Ok I think this an depth test problem. The alpha is showing through the
terrain if it is folded as if the depth check is disabled.
It should be :
glEnable( GL_DEPTH_TEST );
glDepthFunc( GL_LEQUAL );
Is this how decals are implemented?
Dave
----- Original Message -----
From: "Kelvin Chung" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Cc: <[EMAIL PROTECTED]>
Sent: Tuesday, September 10, 2002 8:52 PM
Subject: Re: Decal + Alpha blending problem
Hi David,
Can you please send us a test case to verify ?
As far as I known transparency object under descending of OrderedGroup
will not render in the last transparency pass. This is not change
since v1.2.1 (see attachment).
Thanks.
- Kelvin
----------------
Java 3D Team
Sun Microsystems Inc.
>> ------------- Begin Forwarded Message -------------
>>
>> Subject: Re: Decal + Alpha blending problem
>> To: Doug Twilleager <[EMAIL PROTECTED]>
>> MIME-version: 1.0
>> X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2600.0000
>> Content-transfer-encoding: 7bit
>> X-Priority: 3
>> X-MSMail-priority: Normal
>>
>> Thanks Doug! Is this bug slated to be fixed against 1.3?
>>
>> Dave
>>
>> ----- Original Message -----
>> From: "Doug Twilleager" <[EMAIL PROTECTED]>
>> To: <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>
>> Sent: Monday, September 09, 2002 7:24 PM
>> Subject: Re: Decal + Alpha blending problem
>>
>>
>> Since DecalGroup is a subclass of OrderedGroup, this is a bug.
>> The renderer should execute in the following order:
>>
>> - Opaque objects
>> - Ordered objects
>> - Transparent objects
>>
>> If you can fit the passes into existing texture blend modes, then
>> your second solution should work. Just remember that we have a
>> current limitation that extended combine modes don't work when we
>> fallback
>> to
>> multipass emulation of multitexture. That would happen when you are
>> trying to use more texture units than the hardware supports.
>>
>> Doug Twilleager
>> Java 3D Team
>> Sun Microsystems
>>
>>
>>> Subject: Decal + Alpha blending problem
>>> To: [EMAIL PROTECTED]
>>> Cc: Doug Twilleager <[EMAIL PROTECTED]>, Kelvin Chung
>>>
>> <[EMAIL PROTECTED]>
>>
>>> MIME-version: 1.0
>>> X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2600.0000
>>> Content-transfer-encoding: 7bit
>>> X-Priority: 3
>>> X-MSMail-priority: Normal
>>>
>>> Question:
>>>
>>> Decal groups seme to have an artifact that I can't seem to get
>>> around. If
>>>
>> I
>>
>>> am alpha blending between terrain layers java3d is still rendering
>>> the the
>>> alpha blended layers in the transparency pass at the end of the
>>> rendering
>>> cycle, even if these layers are in a decal group. First of all, is
>>> there
>>> any way to force these to be blended in multiple passes in the solid
>>> rendering portion? The problem is that since it is done after all
>>> solids
>>>
>> it
>>
>>> contends with other alpha blended shapes in some instances. Since it is
>>> coplanar with the terrain there is no reason it should do this.
>>>
>>> So
>>>
>>> decal group (coplanar, same geometry array)
>>> - solid shape
>>> - alpha blend
>>> - alpha blend
>>>
>>> If I am missing some option please let me know.
>>>
>>> Secondly, would it be possible to pile them all into texture units
>>> within
>>> the same shape and then use combine (somehow) to achieve the same
>>> effect?
>>>
>>> Thanks!
>>>
>>> David Yazel
>>>
>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>>
>>
>>
>>
>>
>> ------------- End Forwarded Message -------------
>>
>>
>>
>
>
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