Do I need glDeleteBuffers/glGenBuffers to resize the buffer?

Programming
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1

After initializing the VBO as:

GLuint vertex_buffer;
glGenBuffers(1, &vertex_buffer);
glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer);
glBufferData(GL_ARRAY_BUFFER, data_size_in_bytes, data_vertices, GL_STATIC_DRAW);

data_vertices stores some points data. When pushing back new points and resizing data_vertices (making it larger), is it necessary to call glDeleteBuffers/glGenBuffers before glBindBuffer or just glBindBuffer?

GLuint vertex_buffer;
glDeleteBuffers(1, &vertex_buffer); // is this necessary?
glGenBuffers(1, &vertex_buffer); // is this necessary?
glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer);
glBufferData(GL_ARRAY_BUFFER, new_data_size_in_bytes, new_data_vertices, GL_STATIC_DRAW);

If glDeleteBuffers/glGenBuffers aren’t called in every update frame, some computers may experience points disappearing.

2

No, it is not necessary to call glDeleteBuffers and glGenBuffers before glBindBuffer when resizing data_vertices. You can directly bind the existing buffer using glBindBuffer and update the buffer data using glBufferData. Calling glDeleteBuffers and glGenBuffers is not required unless you want to completely delete and recreate the buffer object.