parse transmission, add test

Signed-off-by: Ian Chen <[email protected]>
gazebosim · Mar 1, 2024 · 98a9aaf · 98a9aaf
1 parent 3374a3b
commit 98a9aaf
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Showing 3 changed files with 41 additions and 2 deletions.
diff --git a/graphics/src/AssimpLoader.cc b/graphics/src/AssimpLoader.cc
@@ -357,8 +357,24 @@ MaterialPtr AssimpLoader::Implementation::CreateMaterial(
   }
   float opacity = 1.0;
   ret = assimpMat->Get(AI_MATKEY_OPACITY, opacity);
-  mat->SetTransparency(1.0 - opacity);
-  mat->SetBlendFactors(opacity, 1.0 - opacity);
+  if (ret == AI_SUCCESS)
+  {
+    mat->SetTransparency(1.0 - opacity);
+    mat->SetBlendFactors(opacity, 1.0 - opacity);
+  }
+
+  // basic support for transmission - currently just overrides opacity
+  // \todo(iche033) The transmission factor can be used with volume
+  // material extension to simulate effects like refraction
+  // so consider also extending support for other properties like
+  // AI_MATKEY_VOLUME_THICKNESS_FACTOR
+  float transmission = 0.0;
+  ret = assimpMat->Get(AI_MATKEY_TRANSMISSION_FACTOR, transmission);
+  if (ret == AI_SUCCESS)
+  {
+    mat->SetTransparency(transmission);
+  }
+
   // TODO(luca) more than one texture, Gazebo assumes UV index 0
   Pbr pbr;
   aiString texturePath(_path.c_str());
@@ -593,6 +609,7 @@ std::string AssimpLoader::Implementation::GenerateTextureName(
     "_" + _type;
 }
 
+//////////////////////////////////////////////////
 SubMesh AssimpLoader::Implementation::CreateSubMesh(
     const aiMesh* _assimpMesh, const math::Matrix4d& _transform) const
 {

diff --git a/graphics/src/AssimpLoader_TEST.cc b/graphics/src/AssimpLoader_TEST.cc
@@ -665,6 +665,28 @@ TEST_F(AssimpLoader, LoadGlTF2BoxExternalTexture)
   delete mesh;
 }
 
+/////////////////////////////////////////////////
+// Open a gltf mesh with transmission extension
+TEST_F(AssimpLoader, LoadGlTF2BoxTransmission)
+{
+  common::AssimpLoader loader;
+  common::Mesh *mesh = loader.Load(
+      common::testing::TestFile("data", "box_transmission.glb"));
+
+  EXPECT_STREQ("unknown", mesh->Name().c_str());
+
+  // Make sure we can read the submesh name
+  EXPECT_STREQ("Cube", mesh->SubMeshByIndex(0).lock()->Name().c_str());
+
+  EXPECT_EQ(mesh->MaterialCount(), 1u);
+
+  const common::MaterialPtr mat = mesh->MaterialByIndex(0u);
+  ASSERT_TRUE(mat.get());
+  // transmission currently modeled as transparency
+  EXPECT_FLOAT_EQ(0.1, mat->Transparency());
+  delete mesh;
+}
+
 /////////////////////////////////////////////////
 // This test loads a box glb mesh with embedded compressed jpeg texture
 TEST_F(AssimpLoader, LoadGlTF2BoxWithJPEGTexture)

diff --git a/test/data/box_transmission.glb b/test/data/box_transmission.glb