Diagnoses and fixes common vvvv gamma errors in C# nodes, SDSL shaders, and runtime behavior. Use when encountering errors, exceptions, crashes, red nodes, shader compilation failures, missing nodes in the browser, performance issues, or unexpected behavior.
Symptom: Node works but has ugly name in vvvv. Fix: Remove "Node" suffix — vvvv convention forbids it.
// WRONG
[ProcessNode]
public class SteeringBehaviorNode { }
// CORRECT
[ProcessNode]
public class SteeringBehavior { }
Symptom: Pins appear in wrong order or node doesn't compile correctly.
Fix: out parameters must come FIRST in Update signature.
// WRONG
public void Update(float input = 0f, out float result) { ... }
// CORRECT
public void Update(out float result, float input = 0f) { ... }
Symptom: Your C# class exists but doesn't show up in vvvv. Fix: Check these in order:
[assembly: ImportAsIs] attribute exists in your project[ProcessNode] attribute on the classnet8.0lib/net8.0/ path relative to .vl documentSymptom: GC spikes, stuttering, frame drops. Diagnosis: Allocations in the Update loop.
Common culprits:
new keyword in Update method.Where(), .Select(), .ToList())+ operator on strings)int where object expected)Fix: Cache everything, pre-allocate buffers, eliminate LINQ from hot paths.
Symptom: CPU usage high even when nothing changes. Fix: Compare inputs to cached values, only recompute on change.
if (param != _lastParam)
{
_cached = Compute(param);
_lastParam = param;
}
result = _cached; // Always output cached
Symptom: Connected nodes get no data, even though the node "works". Fix: Always output cached result, even when no computation happens.
// WRONG — output is only set inside the if block
public void Update(out float result, float input = 0f)
{
if (input != _last)
{
result = Compute(input);
_last = input;
}
// result is unassigned when input hasn't changed!
}
// CORRECT — always assign output
public void Update(out float result, float input = 0f)
{
if (input != _last)
{
_cached = Compute(input);
_last = input;
}
result = _cached;
}
For SDSL syntax rules, common mistakes, and correct/wrong examples, consult the vvvv-shaders skill and its syntax-rules.md. Key issues: static const scope, missing semicolons, missing override, enum binding format.
Symptom: Memory usage grows over time. Causes:
IDisposable on nodes with native resourcesComPtr<T>) not disposedSymptom: Intermittent crashes, data corruption.
Fix: Update() runs on the main thread. Capture SynchronizationContext in the constructor, then marshal background results back:
private SynchronizationContext _vlSyncContext;
public MyNode()
{
_vlSyncContext = SynchronizationContext.Current!;
}
// From background thread:
_vlSyncContext.Post(_ => { /* runs on VL thread */ }, null);
Symptom: vvvv warns about circular dependency, patch won't compile.
Fix: Insert a FrameDelay node to break the cycle.
Symptom: DLL loads but types aren't found.
Fix: Ensure .csproj targets net8.0 (matching vvvv gamma's runtime).
Symptom: FileLoadException or TypeLoadException at runtime.
Fix: Align package versions with vvvv's bundled versions. Check vvvv's lib/ folder for reference.
For detailed error-to-solution mapping, see error-catalog.md.