MeshTools: recognize & ignore morph targets in compile().

No builtin support for these at the moment.

src/Magnum/MeshTools/Compile.cpp

@@ -83,6 +83,10 @@ GL::Mesh compileInternal(const Trade::MeshData& meshData, GL::Buffer&& indices,
     UnsignedInt weightAttributeCount = 0;
     #endif
 
+    /* All morph target attributes are ignored now, count them and print just a
+       single warning for all */
+    UnsignedInt morphTargetAttributeCount = 0;
+
     for(UnsignedInt i = 0; i != meshData.attributeCount(); ++i) {
         auto addAttribute = [&](GL::DynamicAttribute attribute, std::size_t offset) {
             /* Ensure each attribute gets bound only once -- so for example
@@ -125,6 +129,13 @@ GL::Mesh compileInternal(const Trade::MeshData& meshData, GL::Buffer&& indices,
             continue;
         }
 
+        /* No builtin support for morph targets yet, count them and print a
+           single warning at the end */
+        if(meshData.attributeMorphTargetId(i) != -1) {
+            ++morphTargetAttributeCount;
+            continue;
+        }
+
         switch(meshData.attributeName(i)) {
             case Trade::MeshAttribute::Position:
                 /* Pick 3D position always, the format will properly reduce it
@@ -220,6 +231,9 @@ GL::Mesh compileInternal(const Trade::MeshData& meshData, GL::Buffer&& indices,
             Warning{} << "MeshTools::compile(): ignoring unknown/unsupported attribute" << meshData.attributeName(i);
     }
 
+    if(morphTargetAttributeCount && !(flags & CompileFlag::NoWarnOnCustomAttributes))
+        Warning{} << "MeshTools::compile(): ignoring" << morphTargetAttributeCount << "morph target attributes";
+
     #ifndef MAGNUM_TARGET_GLES2
     CORRADE_INTERNAL_ASSERT(jointIdAttributeCount == weightAttributeCount);
     #endif

src/Magnum/MeshTools/Compile.h

@@ -73,10 +73,10 @@ enum class CompileFlag: UnsignedByte {
     GenerateSmoothNormals = 1 << 1,
 
     /**
-     * By default, @ref compile() warns when it encounters custom attributes
-     * and attributes with implementation-specific format, as those get ignored
-     * by it. If you're binding those manually with
-     * @ref compile(const Trade::MeshData&, GL::Buffer&, GL::Buffer&) or
+     * By default, @ref compile() warns when it encounters custom attributes,
+     * morph target attributes and attributes with an implementation-specific
+     * format, as those get ignored by it. If you're binding those manually
+     * with @ref compile(const Trade::MeshData&, GL::Buffer&, GL::Buffer&) or
      * handling them in some other way on the application side already, use
      * this flag to suppress the warning messages.
      * @m_since{2020,06}

src/Magnum/MeshTools/Test/CompileGLTest.cpp

@@ -118,6 +118,7 @@ struct CompileGLTest: GL::OpenGLTester {
     void conflictingAttributes();
     void unsupportedIndexStride();
 
+    void morphTargetAttributes();
     void customAttribute();
     void unsupportedAttribute();
     void unsupportedAttributeStride();
@@ -473,7 +474,8 @@ CompileGLTest::CompileGLTest() {
 
     addTests({&CompileGLTest::unsupportedIndexStride});
 
-    addInstancedTests({&CompileGLTest::customAttribute,
+    addInstancedTests({&CompileGLTest::morphTargetAttributes,
+                       &CompileGLTest::customAttribute,
                        &CompileGLTest::unsupportedAttribute},
         Containers::arraySize(CustomAttributeWarningData));
 
@@ -1562,6 +1564,30 @@ void CompileGLTest::unsupportedIndexStride() {
         "MeshTools::compile(): MeshIndexType::UnsignedShort with stride of 4 bytes isn't supported by OpenGL\n");
 }
 
+void CompileGLTest::morphTargetAttributes() {
+    auto&& instanceData = CustomAttributeWarningData[testCaseInstanceId()];
+    setTestCaseDescription(instanceData.name);
+
+    Vector3 vertexData[2]{};
+    Trade::MeshData data{MeshPrimitive::Triangles, {}, vertexData, {
+        Trade::MeshAttributeData{Trade::MeshAttribute::Position,
+            Containers::arrayView(vertexData)},
+        Trade::MeshAttributeData{Trade::MeshAttribute::Color,
+            Containers::arrayView(vertexData), 37},
+        Trade::MeshAttributeData{Trade::MeshAttribute::Position,
+            Containers::arrayView(vertexData), 26},
+    }};
+
+    std::ostringstream out;
+    Warning redirectError{&out};
+    if(instanceData.flags)
+        MeshTools::compile(data, instanceData.flags);
+    else
+        MeshTools::compile(data);
+    CORRADE_COMPARE(out.str(), instanceData.flags ? "" :
+        "MeshTools::compile(): ignoring 2 morph target attributes\n");
+}
+
 void CompileGLTest::customAttribute() {
     auto&& instanceData = CustomAttributeWarningData[testCaseInstanceId()];
     setTestCaseDescription(instanceData.name);