OpenGL Programming Guide: The Official Guide to Learning OpenGL, Version 4.3, Eighth Edition

Getting Data into and out of Buffers

There are many ways to get data into and out of buffers in OpenGL. These range from explicitly providing the data, to replacing parts of the data in a buffer object with new data, to generating the data with OpenGL and recording it into the buffer object. The simplest way to get data into a buffer object is to load data into the buffer at time of allocation. This is accomplished through the use of the glBufferData() function. Here’s the prototype of glBufferData() again.

void glBufferData(GLenum target, GLsizeiptr size,                         const GLvoid *data, GLenum usage);

Allocates size bytes of storage for the buffer object bound to target. If data is non-NULL, that space is initialized with the contents ...