====== SphericalDistort ======


===== Plugin information ===

^  Authors | [[user>Aaron]] and [[user>Tillot]] |
^  Description | Applies a spherical distortion to a heightfield and water map. |
^  Menu option | '//Extensions->SphericalDistort//' |
^  Download link | [[http://www.bundysoft.com/L3DT/downloads/plugins/bin/SphericalDistort-bin.zip|SphericalDistort-bin.zip]] |
^  Source code | [[bundydocs>zeolite:downloads:examples|Over here]] |


===== What does it do? =====

A picture tells a thousand words, so here's three thousand:

^  Before  ^  After (pos. radius)  ^  After (neg. radius)  ^
| {{:plugins:calc:atsphericaldistort:sphdist_before.jpg?280|Before distortion}} | {{:plugins:calc:atsphericaldistort:sphdist_after.jpg?280|Positive radius}}  | {{:plugins:calc:atsphericaldistort:sphdist_after2.jpg?280|Negative radius}}  |

As you can see, //SphericalDistort// distorts the heightfield as if it were on a sphere. 

<note important>
This plugin, and L3DT in general, cannot produce //complete// spherical worlds. This is due to some [[wp>Topology|topological]] differences between planes and spheres. 
</note>

===== Using SphericalDistort =====

When you select the '//Extensions->SphericalDistort->Apply spherical distortion//' option, you will be asked to enter the sphere radius, which is measured in kilometres. Regarding the radius:
  * The default value is the radius of Earth (6400km). 
  * A negative value will create an inner-sphere effect, or can be used to un-do a positive distortion.
  * You should not use radii smaller in magnitude than about 4x the largest side-length of your map, as heightfields tend to look a bit silly when tilted too far (see screenshots above). 



===== Extended clipping options (by Tillot) =====

I hacked the source for the SphericalDistort plugin to allow for limiting the curvature in the x,y, or at some specified radius.  This allows for 'pieces' of a sphere to be generated kind of like a cookie cutter.  The option is available using the 'Extensions->SphericalDistort->Apply spherical distortion (extended options)' menu option.

Here's the heightmap:

{{ :projects:terrainsliceheightmap.jpg?300 |:projects:terrainsliceheightmap.jpg}}

Here's a terrain screenshot:

{{ :projects:terrainslice.jpg?600 |:projects:terrainslice.jpg}}

This plugin doesn't currently allow removing the surrounding terrain edges, but will some day (see to-do list). 

If the terrain is converted into a poly mesh it would then be as simple as using poly editing tool like Maya, Max, Lightwave, or Blender to cut out the pieces and stitch them together into a sphere.

===== To-do list =====

  * Run in L3DT's worker thread.
  * Make last used settings persistent.
  * Export clipped area.
  * Set MAPFLAG_INVALID for TN, LM and TX (if UseLM enabled).
 
===== Changes =====


**2009/03/26**
  * Changed function arguments to VarID_hvars from VarID_maps.
  * Updated to Zeolite v2.7.1.


**2008/12/03**
  * Added support for 'undo'.

**2006/11/21**
  * Fixed fault with variable renaming in extended version.

**2006/11/16**
  * Changed to include Tillot's modifications.

**2006/10/23**
  * Changed radius from metres to kilometres.
  * Distort the water map too.
  * Updated MAPFLAG_MODIFIED for HF & WM, so maps are saved after distortion.
  * Released with L3DT v2.4b build 5.

**2006/10/22**
  * Released.