I’m watching the tutorials on modern opengl in c++ and i’ve some trouble to understand the following line of code:

glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid *)0);

why the ‘8 * sizeof(GLfloat)’ and why ‘(GLvoid* )0’ and not just 0 ?