VBO - 用于存储顶点数据的Buffer Object。
VAO - 用于组织VBO的对象。
Generic Vertex Attribute - 通用顶点属性。
For example, the VertexAttribPointer command copies the value of ARRAY_BUFFER_BINDING (the queriable name of the buffer binding corresponding to the target ARRAY_BUFFER) to the client state variable VERTEX_ATTRIB_ARRAY_BUFFER_BINDING for the specified index.
VertexAttribPointer命令将ARRAY_BUFFER_BINDING的值（ARRAY_BUFFER挂节点上绑定的Buffer的句柄）拷贝到客户端状态中制定索引对应的变量VERTEX_ATTRIB_ARRAY_BUFFER_BINDING中。
The command
int GetAttribLocation( uint program, const char *name );
returns the generic attribute index that the attribute variable named name was bound to when the program object named program was last linked.
GetAttribLocation返回通用属性的索引。