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Extracting real values from heightmap

Started by edotorpedo Aug 2, 2002 at 7:24 AM 2 replies 250+ views

Original Post

Aug 2, 2002 at 7:24 AM

Hello, I have this problem: My terrain size is about 70000 opengl *units*. My heightmap size is 1024*1024. Now when I create a mesh and try to extract height values from heightmap, very often the location of a vertex is in between two heightmap pixels. Because of this some triangles in my mesh (for example on a terrain hill) are flat, because all vertices relate to the same heightmap pixel. How can I interpolate between pixels. Say I want to extract a pixel from heightmap at location 343.23423, 566.634645 ?? A clue anyone ? Thanks, Edotorpedo

JonnyQuest

Aug 2, 2002 at 7:33 AM

Don''t use a byte-heightmap. To get more detail, just use, say 16 bits per vertex. That gives you 256 times the precision, which should be more than enough. If not, you definitely have good eyes

- hillip@xenoage.de''>JQ
Full Speed Games. Period.

Darjk

Aug 2, 2002 at 7:45 AM

Or you could just add both height values from the 2 neighbouring pixels and divide it by 2 ?
Or if its on a cornor add all 4 neighbouring pixel height values and divide by 4.

JackNathan

Aug 2, 2002 at 11:39 AM

Look into bilinear interpololation to get values between your height map samples.

Jack

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