VGLSetSegment
offset = VGLSetSegment(pos + planepos);
offset = VGLSetSegment(pos);
offset = VGLSetSegment(pos);
offset = VGLSetSegment(pos);
soffset = VGLSetSegment(offset + 2);
offset = VGLSetSegment(y*VGLAdpInfo.va_line_width + x/8);
VGLSetSegment(offset);
offset = VGLSetSegment(offset);
soffset = VGLSetSegment(offset);
soffset = VGLSetSegment(offset + 1);
int VGLSetSegment(unsigned int offset);