Metaverse Structured Data (MSD) is encoding scheme which uses Google Protocol Buffers implementation for encoding and decoding state and interaction payloads transmitted over MXP. Google Protocol Buffers .proto-files are IDL-files which are used by protogen application to create Encoding/Decoding classes. John Hurliman contributed the idea of using Google Protocol Buffers instead of XML based approach.

Application Specific MSD Schemas

• Open Metaverse - Open Metaverse schema is iterative process to define working schema for OpenSimulator and compliant systems. The schema can be viewed from source repository.

Common Data Types

// Metaverse Structured Data Types

message MsdVector3f {
required float X=1;
required float Y=2;
required float Z=3;
}

message MsdQuaternion4f {
required float X=1;
required float Y=2;
required float Z=3;
required float W=4;
}

message MsdColor4f {
required float R=1;
required float G=2;
required float B=3;
required float A=4;
}

MSD fragment types

• Object state data
• Object action data
• Object interaction request data
• Object interaction response data

Examples

This is an example of extending PerceptionEvent to carry terrain object data in compressed bitmap format:

// Terrain object extension for simple heightmap based terrains.
// Heightmap layer is scaled to fit the object are in X,Z-plane.
// Layer values are adressed in the array as follows:
// float floatValue=heightMap[x+y*width]
// Float array presenting height map is first encoded to short array as follows:
// short shortValue=(short)((floatValue-offset)*Scale)
// This is further compressed with deflate algorithm.
message OmBitmapTerrainExt {
required uint32 Width=1;
required uint32 Height=2;
required float Offset=3;
required float Scale=4;
required bytes HeightMap=5;
}