Why should we load textures AFTER creating windows in OpenGL?

Question

In my situation

glutInitWindowSize(w_walker*8, h_walker);
glutCreateWindow("walker");
loadTexture("./fighter512.png");

worked but

loadTexture("./fighter512.png");
glutInitWindowSize(w_walker*8, h_walker);
glutCreateWindow("walker");

no. Why?

Answer 1

Often, with some implementations of the / OpenGL drivers, the window-creating action has the side effect of determining where the memory for textures, off-screen buffers and the window itself will actually be stored, and therefore how large it will be.

Without creating a window (or, more precisely, a display context), it is difficult (i.e. impossible) to determine where to place the texture after loading.

Answer 2

OpenGL OpenGL. GLUT OpenGL . PBuffers OpenGL . X11/GLX PBuffers ; Windows OpenGL, PBuffer, OpenGL. PBuffer OpenGL, .