depthNode: the default value of depthNode is invalid

[Lafeu-p]

Description

In the three.js example with a webgpu_instance_points, when enabling logarithmicDepthBuffer, the example encounters the following error.

I noticed that the issue was caused by not setting a value for depthNode. When I set depthNode = depth, the error disappeared. However, I noticed that three.js does have a default depthNode set.

Additionally, although directly setting depthNode = depth eliminates the error, the result is not as expected, as the depth appears to be chaotic.

I noticed that the configuration for depth in the code didn't take effect, and upon debugging the shader, I found that the logarithmic depth-related shader code wasn't being used.

If I modify this line of code to
depth.valueNode = depthNode
then I no longer need to manually set depthNode = node, and the depth behaves as expected. I'm a beginner with NodeMaterial, but I believe this is a bug, and I look forward to further feedback.

Reproduction steps

1.enabling logarithmicDepthBuffer,

Code

logarithmicDepthBuffer = true

Live example

http://localhost:8080/examples/?q=instance#webgpu_instance_points

Screenshots

Version

170dev

Device

Desktop

Browser

Chrome

OS

MacOS

[Mugen87]

The runtime error occurs because the following line fails:

three.js/src/nodes/accessors/ModelViewProjectionNode.js

Line 27 in 3728a0a

return varying( builder.context.mvp );

That happens because builder.context.mvp isn't defined for InstancedPointsNodeMaterial.

[Lafeu-p]

If I customize a material and have both a vertexNode and a fragmentNode, do I need to manually specify builder.context.mvp for each?

[Mugen87]

When I read the code correctly, then you have to define builder.context.mvp when using a custom vertexNode and if you want to use logarithmic depth buffer. ModelViewProjectionNode is the only component which relies on builder.context.mvp and it is used by the logarithmic depth buffer implementation in its fragment part.

@sunag Maybe this bit needs to be revisited since we should not expect builder.context.mvp is correctly set in all instances when a custom vertexNode is used. If builder.context.mvp isn't defined, couldn't ModelViewProjectionNode fallback to the result of vertexNode (which is essentially gl_Position)?

[sunag]

@sunag Maybe this bit needs to be revisited since we should not expect builder.context.mvp is correctly set in all instances when a custom vertexNode is used. If builder.context.mvp isn't defined, couldn't ModelViewProjectionNode fallback to the result of vertexNode (which is essentially gl_Position)?

Yes, this needs a review. When I visited this issue, I also wondered why we don't have a node to create these circles and use them in sprites and thus avoid duplication of code.

[Mugen87]

This issue has been fixed via #30108. webgpu_instance_points now works with logarithmic depth buffer 🎉