PLANET OPERATIONS
                               
   Wrapping maps of the earth on spheres is probably something everyone has
 had a chance to do by now, mostly because all it takes is to wrap a      
 square brush into a round hole.  This is also what I am doing today, but  
 as a last step to a more involved procedure.  To get started, go into a  
 paint program like Brilliance or DPaint.  We will first make a brush of a
 square grid, so we can see how the warping effects will look on a sphere.
 Turn on the grid option, it's default settings are good enough for this 
 example.  Using the filled rectangle tool, draw a rectangular area with a 
 vertical dimension about 30 pixels larger than the horizontal dimension.  
 Make a grid pattern on this surface, using the grid option and a color
 that shows up on the rectangle.  When the grid is finished, save it in 
 one or two of the spare brush wells, clear the screen and turn off the  
 grid tool.
   This technique will involve viewing the sphere from an orbit in the 
 northern hemisphere using the grid brush we just made.  Grab the grid   
 brush from the spare brush well.  Select "bend-vertical" from the brush 
 distortion control panel, and Bend the center of the brush about 30 pixels
 down.  This gives the grid sort of a "sagging" effect.  Put the brush on 
 the screen, and grab the largest square area from the center of this new 
 grid.
   Now we will wrap this new brush in the usual way.  Select the filled 
 circle tool, then select "stretch" in the draw modes control panel.  Now 
 draw a circle in the center of the screen.  The sagging horizontal lines 
 of the grid have now become lines of lattitude on a convincing sphere, and
 we can see over the top of the north pole.
   The vertical lines of the grid don't converge on the north pole where  
 they should, but this is ok since if we use a planet map, as there are no
 lines to give this away.  There are many places to get a planet map.  
 There is a two color map that comes with DPaint, I have a hi-res 16 color 
 map of the earth on Aminet, included in my Splatterpaint paint program, 
 or you can make a map yourself rather quickly.  My planet map contains the
 extreme polar areas just  to use this technique.
   This technique works best in animations, and you really get the feel of 
 being in a polar orbit of the planet.  I have put my animation of the  
 earth onto Aminet, PlanetaryFlyBy.lha in gfx/anim so you can see how to 
 effectively use this technique in a planetary fly-by animation.
 
 


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                        * Pete Storonskij is the Developer *
                        * of Incinerplex Games and the     *
                        * of the paint program Splatter-   *
                        * Paint.  He can be reached at the *
                        * following address:               * 
                        * Pete W Storonskij                * 
                        * 200 A Street                     * 
                        * Lincoln, NE  68502               *  
                        * USA                              * 
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