dene maxwell wrote:
Hi Paul,
From: Paul Surgeon <[EMAIL PROTECTED]>
On Sunday 15 January 2006 10:25, dene maxwell wrote:
> Hi Paul, to my way of thinking the resolution is not important.
Pythagarus
> is more important, the distance as seen in a birds-eye view as seen
by FGSD
> is not the distance of the terrain. Hence if you cut a material to a
> birds-eye distance of say 10 what ever units it will be stretched
to say
> 14.14 units when the slope is 45 degrees. The greater the slope the
larger
> the slope distortion, in the nth degree a vertical slope will have
zero
> length stretched to infinite length.
>
> Dene
What I mean is that from a "top down" view you need to increase the
resolution
of textures on the slopes so that when you look at the slope from a
perpendicular angle you still get the same resolution as on flat ground.
Example :
If a flat piece of ground has a texture resolution of 1m/pixel then a
slope of
45 degrees should also have a texture resolution of 1m/pixel if you
look at
it from a perpendicular perspective.
agreed
A 45 degree slope viewed from the *top* should have a texture
resolution of
0.707 m/pixel. So from a "top down" view the texture resolution will be
higher. This will "unstretch" those slope textures.
Paul
this certainly seems to follow the geometric logic. One problem...it
doesn't seem to work.
Without being familiar with the code concerned, my impression is that
this logic is not being applied in a way that produces the desired
result or something very important is being over looked in the logic.
Perhaps applying this sinusoidal algorithm is the problem, why not try
giving all perspectives a 1m/pixel view and see if the result is more
pleasing? This might aleast give some idea where the observed
stretching is occurring....yeah?
Here's the downside though ... if you change the texture resolution or
how you project the texture onto the surface based on slope, then you
lose the seamless tiling across triangle edges. We eventually need to
come up with a better way to blend/dither non-tiled edges together, but
for the moment we can't do that.
Regards,
Curt.
--
Curtis Olson http://www.flightgear.org/~curt
HumanFIRST Program http://www.humanfirst.umn.edu/
FlightGear Project http://www.flightgear.org
Unique text: 2f585eeea02e2c79d7b1d8c4963bae2d
-------------------------------------------------------
This SF.net email is sponsored by: Splunk Inc. Do you grep through log files
for problems? Stop! Download the new AJAX search engine that makes
searching your log files as easy as surfing the web. DOWNLOAD SPLUNK!
http://ads.osdn.com/?ad_id=7637&alloc_id=16865&op=click
_______________________________________________
Flightgear-devel mailing list
Flightgear-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/flightgear-devel
