Topic: hovering trees in SP2 build3 beta 64bit

[Lech Switala]

I read about the trees hovering 30 cm above the ground in the 64bit version - in my case (SP2 build3 beta 64bit) they hover too, only to touch the ground for the second I press the sun controls, afterwards they hover again.  Has there been a cure found for the hovering ? 

[Remko]

It's a bug we are working on. The trees are also correct in final render.

[Remko]

FINALLY found a solution.

It was an error in Speed tree wind algorithm. As it turns out the amount of wind depends on the height of a vertex.

So, for the trunk there are some vertices with y=0. In the shader there is a line which raises this value to a certain power. Normally raising 0 to the power of 2 should result in 0.

However, in HLSL the compiler implements the pow(0,2) function as: exp(log(0) * 2) which results in NaN causing the polygons with those vertices to disappear.


Will be fixed in next update!

[Lech Switala]

Damn NaN!
Does this mean with no wind the hovering wouldn't happen?

Love your explanation, although I do feel a bit inferior reading it.
The part with 0 to power 2 gives 0 I did understand.   However you lost me in "in HLSL the compiler implements the pow(0,2) function as: exp(log(0) * 2)".

So the trees will stop hovering in the next build or update?

[Remko]

Damn NaN!
Does this mean with no wind the hovering wouldn't happen?

Love your explanation, although I do feel a bit inferior reading it.
The part with 0 to power 2 gives 0 I did understand.   However you lost me in "in HLSL the compiler implements the pow(0,2) function as: exp(log(0) * 2)".

So the trees will stop hovering in the next build or update?

Yes! The next build will have this fixed. Plus all the other bugs we could find and were reported.

[Lech Switala]

Great news!