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https://github.com/PixarAnimationStudios/OpenSubdiv
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0d4582b34c
Make the sample locations dynamic by adding a velocity vector. Face boundary crossing is handled using the new ptex adjacency functionality recently added to the Far::TopologyRefiner.
83 lines
2.8 KiB
ReStructuredText
83 lines
2.8 KiB
ReStructuredText
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Copyright 2013 Pixar
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Licensed under the Apache License, Version 2.0 (the "Apache License")
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with the following modification; you may not use this file except in
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compliance with the Apache License and the following modification to it:
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Section 6. Trademarks. is deleted and replaced with:
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6. Trademarks. This License does not grant permission to use the trade
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names, trademarks, service marks, or product names of the Licensor
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and its affiliates, except as required to comply with Section 4(c) of
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the License and to reproduce the content of the NOTICE file.
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You may obtain a copy of the Apache License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the Apache License with the above modification is
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distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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KIND, either express or implied. See the Apache License for the specific
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language governing permissions and limitations under the Apache License.
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glEvalLimit
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-----------
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.. contents::
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:local:
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:backlinks: none
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SYNOPSIS
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========
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.. parsed-literal::
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:class: codefhead
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**limitEval** [**-f**] *objfile(s)*
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DESCRIPTION
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===========
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``glEvalLimit`` is a stand-alone application that showcases the limit surface
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Eval module. On the given shape, random samples are generated in local s,t space.
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Vertex, varying and face-varying data is then computed on the surface limit and
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displayed as colors.
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In order to emphasize the dynamic nature of the EvalLimit API, where the
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locations can be arbitrarily updated before each evaluation, the glEvalLimit
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example treats each sample as a 'ST particle'.
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ST Particles are a simplified parametric-space particle dynamics simulation: each
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particle is assigned a location on the subdivision surface limit that is
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composed of a unique ptex face index, with a local (s,t) parametric pair.
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The system also generates an array of parametric velocties (ds, dt) for each
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particle. An Update() function then applies the velocities to the locations and
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moves the points along the parametric space.
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Face boundaries are managed using a ptex adjacency table obtained from the
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Far::TopologyRefiner. Every time a particle moves outside of the [0.0f, 1.0f]
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parametric range, a 'warp' function moves it to the neighboring face, or
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bounces it, if the edge happens to be a boundary.
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Note: currently the adjacency code does not handle 'diagonal' crossings, nor
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crossings between quand and non-quad faces.
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Multiple controls are available to experiment with the algorithms.
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.. image:: images/glevallimit.jpg
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:width: 400px
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:align: center
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:target: images/glevallimit.jpg
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OPTIONS
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=======
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**-f**
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Launches the application in full-screen mode (if is supported by GLFW on the
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OS)
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.. include:: examples_see_also.rst
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