void Screen::set_ortho_viewport(const Extents& extents)
{
int screenHeight = m_extents->bottom() - m_extents->top();
const int& x1 = extents.left(), y1 = extents.top(), x2 = extents.right(), y2 = extents.bottom();
glViewport(x1, screenHeight - y2, x2-x1, y2-y1);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluOrtho2D(-1, x2+1-x1, y2+1-y1, -1);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}
void Screen::set_persp_viewport(const Extents& extents, double fovY, double zNear, double zFar)
{
int screenHeight = m_extents->bottom() - m_extents->top();
const int& x1 = extents.left(), y1 = extents.top(), x2 = extents.right(), y2 = extents.bottom();
glViewport(x1, screenHeight - y2, x2-x1, y2-y1);
double width = x2 - x1, height = y2 - y1;
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(fovY, width / height, zNear, zFar);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}