test: Add StandardShaderBall test scene and common models directory

src/cmake/testing.cmake

@@ -431,6 +431,7 @@ macro (osl_add_all_tests)
                 render-mx-medium-vdf
                 render-mx-medium-vdf-glass
                 render-microfacet render-oren-nayar
+                render-shaderball
                 render-spi-thinlayer
                 render-uv render-veachmis render-ward
                 render-raytypes

testsuite/common/models/shaderball/README.md

@@ -0,0 +1,73 @@
+<!-- Copyright Contributors to the Open Shading Language project. -->
+<!-- SPDX-License-Identifier: CC-BY-4.0 -->
+
+Standard Shader Ball
+====================
+
+The geometry in this directory is derived from the **StandardShaderBall**
+asset published by the USD Working Group:
+
+  https://github.com/usd-wg/assets/tree/main/full_assets/StandardShaderBall
+
+The matching textures live in `testsuite/render-shaderball/maps` and come
+from the same asset.
+
+
+Credits
+-------
+
+* Chris Rydalch — geometry and textures
+* André Mazzone — specification and validation
+* Thomas Anagnostou — original scene, inspiration, and consultation
+
+Per the upstream README, the asset descends from the "Simball" / "Material
+Preview" scene created by Thomas Anagnostou, which was originally released
+under a Creative Commons Attribution-ShareAlike license. The USD Working
+Group asset is released under Creative Commons Attribution 4.0.
+
+
+License
+-------
+
+This material is licensed under the Creative Commons Attribution 4.0
+International License (`SPDX-License-Identifier: CC-BY-4.0`).
+
+To view a copy of this license, visit
+https://creativecommons.org/licenses/by/4.0/ or send a letter to
+Creative Commons, PO Box 1866, Mountain View, CA 94042, USA.
+
+The upstream license file is at:
+https://github.com/usd-wg/assets/blob/main/full_assets/StandardShaderBall/LICENCE
+
+Note that this is a different license from the BSD-3-Clause license that
+covers OSL's own source code. See the repository's `THIRD-PARTY.md`.
+
+
+Modifications
+-------------
+
+`shaderball.obj` and `shaderball.mtl` are **modified** from the upstream
+asset. The upstream asset is distributed as USD with MaterialX shading
+networks; OSL's `testrender` reads Wavefront OBJ, so the scene was imported
+into Blender 3.4.1 and re-exported as OBJ + MTL. The changes are:
+
+* **Format conversion**, USD to Wavefront OBJ. The USD stage is flattened
+  into a single file, with each mesh written as an OBJ group.
+
+* **Triangulation.** All faces in the exported mesh are triangles.
+  UVs and normals are preserved.
+
+* **Shading networks removed.** The upstream MaterialX networks are not
+  carried over. The exported `.mtl` retains the upstream *material names*,
+  which `testrender` uses to bind OSL shader groups.
+
+* **Emissive geometry added.** The upstream asset lights its scene with
+  USD area lights, which are analytic and are not representable
+  in Wavefront OBJ. `testrender` has no area lights either, instead it
+  illuminates a scene with emissive geometry. Light-emitting planes
+  were added in their place, positioned to match the upstream light
+  transforms. These are the `emitterTop0`--`emitterTop3` and
+  `emitterLeft0` groups.
+
+Apart from the added emissive planes, no changes were made to the shape of
+the modeled geometry beyond the triangulation performed by the exporter.

testsuite/common/models/shaderball/shaderball.mtl

@@ -0,0 +1,129 @@
+# StandardShaderBall, Copyright (c) Chris Rydalch, André Mazzone,
+# and Thomas Anagnostou.
+# https://github.com/usd-wg/assets/tree/main/full_assets/StandardShaderBall
+# Licensed under CC BY 4.0: https://creativecommons.org/licenses/by/4.0/
+# SPDX-License-Identifier: CC-BY-4.0
+# Modified from the upstream USD asset: converted to Wavefront OBJ via
+# Blender. See README.md in this directory for details.
+# Blender 3.4.1 MTL File: 'shaderball-light-geo.blend'
+# www.blender.org
+
+newmtl back
+Ns 0.000000
+Ka 1.000000 1.000000 1.000000
+Kd 0.800000 0.800000 0.800000
+Ks 0.500000 0.500000 0.500000
+Ke 0.000000 0.000000 0.000000
+Ni 1.000000
+d 1.000000
+illum 2
+
+newmtl backplane
+Ns 360.000000
+Ka 1.000000 1.000000 1.000000
+Kd 0.800000 0.800000 0.800000
+Ks 0.500000 0.500000 0.500000
+Ke 0.000000 0.000000 0.000000
+Ni 1.000000
+d 1.000000
+illum 2
+
+newmtl emitterLeft
+Ns 360.000000
+Ka 1.000000 1.000000 1.000000
+Kd 0.800000 0.800000 0.800000
+Ks 0.500000 0.500000 0.500000
+Ke 0.000000 0.000000 0.000000
+Ni 1.000000
+d 1.000000
+illum 2
+
+newmtl emitterTop
+Ns 360.000000
+Ka 1.000000 1.000000 1.000000
+Kd 0.800000 0.800000 0.800000
+Ks 0.500000 0.500000 0.500000
+Ke 0.000000 0.000000 0.000000
+Ni 1.000000
+d 1.000000
+illum 2
+
+newmtl front
+Ns 0.000000
+Ka 1.000000 1.000000 1.000000
+Kd 0.800000 0.800000 0.800000
+Ks 0.500000 0.500000 0.500000
+Ke 0.000000 0.000000 0.000000
+Ni 1.000000
+d 1.000000
+illum 2
+
+newmtl ground
+Ns 0.000000
+Ka 1.000000 1.000000 1.000000
+Kd 0.800000 0.800000 0.800000
+Ks 0.500000 0.500000 0.500000
+Ke 0.000000 0.000000 0.000000
+Ni 1.000000
+d 1.000000
+illum 2
+
+newmtl left
+Ns 0.000000
+Ka 1.000000 1.000000 1.000000
+Kd 0.800000 0.800000 0.800000
+Ks 0.500000 0.500000 0.500000
+Ke 0.000000 0.000000 0.000000
+Ni 1.000000
+d 1.000000
+illum 2
+
+newmtl material_surface
+Ns 360.000000
+Ka 1.000000 1.000000 1.000000
+Kd 0.800000 0.800000 0.800000
+Ks 0.500000 0.500000 0.500000
+Ke 0.000000 0.000000 0.000000
+Ni 1.000000
+d 1.000000
+illum 2
+
+newmtl neutral
+Ns 0.000000
+Ka 1.000000 1.000000 1.000000
+Kd 0.800000 0.800000 0.800000
+Ks 0.500000 0.500000 0.500000
+Ke 0.000000 0.000000 0.000000
+Ni 1.000000
+d 1.000000
+illum 2
+
+newmtl right
+Ns 0.000000
+Ka 1.000000 1.000000 1.000000
+Kd 0.800000 0.800000 0.800000
+Ks 0.500000 0.500000 0.500000
+Ke 0.000000 0.000000 0.000000
+Ni 1.000000
+d 1.000000
+illum 2
+
+newmtl sss_bars
+Ns 0.000000
+Ka 1.000000 1.000000 1.000000
+Kd 1.000000 1.000000 1.000000
+Ks 0.500000 0.500000 0.500000
+Ke 0.000000 0.000000 0.000000
+Ni 1.000000
+d 1.000000
+illum 2
+
+newmtl top
+Ns 0.000000
+Ka 1.000000 1.000000 1.000000
+Kd 0.800000 0.800000 0.800000
+Ks 0.500000 0.500000 0.500000
+Ke 0.000000 0.000000 0.000000
+Ni 1.000000
+d 1.000000
+illum 2