What does HRESULT 0x8899002D (D2DERR_TOO_MANY_TRANSFORM_INPUTS) mean?

D2DERR_TOO_MANY_TRANSFORM_INPUTS

The scope of D2DERR_TOO_MANY_TRANSFORM_INPUTS is Direct2D custom-effect transform graphs. A custom effect attempted to use a transform node with more inputs than Direct2D permits. Keep 0x8899002D beside the returning method because a wrapper can replace this distinction with a generic subsystem message.

Misleading responses

TOO_MANY_SHADER_ELEMENTS concerns shader complexity; TOO_MANY_TRANSFORM_INPUTS concerns graph node arity. Do not respond with a universal render-target recreation loop unless the returned status specifically documents device-loss recovery; graph, property, numeric, lifetime, and print-state errors require correcting their contract.

Locate the first rejecting layer

A transform graph must have valid node identities, supported input counts, complete input mappings, one reachable output, and no cycles. Public graph configuration errors usually point to caller construction; an internal graph error warrants preserving a minimal valid-looking graph and runtime evidence rather than inventing a missing public rule.

ID2D1TransformNode input count and graph connections.

Evidence to preserve

• Transform node type and GetInputCount result
• Number of connected edges
• Effect input count and graph mapping
• Custom effect Initialize sequence

Controlled reproduction

Build one pass-through node, validate it, and add one node or edge per step. Log input count, edge endpoints, effect-input mapping, output selection, and topological order before committing the graph.

1. Reduce the node to documented input count.
2. Combine sources in staged nodes.
3. Validate counts before AddNode and ConnectNode.
4. Use a pass-through graph as baseline.

Technical references

• Microsoft: Direct2D error codes.
• Microsoft: Direct2D custom effects.
• Microsoft: ID2D1TransformGraph.
• Microsoft: Direct2D effect properties.