glTF2: import correct animation values for CUBICSPLINE

CUBICSPLINE interpolation has tangent values with the animation data.
Current import don't care this interpolation type but it will help not
to fetch tangent values instead of animation data.

Note: Assimp cannot support interpolation types yet.

code/AssetLib/glTF2/glTF2Importer.cpp

@@ -1074,9 +1074,11 @@ aiNodeAnim *CreateNodeAnim(glTF2::Asset&, Node &node, AnimationSamplers &sampler
         samplers.translation->output->ExtractData(values);
         anim->mNumPositionKeys = static_cast<uint32_t>(samplers.translation->input->count);
         anim->mPositionKeys = new aiVectorKey[anim->mNumPositionKeys];
+        unsigned int ii = (samplers.translation->interpolation == Interpolation_CUBICSPLINE) ? 1 : 0;
         for (unsigned int i = 0; i < anim->mNumPositionKeys; ++i) {
             anim->mPositionKeys[i].mTime = times[i] * kMillisecondsFromSeconds;
-            anim->mPositionKeys[i].mValue = values[i];
+            anim->mPositionKeys[i].mValue = values[ii];
+            ii += (samplers.translation->interpolation == Interpolation_CUBICSPLINE) ? 3 : 1;
         }
         delete[] times;
         delete[] values;
@@ -1096,12 +1098,14 @@ aiNodeAnim *CreateNodeAnim(glTF2::Asset&, Node &node, AnimationSamplers &sampler
         samplers.rotation->output->ExtractData(values);
         anim->mNumRotationKeys = static_cast<uint32_t>(samplers.rotation->input->count);
         anim->mRotationKeys = new aiQuatKey[anim->mNumRotationKeys];
+        unsigned int ii = (samplers.rotation->interpolation == Interpolation_CUBICSPLINE) ? 1 : 0;
         for (unsigned int i = 0; i < anim->mNumRotationKeys; ++i) {
             anim->mRotationKeys[i].mTime = times[i] * kMillisecondsFromSeconds;
-            anim->mRotationKeys[i].mValue.x = values[i].w;
-            anim->mRotationKeys[i].mValue.y = values[i].x;
-            anim->mRotationKeys[i].mValue.z = values[i].y;
-            anim->mRotationKeys[i].mValue.w = values[i].z;
+            anim->mRotationKeys[i].mValue.x = values[ii].w;
+            anim->mRotationKeys[i].mValue.y = values[ii].x;
+            anim->mRotationKeys[i].mValue.z = values[ii].y;
+            anim->mRotationKeys[i].mValue.w = values[ii].z;
+            ii += (samplers.rotation->interpolation == Interpolation_CUBICSPLINE) ? 3 : 1;
         }
         delete[] times;
         delete[] values;
@@ -1122,9 +1126,11 @@ aiNodeAnim *CreateNodeAnim(glTF2::Asset&, Node &node, AnimationSamplers &sampler
         samplers.scale->output->ExtractData(values);
         anim->mNumScalingKeys = static_cast<uint32_t>(samplers.scale->input->count);
         anim->mScalingKeys = new aiVectorKey[anim->mNumScalingKeys];
+        unsigned int ii = (samplers.scale->interpolation == Interpolation_CUBICSPLINE) ? 1 : 0;
         for (unsigned int i = 0; i < anim->mNumScalingKeys; ++i) {
             anim->mScalingKeys[i].mTime = times[i] * kMillisecondsFromSeconds;
-            anim->mScalingKeys[i].mValue = values[i];
+            anim->mScalingKeys[i].mValue = values[ii];
+            ii += (samplers.scale->interpolation == Interpolation_CUBICSPLINE) ? 3 : 1;
         }
         delete[] times;
         delete[] values;
@@ -1153,11 +1159,14 @@ aiMeshMorphAnim *CreateMeshMorphAnim(glTF2::Asset&, Node &node, AnimationSampler
         samplers.weight->output->ExtractData(values);
         anim->mNumKeys = static_cast<uint32_t>(samplers.weight->input->count);
 
-        const unsigned int numMorphs = (unsigned int)samplers.weight->output->count / anim->mNumKeys;
+        // for Interpolation_CUBICSPLINE can have more outputs
+        const unsigned int weightStride = (unsigned int)samplers.weight->output->count / anim->mNumKeys;
+        const unsigned int numMorphs = (samplers.weight->interpolation == Interpolation_CUBICSPLINE) ? weightStride - 2 : weightStride;
 
         anim->mKeys = new aiMeshMorphKey[anim->mNumKeys];
-        unsigned int k = 0u;
+        unsigned int ii = (samplers.weight->interpolation == Interpolation_CUBICSPLINE) ? 1 : 0;
         for (unsigned int i = 0u; i < anim->mNumKeys; ++i) {
+            unsigned int k = weightStride * i + ii;
             anim->mKeys[i].mTime = times[i] * kMillisecondsFromSeconds;
             anim->mKeys[i].mNumValuesAndWeights = numMorphs;
             anim->mKeys[i].mValues = new unsigned int[numMorphs];