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Re: Simple renderer in .net with direct3d
avatarNovember 25, 2013 11:45PM
I can't directly answer your question, since I don't know Direct3D. However, I can give an overview of what LDView does.

IIRC, LDView first calculates the bounding box for the whole model. Next, using the center of that box, it calculates the bounding sphere for the whole model. It then moves the camera to the center of the sphere, then backs it up by an amount calculated based on the FOV and the sphere radius. I believe that the distance to move back is:

radius / sin(fov/2)

Note that I believe fov in the above is either the horizontal FOV (if the window is taller than it is wide) or the vertical FOV (if the window is wider than it is tall). OpenGL expects you to always give it the vertical FOV, so LDView calculates that based on the horizontal FOV when the window is taller than it is wide. I suspect that Direct3D also wants the vertical FOV. If you always use the same FOV value, no matter what the window shape, I believe you'll get a cropped image if you use that in the above calculation when the window is taller than it is wide.

If have have the horizontal FOV, the vertical FOV can be calculated like so:

VFOV = 2*atan(tan(hfov/2)/(width/height))

Note also that LDView's default zoom level (calculated as per above) is set up so that no matter how you rotate the model, it will always be fully visible (which is why it uses the bounding sphere).

LDView's "zoom to fit" functionality uses an algorithm I got from Lars C. Hassing that solves numerous equations for numerous unknowns to move the view pyramid around until at least two points on the model are exactly at the edge of the view. (Those two points are either at the top and bottom of the view, or at the left and right.) The pyramid is moved in such a way that the view direction remains constant, but the camera position moves in all three dimensions, so the look-at point also moves.
SubjectAuthorViewsPosted
Simple renderer in .net with SharpGL (openGL) Michael Heidemann522November 23, 2013 04:48AM
Re: Simple renderer in .net with direct3d Roland Melkert221November 23, 2013 09:47AM
Re: Simple renderer in .net with direct3d Michael Heidemann188November 23, 2013 10:16AM
Re: Simple renderer in .net with direct3d Roland Melkert180November 23, 2013 10:36AM
Re: Simple renderer in .net with direct3d Michael Heidemann160November 23, 2013 10:39AM
Re: Simple renderer in .net with direct3d Michael Heidemann392November 23, 2013 10:48AM
Re: Simple renderer in .net with direct3d Roland Melkert129November 23, 2013 11:15AM
Re: Simple renderer in .net with direct3d Michael Heidemann152November 23, 2013 11:19AM
Re: Simple renderer in .net with direct3d Roland Melkert135November 23, 2013 11:22AM
Re: Simple renderer in .net with direct3d Michael Heidemann153November 23, 2013 11:32AM
Re: Simple renderer in .net with direct3d Roland Melkert138November 23, 2013 11:40AM
Re: Simple renderer in .net with direct3d Michael Heidemann146November 23, 2013 11:54AM
Re: Simple renderer in .net with direct3d Michael Heidemann159November 23, 2013 11:59AM
Re: Simple renderer in .net with direct3d Roland Melkert149November 23, 2013 12:27PM
Re: Simple renderer in .net with direct3d Michael Heidemann127November 23, 2013 12:16PM
Re: Simple renderer in .net with direct3d Roland Melkert148November 23, 2013 12:25PM
Re: Simple renderer in .net with direct3d Michael Heidemann172November 23, 2013 12:30PM
Re: Simple renderer in .net with direct3d Roland Melkert153November 23, 2013 12:50PM
Re: Simple renderer in .net with direct3d Michael Heidemann138November 23, 2013 12:58PM
Re: Simple renderer in .net with direct3d Roland Melkert122November 23, 2013 01:06PM
Re: Simple renderer in .net with direct3d Michael Heidemann157November 23, 2013 01:13PM
Re: Simple renderer in .net with direct3d Travis Cobbs279November 25, 2013 11:45PM
Re: Simple renderer in .net with direct3d Michael Heidemann214November 26, 2013 09:36AM
Re: Simple renderer in .net with direct3d Michael Heidemann182November 29, 2013 03:18AM
Re: Simple renderer in .net with direct3d Roland Melkert191November 29, 2013 10:22AM
Re: Simple renderer in .net with direct3d Michael Heidemann155November 30, 2013 02:55AM
Re: Simple renderer in .net with direct3d Michael Heidemann133November 30, 2013 07:08AM
Re: Simple renderer in .net with openTK (openGL) Michael Heidemann207November 30, 2013 07:48AM
Re: Simple renderer in .net with openTK (openGL) Roland Melkert181November 30, 2013 10:40AM
Re: Simple renderer in .net with openTK (openGL) Michael Heidemann137November 30, 2013 11:44AM
Re: Simple renderer in .net with openTK (openGL) Roland Melkert321November 30, 2013 12:04PM
Re: Simple renderer in .net with SharpGL (openGL) Michael Heidemann249December 01, 2013 04:33AM
Re: Simple renderer in .net with SharpGL (openGL) Michael Heidemann214December 01, 2013 08:34AM
Re: Simple renderer in .net with SharpGL (openGL) Michael Heidemann197December 01, 2013 08:58AM
Re: Simple renderer in .net with SharpGL (openGL) Roland Melkert201December 01, 2013 09:51AM
Re: Simple renderer in .net with SharpGL (openGL) Michael Heidemann335December 01, 2013 09:54AM
Re: Simple renderer in .net with SharpGL (openGL) Travis Cobbs217December 01, 2013 09:08PM
Re: Simple renderer in .net with SharpGL (openGL) Michael Heidemann195December 02, 2013 09:58AM
Re: Simple renderer in .net with SharpGL (openGL) Roland Melkert216December 02, 2013 10:05AM
Re: Simple renderer in .net with SharpGL (openGL) Steffen212December 02, 2013 11:58PM
Re: Simple renderer in .net with SharpGL (openGL) Michael Heidemann225December 03, 2013 08:53AM
Re: Simple renderer in .net with SharpGL (openGL) Steffen322December 07, 2013 01:57AM
Re: Simple renderer in .net with SharpGL (openGL) Michael Heidemann177December 07, 2013 03:10AM
Re: Simple renderer in .net with SharpGL (openGL) Roland Melkert257December 02, 2013 09:59AM
Re: Simple renderer in .net with SharpGL (openGL) Michael Heidemann238December 06, 2013 09:30AM
Re: Simple renderer in .net with SharpGL (openGL) Roland Melkert169December 06, 2013 10:20AM
Re: Simple renderer in .net with SharpGL (openGL) Michael Heidemann154December 06, 2013 11:30AM
Re: Simple renderer in .net with SharpGL (openGL) Roland Melkert180December 06, 2013 12:27PM
Re: Simple renderer in .net with SharpGL (openGL) Michael Heidemann171December 06, 2013 01:22PM
Re: Simple renderer in .net with SharpGL (openGL) Travis Cobbs198December 06, 2013 03:25PM
Re: Simple renderer in .net with SharpGL (openGL) Michael Heidemann304December 06, 2013 11:06PM
Re: Simple renderer in .net with SharpGL (openGL) Roland Melkert186December 07, 2013 10:11AM
Re: Simple renderer in .net with SharpGL (openGL) Michael Heidemann295December 08, 2013 02:46AM



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