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DirkB — Hemispheres
Published: 2013-08-17 00:30:58 +0000 UTC; Views: 304; Favourites: 3; Downloads: 96
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Description
Hemispheres
Two hemispheres; top and bottom halves of a sphere.
(Shown: 2 hemispheres attached to a plane.)
This function isn't very spectacular, but it is an important precursor to what's next.
The method used to determine which scanlines are active and which aren't,
needed by the horizontal shift of the Y-axis in the surfaces presented until now,
has an interesting side-effect: the scan could be made to start/stop at any point,
determined by whether the function already/still exists there or not.
This means that we could detach the objects from the carrier surface;
and if we now could also connect top and bottom halves correctly...
All this has been accomplished for the bottom part of the picture:
Two hemispheres connected to make a solid sphere.
(Here: a sphere seen straight on, and one rotated downwards (or as seen from an altitude of +30°).)
I have changed the scan method from intersections with frontal vertical planes, to diagonal vertical planes. So it's no longer necessary to shift the Y-axis to create an illusion of perspective, as in the surfaces so far. In other words: this is an exact parallel projection.
PNG: 1504x1585 pixels, 1-bit palette-less black & white, 55 KB.
