The last record Batched3DModel3DTileContent data structure analysis, the problem with Instanced3DModel3DtileContent data structure
Instanced3DModel3DtileContent
Let’s take a look at Cesium’s layout:
BatchTable and glTF are all existing content. What makes our eyes blink is featureTable. Cesium provides Cesium3DTileFeatureTable to package.
Accounting is a specific featureTable content. It is not difficult to understand that the instantiation content of this data is Position. Cesium realizes the instantiation of Model through ModelInstanceCollection. Focus on the derivation principle of Position instantiation matrix to strengthen the depth of understanding.
Above is the corresponding Shader and associated Uniform fragment. Czm_instanced_model is the passed instantiation matrix. Czm_instanced_nodeTransform is not discussed. Is the matrix corresponding to the relative positions of the parent and child nodes. According to Shader’s formula, it is not difficult to conclude that A_position is the relative position of the center point of the relative model, while CZM_Instanced_model is the matrix of the center point of the current single model corresponding to the center point of the model set.
Check the Instanced3DModel3DTileContent instantiation of the corresponding matrix computation, data storage or center of each model of latitude and longitude information, internally to the relative matrix relative collection center.
So that’s it for Content
Finally, draw lessons from the source code analysis of “chicken silk” big guy