Signed-off-by: Ashton Larkin 42042756+adlarkin@users.noreply.github.com

🎉 New feature

Summary

This builds on top of #817 to add light converting functionality from SDF to USD.

There are a few things that may need to be addressed, but they aren't blocking the core functionality (I left some TODO notes in the code to highlight things we might want to address). I think we can start to review this PR now, and then re-visit the TODOs later when time permits to add enhanced functionality. Perhaps we should create an issue that lists what enhanced functionality is missing from the USD -> SDF creator?

I also think we can close #796 because the only test in that PR is for lights, which has been moved to this PR (we will need to address #796 (review), which is also a potential issue with the tests that are written in #817).

Test it

You can run the unit test that has been added in this PR (Light_Sdf2Usd_TEST), or you can try converting https://github.com/ignitionrobotics/ign-gazebo/blob/ign-gazebo6/examples/worlds/lights.sdf to a USD file with the sdf2usd executable that's generated in #817 (this assumes you have PXR installed and have built the usd component of sdformat).

If you want to see how the light intensities look in isaac sim, you'll need to add an object to the lights.sdf file above in order to have the lights reflect off of something. You can add the following code to usd/src/World.cc, which adds a ground plane to the world:

diff --git a/usd/src/World.cc b/usd/src/World.cc
index a3aaa138..90bb81f7 100644
--- a/usd/src/World.cc
+++ b/usd/src/World.cc
@@ -30,6 +30,16 @@
 #include "sdf/World.hh"
 #include "sdf/usd/Light.hh"
 
+// includes needed for creating a plane
+#include <pxr/usd/usdGeom/xform.h>
+#include <ignition/math/Vector3.hh>
+#include <ignition/math/Pose3.hh>
+#include <pxr/usd/usdGeom/cube.h>
+#include <pxr/base/gf/vec3f.h>
+#include <pxr/base/vt/array.h>
+#include <pxr/usd/usdGeom/xformCommonAPI.h>
+#include "sdf/usd/Utils.hh"
+
 namespace usd
 {
   bool ParseSdfWorld(const sdf::World &_world, pxr::UsdStageRefPtr &_stage,
@@ -69,6 +79,23 @@ namespace usd
               << "the moment. Models that are children of the world "
               << "are currently being ignored.\n";
 
+    // temporarily adding ground plane in order to test light intensities
+    const pxr::SdfPath sdfModelPath(_path + "/plane");
+    auto usdModelXform = pxr::UsdGeomXform::Define(_stage, sdfModelPath);
+    ignition::math::Vector3d planePosition(0, 0, -0.25);
+    usd::SetPose(ignition::math::Pose3d(planePosition,
+          ignition::math::Quaterniond::Identity), _stage, sdfModelPath);
+    const pxr::SdfPath geomPath(_path + "/plane/geom");
+    auto usdCube = pxr::UsdGeomCube::Define(_stage, pxr::SdfPath(geomPath));
+    usdCube.CreateSizeAttr().Set(1.0);
+    pxr::GfVec3f endPoint(0.5);
+    pxr::VtArray<pxr::GfVec3f> extentBounds;
+    extentBounds.push_back(-1.0 * endPoint);
+    extentBounds.push_back(endPoint);
+    usdCube.CreateExtentAttr().Set(extentBounds);
+    pxr::UsdGeomXformCommonAPI cubeXformAPI(usdCube);
+    cubeXformAPI.SetScale(pxr::GfVec3f(10, 10, 0.5));
+
     return true;
   }
 }

Checklist

• Signed all commits for DCO
• Added tests
• Added example and/or tutorial
• Updated documentation (as needed)
• Updated migration guide (as needed)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
• While waiting for a review on your PR, please help review another open pull request to support the maintainers

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