RDC Analyst

Analyze GPU frame captures to reconstruct render pass graphs, resource flows, and engine structure. This skill handles analysis and knowledge-building requests; for defect debugging, use the debugger framework instead.

Workflow

Step 1: Identify the Input

Determine what capture data is available:

| Input Type | Examples | Action | |------------|----------|--------| | RenderDoc capture | .rdc file, texture/buffer viewer output | Proceed with pass-level analysis | | Frame debugger log | PIX capture, Xcode GPU trace, NVIDIA Nsight export | Proceed — normalize to pass/draw-call model | | Engine replay data | Unreal Insights, Unity Frame Debugger dump | Proceed — map to render pass abstraction | | Text description only | "We have 3 passes: shadow, gbuffer, lighting" | Proceed with user-provided structure | | No capture available | User has no data yet | Help user plan what to capture and with which tool |

Step 2: Clarify the Analysis Goal

Ask the user to confirm what they need. If unclear, ask explicitly:

1. What is the capture or input? (file type, engine, API — D3D12, Vulkan, Metal, etc.)
2. What analysis product do you need?
   • Pass graph (render pass sequence with dependencies)
   • Resource dependency chain (which textures/buffers flow between passes)
   • Material/shader structure map (bindings, permutations, parameter sources)
   • Pipeline state summary (blend modes, rasterizer config per draw)
   • Knowledge entry (reusable reference doc for this rendering technique)
3. What scope? Full frame, a specific pass range, or a single draw call?

Step 3: Perform the Analysis

Follow the appropriate path based on the requested product:

Pass graph reconstruction:

1. List all render passes in execution order
2. For each pass, record: name/label, render targets, input resources, draw count
3. Identify dependencies (pass B reads a resource written by pass A)
4. Output as a structured table or diagram description

Resource dependency chain:

1. Enumerate key resources (render targets, depth buffers, UAVs)
2. Track producer and consumer passes for each resource
3. Flag resources that are written but never read (potential waste)

Material/shader analysis:

1. Group draw calls by pipeline state object or shader combination
2. Identify material parameter sources (constant buffers, push constants)
3. Note shader permutation patterns and binding slot conventions

Knowledge entry:

1. Synthesize findings into a reusable reference document
2. Include: technique name, pass sequence, resource flow, shader roles, key parameters
3. Format for storage in analyzer/common/ as a knowledge artifact

Step 4: Validate and Deliver

Before delivering results:

• [ ] Every claim references a specific pass, draw call, or resource by name/index
• [ ] Dependencies are directional (producer -> consumer) and acyclic where expected
• [ ] Output format matches what the user requested
• [ ] Scope matches what was agreed in Step 2

Routing Table

| User Says | Route To | |-----------|----------| | "Why is this triangle wrong" / "rendering bug" / "visual glitch" | Debugger — this is a defect, not analysis | | "Map out the render passes" / "show me the pass graph" | This skill — pass graph reconstruction | | "What resources does the shadow pass use" | This skill — resource dependency chain | | "How does this engine set up materials" | This skill — material/shader analysis | | "Document this rendering technique" | This skill — knowledge entry |

Example

User: "I have a RenderDoc capture of our deferred renderer. Can you map out the pass structure and resource flow?"

Intake response:

To map the pass structure, I need to confirm:

1. API: Which graphics API — D3D12, Vulkan, or Metal?
2. Scope: Full frame, or a specific section (e.g., just the lighting passes)?
3. Output: Pass graph with resource dependencies, or also material/shader breakdown?

Once confirmed, I will reconstruct the pass sequence, identify render targets and input resources per pass, and produce a dependency table showing resource flow across passes.

After intake — sample output structure:

| Pass | Render Targets | Input Resources | Draw Calls | |------|---------------|-----------------|------------| | Shadow Depth | ShadowMap (D32) | — | 142 | | GBuffer | Albedo, Normal, Depth | — | 387 | | SSAO | AO (R8) | Depth, Normal | 1 | | Lighting | HDR Color | Albedo, Normal, Depth, AO, ShadowMap | 1 | | Tonemap | Backbuffer | HDR Color | 1 |

Current Scope

This skill is part of the incubating analyzer framework. It provides the full intake-and-analysis workflow described above. Analysis artifacts are stored under analyzer/common/. As the framework matures, additional automation (template hooks, runtime contracts) will be added.