XRT is a raytracing based programmable rendering system for photo-realistic image synthesis built around a plug-in architecture design.


XRT 1.3.1 released

Posted: 10 Mar 2012 19:04
Tags: downloads


The major change in this release is the upgrade to OIIO 1.0. Be aware that the version bundled with XRT differs slightly from the genuine 1.0 version. It fixes a problem with the maketx utility (to be commited soon to the GitHub master) and compatibility with XP has been restored (yes, I still have an XP box!).

Environment mapping is now working as demonstrated on the right. Previously, a call to environment() in a shader would always fire rays. Now, depending on the argument, it will also sample a texture. The RIB file for this picture is included in the XRT examples archive. I have also updated a few examples to account for the change of behaviour and restore raytracing where needed.

I have made some changes to XRT C++ API. In the original Gelato specification, Input only accepts parameters through a single string which has to be parsed. This is not very flexible and akin to reinventing the wheel. Actually, using "user attributes" to pass parameters is much easier: the Generator calls GetAttribute to get values set before the Input call with Attribute. The only issue is that attributes are persistent and can possibly interfere with other Generators. You are safe if you use PushAttributes/PopAttributes to keep the "user attributes" stack clean. There has to be a better way.

Things get much simpler if Input behaves like Camera, Output, Shader, Light, or any geometric primitive: all calls to Parameter are saved into a “pending parameter” list. This list is passed to the Generator constructor and is cleared by XRT afterwards. This allows for a greater flexibility and a greater consistency.

Finally, a very annoying bug has been fixed: sometimes, rendering was freezing on startup.

As usual, this version and the updated documentation are available in the Downloads page.

For a complete list of changes, see the change log.

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