| Re: Depth visibility with Object Graphics !!! [message #39537 is a reply to message #39462] |
Tue, 25 May 2004 10:54   |
Rick Towler
Messages: 821
Registered: August 1998
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Senior Member |
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"Antonio Santiago" wrote...
> Well, thanks for your help, but that's not really i mean (perhaps it is
> due to my bad english, sorry).
You haven't convinced me that what Ben is talking about isn't what you mean.
You can do it without texture mapping your image but everything is going to
be in image coordinates. Make sure your line coordinates are appropriate.
> I have a model inside which i put an IDLgrImage as a map of a portion of
> Spain. Also i put an IDLgrPolyline to make seleccions (as a line) over
> the map.
Where are you setting the DEPTH_TEST_DISABLE or DEPTH_TEST_FUNCTION
keywords? If both of these atoms are in a single model setting these
keywords for the model will have no effect. You will need to set the
DEPTH_TEST_FUNCTION keyword of your polyline to "always pass" (I think it is
8 but don't have IDL in front of me).
> My problem is that the line is never seen because i put the map
> int the model after put the line, it is the map overlaps the line.
Assuming you aren't using alpha blending the order in which you add your
atoms to the model shouldn't matter as long as they have different Z values.
Remember, images that aren't texture mapped are rendered at Z=0. Your line
must have +Z values.
If you hide the image, can you see the line?
-Rick
>
> Ben Tupper wrote:
>> Antonio Santiago wrote:
>>
>>> Hi,
>>>
>>> i am working with Object Grpahics and i hace a problem :)
>>>
>>> I have put on a model two objects. Firts, i must put an IDLgrPolyline
>>> betwen two points (a line) that i can modify to select one trajectory.
>>> Second i put an IDLgrImage.
>>> My problem is that image is drawing over the polyline. I play with
>>> DEPTH_TEST_DISABLE and DEPT_TEST_FUNCTION, but always the image is
>>> drawing over the polyline.
>>>
>>
>>>
>>
>> Hi,
>>
>> IDL renders images at Z=0 always. To get around this you have to map
>> the image as a texture map onto a polygon; then set the Z values for the
>> polygon to something 'further' away than your trajectory. There is an
>> example here...
>>
>> http://tinyurl.com/3h5aw
>>
>> Ben
>
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