[vtkusers] rescaling glyphs.??

[David Gobbi]

Sorry, I am a little tired and I made a mistake in my last email.

The scale factor is proportional to the depth, not 1/depth.

   David


On Tue, Feb 9, 2010 at 7:22 AM, David Gobbi <david.gobbi at gmail.com> wrote:
> Hi Rakesh,
>
> This will have to be the last email that I answer in this discussion.
>
> Since every glyph is at a different position, you will have to do the
> computation for every glyph.
>
> The result of the dot product is the depth.  Once you have the depth,
> you must compute the scale factor.  Here's a hint: the scale factor
> will be proportional to 1/depth.
>
> Good luck.
>
>   David
>
>
> On Tue, Feb 9, 2010 at 7:13 AM, Rakesh Patil <rakeshthp at in.com> wrote:
>> hello sir,
>>
>> Now suppose, i have to show glyphs at following positions:
>>
>> 78.23564 8.28372 -5
>> 78.32127 8.32736 -10
>> 78.34723 8.42864 50
>> ...
>> 80.23574 9.37256 1800
>>
>> then, for each point i need to calculate the difference and get the dot
>> product with projection direction??
>>
>> is the result of these dot products the scale factor??
>> Coz in that code i didnt find and depth parameter.. only position is there..
>> Am i correct??
>>
>> Thanks
>>
>> ---------- Original message ----------
>> From:David Gobbi< david.gobbi at gmail.com >
>> Date: 09 Feb 10 19:05:11
>> Subject: Re: rescaling glyphs.??
>> To: Rakesh Patil
>>
>> Let camera position be p1, which you can get from camera->GetPosition().
>>
>> Let object position be p2, i.e. the position of a glyph.
>>
>> The vector "v" is the p2 - p1:
>> v[0] = p2[0] - p1[0];
>> v[1] = p2[1] - p1[1];
>> v[2] = p2[2] - p1[2];
>>
>> That's all there is to it.
>>
>>
>>
>> On Tue, Feb 9, 2010 at 6:24 AM, Rakesh Patil wrote:
>>> Hello sir,
>>>
>>> Thanks a lot for you guidance. Please pardon me if am going wrong at any
>>> point.
>>> I'm am still not clear with this point what you said
>>>
>>> "The depth is the dot product of the camera's direction-of-projection with
>>> the vector from the camera's position to the object's position."
>>>
>>> what exactly is a vector from the camera's position to object's position??
>>>
>>> Thanks
>>
>