feat: Modify testrender to work with triangle meshes (#1865)

testrender was originally envisioned as a tiny example renderer that should only handle spheres/planes. Over time several groups have expressed the wish for it to handle arbitrary geometry instead. This PR replaces the sphere and quad primitives with triangle meshes.

I am making use of the (embedded) rapidobj library to load models in the .obj format. The original .xml scene format remains, so that you can combine several models together as well as declare and assign the osl shader networks you want to these meshes. For backwards compatibility, spheres and planes are still supported via tessellation (you specify how many subdivisions you want). In the case of .obj scenes, the shader assignment can be done either by the mesh name or the material name.

I am submitting this to get the review kickstarted. The history of commits includes some fairly large test scenes that should be squashed away to go into the main repo. Files over 50Mb are recommended to use git lfs, but we probably want to figure that out as a different task (possibly handle it via a separate repo).

The handling of derivatives is not totally correct yet, but the behavior is compatible with the previous (incorrect) handling of derivatives we had before.


---------

Signed-off-by: Chris Kulla <[email protected]>

.gitignore

@@ -10,4 +10,4 @@ build
 *.log
 .vscode
 .envrc
-
+.DS_Store

src/cmake/testing.cmake

@@ -127,6 +127,7 @@ macro ( TESTSUITE )
         # Run the test unoptimized, unless it matches a few patterns that
         # we don't test unoptimized (or has an OPTIMIZEONLY marker file).
         if (NOT _testname MATCHES "optix"
+            AND NOT _testname MATCHES "render"
             AND NOT EXISTS "${_testsrcdir}/NOSCALAR"
             AND NOT EXISTS "${_testsrcdir}/BATCHED_REGRESSION"
             AND NOT EXISTS "${_testsrcdir}/OPTIMIZEONLY")
@@ -137,6 +138,7 @@ macro ( TESTSUITE )
         # services keeping unoptimized, unless it matches a few patterns that
         # we don't test unoptimized (or has an OPTIMIZEONLY marker file).
         if (NOT _testname MATCHES "optix"
+            AND NOT _testname MATCHES "render"
             AND NOT EXISTS "${_testsrcdir}/NOSCALAR"
             AND NOT EXISTS "${_testsrcdir}/BATCHED_REGRESSION"
             AND NOT EXISTS "${_testsrcdir}/OPTIMIZEONLY"
@@ -159,6 +161,7 @@ macro ( TESTSUITE )
         # optimization, triggered by setting TESTSHADE_OPT env variable.
         # Skip OptiX-only tests and those with a NOOPTIMIZE marker file.
         if (NOT _testname MATCHES "optix"
+            AND NOT _testname MATCHES "render"
             AND NOT EXISTS "${_testsrcdir}/NOSCALAR"
             AND NOT EXISTS "${_testsrcdir}/BATCHED_REGRESSION"
             AND NOT EXISTS "${_testsrcdir}/NOOPTIMIZE"
@@ -350,6 +353,7 @@ macro (osl_add_all_tests)
                 raytype raytype-reg raytype-specialized regex-reg
                 reparam reparam-arrays reparam-string testoptix-reparam
                 render-background render-bumptest
+                render-bunny
                 render-cornell render-furnace-diffuse
                 render-mx-furnace-burley-diffuse
                 render-mx-furnace-oren-nayar

src/testrender/CMakeLists.txt

@@ -6,8 +6,12 @@
 set (testrender_srcs
      shading.cpp
      simpleraytracer.cpp
+     scene.cpp
+     bvh.cpp
      testrender.cpp)
 
+find_package(Threads REQUIRED)
+
 if (OSL_USE_OPTIX)
     list (APPEND testrender_srcs optixraytracer.cpp)
     set (testrender_cuda_srcs
@@ -69,7 +73,8 @@ add_executable (testrender ${testrender_srcs})
 target_link_libraries (testrender
     PRIVATE
         oslexec oslquery
-        pugixml::pugixml)
+        pugixml::pugixml
+        Threads::Threads)
 
 osl_optix_target (testrender)