On Thu, Jan 31, 2013 at 9:05 AM, Vivian Meazza wrote:
>
> I'm not sure if I'm doing something wrong here: we now have so many
> different options, but getting snow by method 2 or 3 results in deciduous
> trees in full leaf with snow coverage on the ground. Not an impossible
> scenario, but bare trees are more likely. Is this a bug?
I'll claim it's a limitation of the current scheme rather than a bug :).
As it happens I've got a fix/enhancements for this sitting on my
computer right now that's just about ready to push, but which I need
to discuss.
Basically, at present the trees are represented by a 512x128 texture
containing 8 trees in row. My enhancement is to change this to a
512x512 texture containing 4 rows or tree, representing summer,
summer+snow, winter and winter+snow.
I then have a small change to the shader (that doesn't use an "if"
test :) ) to shift the texture to the correct row depending on the
snow level and whether we think it's "winter" or not.
We need both snow and winter as separate states as with snow alone
you'd end up with deciduous trees with leaves below the snowline and
bare branches above - acid snow ?
There are a couple of problems I'd like advice on:
1) (pre-existing) Under rembrandt, the winter deciduous tree texture
suffers as it has significant alpha but isn't registered as a
transparent object.
2) It's not clear to me that we want to display trees with snow on
them above the snowline. In my experience, trees very quickly lose
their snow cover after snow-fall if there's any wind. So perhaps the
snow-covered trees should only be used if snow is actually falling,
and what we really need is a simple way to change from summer to
winter tree textures?
3) We use /sim/startup/season to indicate whether it is summer or
winter. That's a string ("summer", "winter") that I need to map into
an integer to pass down the stack to a uniform in the shader. There's
no obvious way to do this mapping, so I'm thinking of changing the
property we currently use (/sim/startup/season) globally to
"/environment/winter" or somesuch, with type integer.
And, to go back to the original point about winter textures I agree
that we need to keep them.
-Stuart
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