Skill: tebjan/vvvv-patching (version 1.0.0)

--- name: vvvv-patching description: Explains vvvv gamma visual programming patterns — dataflow, node connections, regions (ForEach/If/Switch/Repeat/Accumulator), channels for reactive data flow, event handling (Bang/Toggle/FrameDelay/Changed), patch organization, and common anti-patterns (circular dependencies, polling vs reacting, ignoring Nil). Use when the user asks about patching best practices, dataflow patterns, event handling, or how to structure visual programs. license: CC-BY-SA-4.0 compatibility: Designed for coding AI agents assisting with vvvv gamma development metadata: author: Tebjan Halm version: "1.0" --- # vvvv Patching Patterns ## Dataflow Basics - **Left-to-right, top-to-bottom** execution order - **Links** carry data between pads (input/output connection points) - **Spreading** — connecting a `Spread<T>` to a single-value input auto-iterates the node - Every frame, the entire connected graph evaluates; disconnected subgraphs are skipped Both visual patches and C# source projects operate in a live environment — edits take effect immediately while the program runs. Patch changes preserve node state; C# code changes trigger a node restart (Dispose → Constructor). You can adjust parameters, add connections, and restructure patches while seeing results in real-time. ## When to Patch vs Write C# | Patch | Code (C#) | |---|---| | Data flow routing, visual connections | Performance-critical algorithms | | Prototyping and parameter tweaking | Complex state machines | | UI composition and layout | .NET library interop | | Simple transformations | Native resource management | As a rule: **patch the data flow, code the algorithms**. ## Regions Regions are visual constructs that control execution flow: | Region | Purpose | C# Equivalent | |---|---|---| | **ForEach** | Iterate over Spread elements | `foreach` loop | | **If** | Conditional execution | `if/else` | | **Switch** | Multi-branch selection | `switch` | | **Repeat** | Loop N times | `for` loop | | **Accumulator** | Running aggregation | `Aggregate/Fold` | ## Process Nodes in Patches Process nodes are the primary way to add state to patches: - They have a **Create** region (runs once) and an **Update** region (runs each frame) - Internal state persists between frames - Can contain sub-patches for complex logic ## Channels — Reactive Data Flow Channels provide two-way data binding: - `IChannel<T>` — observable value container - `.Value` — read or write the current value - Channels persist state across sessions - Connect channels between nodes for reactive updates without explicit links ## Event Handling - **Bang** — a one-frame `true` pulse (trigger) - **Toggle** — alternates between `true` and `false` - **FrameDelay** — delays a value by one frame (breaks circular dependencies) - Use `Changed` node to detect when a value changes between frames ## Patch Organization ### Naming Conventions - Use PascalCase for patch names and node names - Group related operations under a common category - Use descriptive names that indicate the operation (verb + noun) ### Structure - Keep patches focused — one purpose per patch - Extract reusable logic into sub-patches - Use **IOBox** nodes for exposing parameters - Add **Pad** nodes to create input/output pins on the patch boundary ## Common Anti-Patterns 1. **Circular dependencies** — use FrameDelay to break cycles 2. **Too many nodes in one patch** — extract sub-patches 3. **Polling instead of reacting** — use Channels for reactive updates 4. **Ignoring Nil** — always handle null/empty Spread inputs gracefully For common patterns reference, see [patterns.md](patterns.md).


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