Predictive coding of texture coordinates for polygon mesh compression

A method of mesh processing, comprising:

• determining a first initial UV vertex of a first UV chart in a plurality of UV charts in a UV space for a mesh in three-dimensional (3D) space, the mesh including a plurality of 3D vertices in the 3D space that corresponds to UV vertices in the UV space, the first initial UV vertex corresponding to a first 3D vertex of the plurality of 3D vertices, the first initial UV vertex being determined from a plurality of unvisited UV vertices in the first UV chart when the first initial UV vertex is to be determined based on the plurality of unvisited UV vertices;
• performing UV coordinate predictions for first UV vertices in the first UV chart following a traversing order of the first UV vertices, the traversing order starting from the first initial UV vertex and traversing each UV vertex in the first UV chart;
• determining prediction residuals of the first UV vertices based on the UV coordinate predictions of the first UV vertices following the traversing order of the first UV vertices;
• encoding the prediction residuals of the first UV vertices into a bitstream of coded information of the mesh according to the traversing order;
• and
• encoding a first 3D index of the first 3D vertex into the bitstream of the coded information of the mesh, the first 3D index indicating the first initial UV vertex in the plurality of unvisited UV vertices.

A non-transitory computer-readable storage medium storing instructions which, when executed by a processor, cause the processor to perform an encoding method comprising:

• determining a first initial UV vertex of a first UV chart in a plurality of UV charts in a UV space for a mesh in three-dimensional (3D) space, the mesh including a plurality of 3D vertices in the 3D space that corresponds to UV vertices in the UV space, the first initial UV vertex corresponding to a first 3D vertex of the plurality of 3D vertices, the first initial UV vertex being determined from a plurality of unvisited UV vertices in the first UV chart when the first initial UV vertex is to be determined based on the plurality of unvisited UV vertices;
• performing UV coordinate predictions for first UV vertices in the first UV chart following a traversing order of the first UV vertices, the traversing order starting from the first initial UV vertex and traversing each UV vertex in the first UV chart;
• determining prediction residuals of the first UV vertices based on the UV coordinate predictions of the first UV vertices following the traversing order of the first UV vertices;
• encoding the prediction residuals of the first UV vertices into a bitstream of coded information of the mesh according to the traversing order;
• encoding a first 3D index of the first 3D vertex into the bitstream of the coded information of the mesh, the first 3D index indicating the first initial UV vertex in the plurality of unvisited UV vertices;
• and
• transmitting the encoded bitstream of the coded information of the mesh.