AssimpImporter: import unrecognized materials + compatibility with 5.1.1

src/MagnumPlugins/AssimpImporter/AssimpImporter.conf

@@ -63,6 +63,17 @@ mergeSkins=false
 # AI_CONFIG_* values, can be changed only before the first file is opened
 ImportColladaIgnoreUpDirection=false
 
+# By default material attributes that aren't recognized as builtin attributes
+# are imported with raw Assimp names and types. Enabling this option completely
+# ignores unrecognized attributes instead.
+ignoreUnrecognizedMaterialData=false
+
+# Don't attempt to recognize builtin material attributes and always import them
+# as raw material data (so e.g. instead of DiffuseColor you'll get
+# $clr.diffuse). Implicitly disables ignoreUnrecognizedMaterialData. Mainly for
+# testing purposes.
+forceRawMaterialData=false
+
 # aiPostProcessSteps, applied to each opened file
 [configuration/postprocess]
 JoinIdenticalVertices=true

src/MagnumPlugins/AssimpImporter/AssimpImporter.h

@@ -265,6 +265,18 @@ verbosity levels in each instance.
 
 -   Only materials with shading mode `aiShadingMode_Phong` are supported
 -   Two-sided property and alpha mode is not imported
+-   Unrecognized Assimp material attributes are imported with their raw names
+    and types. You can find the attribute names in [assimp/material.h](https://github.com/assimp/assimp/blob/master/include/assimp/material.h#L944).
+    Unknown or raw buffer types are imported as
+    @ref MaterialAttributeType::String. To ignore all unrecognized Assimp
+    materials instead, enable the @cb{.ini} ignoreUnrecognizedMaterialData @ce
+    @ref Trade-AssimpImporter-configuration "configuration option".
+-   To load all material attributes with the raw Assimp names and types, enable
+    the @cb{.ini} forceRawMaterialData @ce
+    @ref Trade-AssimpImporter-configuration "configuration option". You will
+    then get attributes like `$clr.diffuse` instead of
+    @ref MaterialAttribute::DiffuseColor. @ref MaterialData::types() will
+    always be empty with this option enabled.
 -   Assimp seems to ignore ambient textures in COLLADA files
 -   For some reason, Assimp 4.1 imports STL models with ambient set to
     @cpp 0xffffff_srgbf @ce, which causes all other color information to be
@@ -278,8 +290,6 @@ verbosity levels in each instance.
 
 -   @ref LightData::intensity() is always @cpp 1.0f @ce, instead Assimp
     premultiplies @ref LightData::color() with the intensity
--   Ambient lights are imported as @ref LightData::Type::Point with attenuation
-    set to @cpp {1.0f, 0.0f, 0.0f} @ce
 -   The following properties are ignored:
     -   Specular color
     -   Custom light orientation vectors --- the orientation is always only
@@ -288,7 +298,9 @@ verbosity levels in each instance.
 
 @subsection Trade-AssimpImporter-behavior-cameras Camera import
 
--   Aspect and up vector properties are not imported
+-   Up vector property is not imported
+-   Orthographic camera support requires Assimp 5.1.0. Earlier versions import
+    them as perspective cameras with arbitrary field of view and aspect ratio.
 
 @subsection Trade-AssimpImporter-behavior-meshes Mesh import
 
@@ -444,9 +456,13 @@ class MAGNUM_ASSIMPIMPORTER_EXPORT AssimpImporter: public AbstractImporter {
 
         MAGNUM_ASSIMPIMPORTER_LOCAL Int doDefaultScene() const override;
         MAGNUM_ASSIMPIMPORTER_LOCAL UnsignedInt doSceneCount() const override;
+        MAGNUM_ASSIMPIMPORTER_LOCAL Int doSceneForName(const std::string& name) override;
+        MAGNUM_ASSIMPIMPORTER_LOCAL std::string doSceneName(UnsignedInt id) override;
         MAGNUM_ASSIMPIMPORTER_LOCAL Containers::Optional<SceneData> doScene(UnsignedInt id) override;
 
         MAGNUM_ASSIMPIMPORTER_LOCAL UnsignedInt doCameraCount() const override;
+        MAGNUM_ASSIMPIMPORTER_LOCAL Int doCameraForName(const std::string& name) override;
+        MAGNUM_ASSIMPIMPORTER_LOCAL std::string doCameraName(UnsignedInt id) override;
         MAGNUM_ASSIMPIMPORTER_LOCAL Containers::Optional<CameraData> doCamera(UnsignedInt id) override;
 
         MAGNUM_ASSIMPIMPORTER_LOCAL UnsignedInt doObject3DCount() const override;
@@ -455,6 +471,8 @@ class MAGNUM_ASSIMPIMPORTER_EXPORT AssimpImporter: public AbstractImporter {
         MAGNUM_ASSIMPIMPORTER_LOCAL Containers::Pointer<ObjectData3D> doObject3D(UnsignedInt id) override;
 
         MAGNUM_ASSIMPIMPORTER_LOCAL UnsignedInt doLightCount() const override;
+        MAGNUM_ASSIMPIMPORTER_LOCAL Int doLightForName(const std::string& name) override;
+        MAGNUM_ASSIMPIMPORTER_LOCAL std::string doLightName(UnsignedInt id) override;
         MAGNUM_ASSIMPIMPORTER_LOCAL Containers::Optional<LightData> doLight(UnsignedInt id) override;
 
         MAGNUM_ASSIMPIMPORTER_LOCAL UnsignedInt doMeshCount() const override;

src/MagnumPlugins/AssimpImporter/CMakeLists.txt

@@ -59,8 +59,22 @@ else()
     set(_ASSIMP_TRY_COMPILE_LINK_OR_INCLUDE LINK_LIBRARIES Assimp::Assimp)
 endif()
 
+# Newer versions of Assimp add C compile features that end up being propagated
+# to installed CMake targets:
+# https://github.com/assimp/assimp/commit/799384f2b85b8d3ee9c5b9e18bbe532b4dc7c63c
+# This can fail in try_compile because it uses the file extension to determine
+# the language and then doesn't look for a C compiler for the required feature.
+# CMAKE_PROJECT_[PROJECT]_INCLUDE allows us to include a script after any
+# project() calls in try_compile, which then injects a call to
+# enable_language(C). CMAKE_TRY_COMPILE is the name of the project in the
+# temporary CMakeList.txt created by try_compile:
+# https://github.com/Kitware/CMake/blob/v3.4.0/Source/cmCoreTryCompile.cxx#L313
+file(WRITE ${CMAKE_CURRENT_BINARY_DIR}/checkAssimpVersionLanguageOverride.cmake "enable_language(C)")
+# For some reason, this also needs C to be enabled in this scope
+enable_language(C)
+
 # Go through all versions of interest and pick the highest one that compiles
-foreach(_version 20201123 20190915 20151031)
+foreach(_version 20210102 20201123 20200225 20191122 20190915 20160716 20151031)
     try_compile(_works ${CMAKE_CURRENT_BINARY_DIR}
         ${CMAKE_CURRENT_SOURCE_DIR}/checkAssimpVersion.cpp
         ${_ASSIMP_TRY_COMPILE_LINK_OR_INCLUDE}
@@ -71,6 +85,8 @@ foreach(_version 20201123 20190915 20151031)
             # CORRADE_CXX_STANDARD property doesn't get passed through. So I
             # have to use an internal variable for that instead.
             ${CORRADE_CXX11_STANDARD_FLAG}
+        CMAKE_FLAGS
+            -DCMAKE_PROJECT_CMAKE_TRY_COMPILE_INCLUDE=${CMAKE_CURRENT_BINARY_DIR}/checkAssimpVersionLanguageOverride.cmake
         OUTPUT_VARIABLE _version_output)
     if(_works)
         set(ASSIMP_VERSION ${_version})