On 08/17/2008 10:01 AM, Ron Jensen wrote: >> This particular patch was greatly discussed
Yes, it was greatly discussed. >> and the decision was made >> not to include it in the main code base. There was no consensus on that point. >> The <bias> tag was added as >> the fix for this "problem". There was no consensus that the <bias> tag made much sense. Here is a good summary of the discussion: On 03/09/2007 01:18 PM, Jim Wilson wrote: > Hi Everybody, > > > Just to clarify, I wrote the textranslate and texrotate animations > (they are animations) while doing the displays for the 747. They are > for sliding and rotating texture mappings on an 3D object, and have > nothing per se to do with digits. The first problem I was trying to > solve was sliding the ASI and Altitude tapes on the PFD. Then it was > the rose animation. > > The problem of producing the alpha and digital displays (it was never > about "numbers") had been dogging me, and in the end I never got > around to really solving the issue. It just so happend that I was > able to use the texture translation for placing numeric values by > creating a texture that had a bunch of digits and sliding it around. > By adding the step parameter I was able to make it either scroll > smoothly like the altitude value or just snap the digit in place as > on most digital displays. IIRC the IAS display also has a sort of > odometer "drum" behavior even though it is a flat electronic display. > Note that the animations were also used for displaying some > alphanumeric NAV data. > > Essentially, I'm saying that Andy was right. Also, there really was > no intention to handle fractional numeric values or digits for that > matter. It just happened that other modelers picked up on the > technique, as there was no other method available, and it went quite > a bit farther than was ever intended. > > In that context, the addition of the bias tag doesn't really make a > whole lot of sense, but if it helps someone out, that's fine. These > functions are a useful way to do all kinds of things with sliding and > rotating textures, but they are a very cumbersome way of doing > alphanumeric data displays. I agree with Jim Wilson and Andy Ross that the <bias> tag doesn't make a whole lot of sense. If you want to use it, go ahead, but don't pretend it "fixes" the problem ... and don't use it as a pretext for derailing efforts to really fix the problem. The only thing that really makes sense is to implement a set of formatting directives that is actually suitable for digits. *) This will make the code for digit displays much much more compact. Writing the code will be less laborious and less error-prone. *) Then textranslate can be restricted to its intended purpose, namely tapes and drums. *) Beware that real instruments /round/ some things and then /truncate/ other things, so a one-size-fits-all approach will not work, as I pointed out a year and a half ago. The formatting directives will need to include some things that are documented to do rounding (such as sprintf) and some things that are documented to do truncation (such as substr). ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
