for VulkanRendererApi without changing engine code?" Expected: Yes - all engine code uses IRendererAPI interfaces

Review Output Format

Issue: [Violation description] Location: [File:Line] Type: [Direct OpenGL / Concrete Type / Wrong Namespace / Missing Interface] Fix:

// Current (wrong)
[bad code]

// Should be (correct)
[fixed code]

Priority: [Critical/High/Medium/Low]