Derivative filtering for multires baker

This is an updated version of patch from https://codereview.appspot.com/4837062

Changes comparing to old version:

- Applies on current trunk
- Style cleanup
- Derivative maps baking now possible with both multires and regular bakers

Naming and descriptions in UI could be improved.
Reporting of scale is currently disabled. Not sure how to do reporting best when baking multiple objects. Easiest way would be to report several RPT_INFO. Other ideas are welcome.

[brechtvl, 2013-09-23 15:14:12]

I think RPT_INFO would be the appropriate way to report the scale. We don't
really have a good mechanism for this kind of thing, but it seems the most
logical solution.

Further looks good, except the UI, I would make this another bake type even if
the implementation internally is based on displacement.

[brechtvl, 2013-09-23 15:14:20]

https://codereview.appspot.com/13778045/diff/1/release/scripts/startup/bl_ui/...
File release/scripts/startup/bl_ui/properties_render.py (right):

https://codereview.appspot.com/13778045/diff/1/release/scripts/startup/bl_ui/...
release/scripts/startup/bl_ui/properties_render.py:551: if rd.bake_type ==
'DISPLACEMENT':
Shouldn't this be its own bake type? Not sure why it would be under
displacement.

https://codereview.appspot.com/13778045/diff/1/release/scripts/startup/bl_ui/...
release/scripts/startup/bl_ui/properties_render.py:556: col.prop(rd,
"use_bake_user_scale")
This could be on the same row as the bake user scale, just a checkbox without
text.

[sergey.vfx, 2013-09-24 20:18:11]

On 2013/09/23 15:14:20, brechtvl wrote:
>
https://codereview.appspot.com/13778045/diff/1/release/scripts/startup/bl_ui/...
> File release/scripts/startup/bl_ui/properties_render.py (right):
> 
>
https://codereview.appspot.com/13778045/diff/1/release/scripts/startup/bl_ui/...
> release/scripts/startup/bl_ui/properties_render.py:551: if rd.bake_type ==
> 'DISPLACEMENT':
> Shouldn't this be its own bake type? Not sure why it would be under
> displacement.

Well, historical question. Internally derivatives are being calculated from
displacement map. We could do the following: add "Derivative Map" baker type,
which will internally use displacement baker + derivative filtering and deliver
derivative map to the user.

Does it sound like a good plan?

>
https://codereview.appspot.com/13778045/diff/1/release/scripts/startup/bl_ui/...
> release/scripts/startup/bl_ui/properties_render.py:556: col.prop(rd,
> "use_bake_user_scale")
> This could be on the same row as the bake user scale, just a checkbox without
> text.

Yep, thought this as well. Not big fan of un-labeled checkboxes, but if you
think it'll be more clear this way ot so much fussed to change.

Also, do you think properties descriptions are clear enough?

[brechtvl, 2013-09-24 20:40:44]

On 2013/09/24 20:18:11, sergey.vfx wrote:
> On 2013/09/23 15:14:20, brechtvl wrote:
> >
>
https://codereview.appspot.com/13778045/diff/1/release/scripts/startup/bl_ui/...
> > File release/scripts/startup/bl_ui/properties_render.py (right):
> > 
> >
>
https://codereview.appspot.com/13778045/diff/1/release/scripts/startup/bl_ui/...
> > release/scripts/startup/bl_ui/properties_render.py:551: if rd.bake_type ==
> > 'DISPLACEMENT':
> > Shouldn't this be its own bake type? Not sure why it would be under
> > displacement.
> 
> Well, historical question. Internally derivatives are being calculated from
> displacement map. We could do the following: add "Derivative Map" baker type,
> which will internally use displacement baker + derivative filtering and
deliver
> derivative map to the user.
> 
> Does it sound like a good plan?

Yes.

> >
>
https://codereview.appspot.com/13778045/diff/1/release/scripts/startup/bl_ui/...
> > release/scripts/startup/bl_ui/properties_render.py:556: col.prop(rd,
> > "use_bake_user_scale")
> > This could be on the same row as the bake user scale, just a checkbox
without
> > text.
> 
> Yep, thought this as well. Not big fan of un-labeled checkboxes, but if you
> think it'll be more clear this way ot so much fussed to change.

I think it's clear enough to just have the checkbox, if the label in the textbox
says User Scale.

> Also, do you think properties descriptions are clear enough?

Thinking about this further, I don't even understand what this user scale is
supposed to do. "Multiplier adapts the signed derivatives to the height map"?

When is the user supposed to use this, which problem does it solve? When would
you set this lower, higher?

[sergey.vfx, 2013-10-09 09:26:16]

Stage 2

[sergey.vfx, 2013-10-09 09:29:26]

On 2013/09/24 20:40:44, brechtvl wrote:
> On 2013/09/24 20:18:11, sergey.vfx wrote:
> > On 2013/09/23 15:14:20, brechtvl wrote:
> > >
> >
>
https://codereview.appspot.com/13778045/diff/1/release/scripts/startup/bl_ui/...
> > > File release/scripts/startup/bl_ui/properties_render.py (right):
> > > 
> > >
> >
>
https://codereview.appspot.com/13778045/diff/1/release/scripts/startup/bl_ui/...
> > > release/scripts/startup/bl_ui/properties_render.py:551: if rd.bake_type ==
> > > 'DISPLACEMENT':
> > > Shouldn't this be its own bake type? Not sure why it would be under
> > > displacement.
> > 
> > Well, historical question. Internally derivatives are being calculated from
> > displacement map. We could do the following: add "Derivative Map" baker
type,
> > which will internally use displacement baker + derivative filtering and
> deliver
> > derivative map to the user.
> > 
> > Does it sound like a good plan?
> 
> Yes.

Made it dedicated baker type now.

> 
> > >
> >
>
https://codereview.appspot.com/13778045/diff/1/release/scripts/startup/bl_ui/...
> > > release/scripts/startup/bl_ui/properties_render.py:556: col.prop(rd,
> > > "use_bake_user_scale")
> > > This could be on the same row as the bake user scale, just a checkbox
> without
> > > text.
> > 
> > Yep, thought this as well. Not big fan of un-labeled checkboxes, but if you
> > think it'll be more clear this way ot so much fussed to change.
> 
> I think it's clear enough to just have the checkbox, if the label in the
textbox
> says User Scale.
> 
> > Also, do you think properties descriptions are clear enough?
> 
> Thinking about this further, I don't even understand what this user scale is
> supposed to do. "Multiplier adapts the signed derivatives to the height map"?
> 
> When is the user supposed to use this, which problem does it solve? When would
> you set this lower, higher?

This is like a normalization. If you don't use user scale, baked derivative map
would be normalized by it's range. If user scale is enabled, normalization is
not used but derivative map is scaled in a way, so when you apply it on the
object you need to use the same scale as you used during baking.

[brechtvl, 2013-10-09 13:55:52]

> > Thinking about this further, I don't even understand what this user scale is
> > supposed to do. "Multiplier adapts the signed derivatives to the height
map"?
> > 
> > When is the user supposed to use this, which problem does it solve? When
would
> > you set this lower, higher?
> 
> This is like a normalization. If you don't use user scale, baked derivative
map
> would be normalized by it's range. If user scale is enabled, normalization is
> not used but derivative map is scaled in a way, so when you apply it on the
> object you need to use the same scale as you used during baking.

Ok, I would use a description like this then:

"Instead of automatically normalizing to 0..1, apply a user scale to the
derivative map."

[brechtvl, 2013-10-09 13:57:31]

Latest patch LGTM now.