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Compositor Node "Filter" Outputs clear image
Closed, ResolvedPublic

Description

System Information
intel x980, 34gb ram
Win7 64bit
nvidia gtx 750ti
nvidia gtx 480

Blender Version
2.77 Release Candidate [da81227]
2.74
2.69
Worked: (optional)

Short description of error

"Laplace" in the Compositor node "Filter" Outputs just a plain (Alpha = 0) Image.
Either I do something wrong, or the bug is quite old. (Tested with 2.69, 2.74 and 2.77RC )

Exact steps for others to reproduce the error
Just hit render in this file.

Let me know if I'm wrong ;)

Event Timeline

A #b3d mate reported similar behaviour but he hat a single pixel line on the borders of his rendering. (Waiting for his screenshot)

Inte i7 5829K, 16gb ram
Win7 64bit
R9 380 Nitro (old Catalyst driver)

Blender 2.76b

Kévin Dietrich (kevindietrich) triaged this task as Confirmed, Medium priority.

This happens because for some obscure reasons the convolution operation is overwriting the input's alpha.

Looked into this, and seems theres no bug, it just so happens that the *Laplace* filter is always zeroing out alpha (where all alpha pixels are 1.0, the result is 0.0). Just as entirely white input gives black output.

So fix here would be to add an Alpha toggle for this node. (We could have RGB and Alpha) as some other nodes do.

Hi Campbell,

I would highly apprechiate an Alpha toggle, so that it is clear for users what happens more over, I would show that it actually can do something with the Alpha :)
But on the other hand: It's pretty simple to split RGB and Alpha, or just Overwrite the Alpha after the laplace operation.

Thank you for your time!