Probably something to do with not flipping the backbuffer, most likely an easy fix.
I know nothing about OpenGl, but anyway i tried to investigate the problem.
I read that when you are using multiple viewports with OpenGL, you should use the instruction SwapBuffers(). So i tried in the GL3screen.cpp file, to add this method in the screen_redraw() function :
for (view_current = 0; view_current < 8; view_current++)
screen_set_viewport(view_xport[vc], view_yport[vc], view_wport[vc], view_hport[vc]);
clear_view(view_xview[vc], view_yview[vc], view_wview[vc], view_hview[vc], view_angle[vc], background_showcolor && draw_backs);
I try to use this method, but i've a message which declares it's not available. ('SwapBuffers' was not declared in this scope). I know it's a noob question, but if someone can help, i will appreciate.
Edit : it seems SwapBuffers is not included in glew.h, but it's available in glew.c, so i tried to include this file also, but it was a mistake as ENIGMA is stuck when compiling the sources. (c.f glew manual : 'The simpler but less flexible way is to include glew.h and glew.c into your project')