triangleIndices
A buffer of indices describing the triangle mesh formed by the face geometry’s vertex data.
Declaration
@property (nonatomic, readonly) const int16_t * triangleIndices;Discussion
Each 16-bit integer value in this buffer represents an index into the vertices and textureCoordinates buffers. Each set of three indices identifies the vertices that form a single triangle in the mesh. (That is, this buffer is appropriate for use as an index buffer for a triangle mesh in GPU-based rendering or creating 3D model asset files.)
Each set of three indices forms a triangle, so the number of indices in the triangleIndices buffer is three times the triangleCount value.
Face mesh topology is constant across ARFaceGeometry instances, so this buffer always describes the same arrangement of vertices. Only the vertices buffer changes between face meshes provided by an AR session, indicating the change in vertex positions as ARKit adapts the mesh to the shape and expression of the user’s face.