vvvv-troubleshooting

Name: vvvv-troubleshooting
Author: tebjan

67installs5forks

How to install vvvv-troubleshooting?

tebjan/vvvv-skills/vvvv-troubleshooting

$npx -y skills add tebjan/vvvv-skills --skill vvvv-troubleshooting

Installs into the current project.

Summary

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.

Files · 1

View on GitHub

SKILL.md

1	# vvvv gamma Troubleshooting
2
3	## C# / ProcessNode Issues
4
5	### "Node" Suffix in Class Name
6
7	Symptom: Node works but has ugly name in vvvv.
8	Fix: Remove "Node" suffix — vvvv convention forbids it.
9
10	```csharp
11	// WRONG
12	[ProcessNode]
13	public class SteeringBehaviorNode { }
14
15	// CORRECT
16	[ProcessNode]
17	public class SteeringBehavior { }
18	```
19
20	### Out Parameters After Inputs
21
22	Symptom: Pins appear in wrong order or node doesn't compile correctly.
23	Fix: `out` parameters must come FIRST in Update signature.
24
25	```csharp
26	// WRONG
27	public void Update(float input = 0f, out float result) { ... }
28
29	// CORRECT
30	public void Update(out float result, float input = 0f) { ... }
31	```
32
33	### Node Not Appearing in Node Browser
34
35	Symptom: Your C# class exists but doesn't show up in vvvv.
36	Fix: Check these in order:
37	1. `[assembly: ImportAsIs]` attribute exists in your project
38	2. `[ProcessNode]` attribute on the class
39	3. Project targets `net8.0`
40	4. DLL is in the correct `lib/net8.0/` path relative to `.vl` document
41	5. Project builds without errors
42
43	### Allocations Causing Frame Drops
44
45	Symptom: GC spikes, stuttering, frame drops.
46	Diagnosis: Allocations in the Update loop.
47
48	Common culprits:
49	- `new` keyword in Update method
50	- LINQ operators (`.Where()`, `.Select()`, `.ToList()`)
51	- String concatenation (`+` operator on strings)
52	- Boxing value types (passing `int` where `object` expected)
53
54	Fix: Cache everything, pre-allocate buffers, eliminate LINQ from hot paths.
55
56	### Missing Change Detection
57
58	Symptom: CPU usage high even when nothing changes.
59	Fix: Compare inputs to cached values, only recompute on change.
60
61	```csharp
62	if (param != _lastParam)
63	{
64	_cached = Compute(param);
65	_lastParam = param;
66	}
67	result = _cached; // Always output cached
68	```
69
70	### Downstream Nodes See null/default
71
72	Symptom: Connected nodes get no data, even though the node "works".
73	Fix: Always output cached result, even when no computation happens.
74
75	```csharp
76	// WRONG — output is only set inside the if block
77	public void Update(out float result, float input = 0f)
78	{
79	if (input != _last)
80	{
81	result = Compute(input);
82	_last = input;
83	}
84	// result is unassigned when input hasn't changed!
85	}
86
87	// CORRECT — always assign output
88	public void Update(out float result, float input = 0f)
89	{
90	if (input != _last)
91	{
92	_cached = Compute(input);
93	_last = input;
94	}
95	result = _cached;
96	}
97	```
98
99	## SDSL Shader Issues
100
101	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.
102
103	## Runtime Issues
104
105	### Memory Leaks
106
107	Symptom: Memory usage grows over time.
108	Causes:
109	- Missing `IDisposable` on nodes with native resources
110	- COM objects (`ComPtr<T>`) not disposed
111	- Event handler subscriptions not unsubscribed
112
113	### Thread Safety
114
115	Symptom: Intermittent crashes, data corruption.
116	Fix: `Update()` runs on the main thread. Capture `SynchronizationContext` in the constructor, then marshal background results back:
117
118	```csharp
119	private SynchronizationContext _vlSyncContext;
120
121	public MyNode()
122	{
123	_vlSyncContext = SynchronizationContext.Current!;
124	}
125
126	// From background thread:
127	_vlSyncContext.Post(_ => { /* runs on VL thread */ }, null);
128	```
129
130	### Circular Dependencies
131
132	Symptom: vvvv warns about circular dependency, patch won't compile.
133	Fix: Insert a `FrameDelay` node to break the cycle.
134
135	## Build Issues
136
137	### Target Framework Mismatch
138
139	Symptom: DLL loads but types aren't found.
140	Fix: Ensure `.csproj` targets `net8.0` (matching vvvv gamma's runtime).
141
142	### Assembly Version Conflicts
143
144	Symptom: `FileLoadException` or `TypeLoadException` at runtime.
145	Fix: Align package versions with vvvv's bundled versions. Check vvvv's `lib/` folder for reference.
146
147	For detailed error-to-solution mapping, see [error-catalog.md](error-catalog.md).

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6 picks

Type

vvvv-troubleshooting

67installs5forks

View on GitHub

How to install vvvv-troubleshooting?

tebjan/vvvv-skills/vvvv-troubleshooting

$npx -y skills add tebjan/vvvv-skills --skill vvvv-troubleshooting

Installs into the current project.

Summary

Files · 1

View on GitHub

SKILL.md

1	# vvvv gamma Troubleshooting
2
3	## C# / ProcessNode Issues
4
5	### "Node" Suffix in Class Name
6
7	Symptom: Node works but has ugly name in vvvv.
8	Fix: Remove "Node" suffix — vvvv convention forbids it.
9
10	```csharp
11	// WRONG
12	[ProcessNode]
13	public class SteeringBehaviorNode { }
14
15	// CORRECT
16	[ProcessNode]
17	public class SteeringBehavior { }
18	```
19
20	### Out Parameters After Inputs
21
22	Symptom: Pins appear in wrong order or node doesn't compile correctly.
23	Fix: `out` parameters must come FIRST in Update signature.
24
25	```csharp
26	// WRONG
27	public void Update(float input = 0f, out float result) { ... }
28
29	// CORRECT
30	public void Update(out float result, float input = 0f) { ... }
31	```
32
33	### Node Not Appearing in Node Browser
34
35	Symptom: Your C# class exists but doesn't show up in vvvv.
36	Fix: Check these in order:
37	1. `[assembly: ImportAsIs]` attribute exists in your project
38	2. `[ProcessNode]` attribute on the class
39	3. Project targets `net8.0`
40	4. DLL is in the correct `lib/net8.0/` path relative to `.vl` document
41	5. Project builds without errors
42
43	### Allocations Causing Frame Drops
44
45	Symptom: GC spikes, stuttering, frame drops.
46	Diagnosis: Allocations in the Update loop.
47
48	Common culprits:
49	- `new` keyword in Update method
50	- LINQ operators (`.Where()`, `.Select()`, `.ToList()`)
51	- String concatenation (`+` operator on strings)
52	- Boxing value types (passing `int` where `object` expected)
53
54	Fix: Cache everything, pre-allocate buffers, eliminate LINQ from hot paths.
55
56	### Missing Change Detection
57
58	Symptom: CPU usage high even when nothing changes.
59	Fix: Compare inputs to cached values, only recompute on change.
60
61	```csharp
62	if (param != _lastParam)
63	{
64	_cached = Compute(param);
65	_lastParam = param;
66	}
67	result = _cached; // Always output cached
68	```
69
70	### Downstream Nodes See null/default
71
72	Symptom: Connected nodes get no data, even though the node "works".
73	Fix: Always output cached result, even when no computation happens.
74
75	```csharp
76	// WRONG — output is only set inside the if block
77	public void Update(out float result, float input = 0f)
78	{
79	if (input != _last)
80	{
81	result = Compute(input);
82	_last = input;
83	}
84	// result is unassigned when input hasn't changed!
85	}
86
87	// CORRECT — always assign output
88	public void Update(out float result, float input = 0f)
89	{
90	if (input != _last)
91	{
92	_cached = Compute(input);
93	_last = input;
94	}
95	result = _cached;
96	}
97	```
98
99	## SDSL Shader Issues
100
101	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.
102
103	## Runtime Issues
104
105	### Memory Leaks
106
107	Symptom: Memory usage grows over time.
108	Causes:
109	- Missing `IDisposable` on nodes with native resources
110	- COM objects (`ComPtr<T>`) not disposed
111	- Event handler subscriptions not unsubscribed
112
113	### Thread Safety
114
115	Symptom: Intermittent crashes, data corruption.
116	Fix: `Update()` runs on the main thread. Capture `SynchronizationContext` in the constructor, then marshal background results back:
117
118	```csharp
119	private SynchronizationContext _vlSyncContext;
120
121	public MyNode()
122	{
123	_vlSyncContext = SynchronizationContext.Current!;
124	}
125
126	// From background thread:
127	_vlSyncContext.Post(_ => { /* runs on VL thread */ }, null);
128	```
129
130	### Circular Dependencies
131
132	Symptom: vvvv warns about circular dependency, patch won't compile.
133	Fix: Insert a `FrameDelay` node to break the cycle.
134
135	## Build Issues
136
137	### Target Framework Mismatch
138
139	Symptom: DLL loads but types aren't found.
140	Fix: Ensure `.csproj` targets `net8.0` (matching vvvv gamma's runtime).
141
142	### Assembly Version Conflicts
143
144	Symptom: `FileLoadException` or `TypeLoadException` at runtime.
145	Fix: Align package versions with vvvv's bundled versions. Check vvvv's `lib/` folder for reference.
146
147	For detailed error-to-solution mapping, see [error-catalog.md](error-catalog.md).

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6 picks

Type