//绑定VBO以供使用
glGenBuffers(1, &m_VertexBuffer);
glBindBuffer(GL_ARRAY_BUFFER, m_VertexBuffer);
//加载数据到VBO
glBufferData(GL_ARRAY_BUFFER, 9 * meshNum * sizeof(float),
positionData, GL_STATIC_DRAW);
glEnableVertexAttribArray(0);//顶点坐标
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, (GLubyte *)NULL);