Method cache

src/Geoscape/Globe.cpp:947–987

* Caches a set of polygons. * @param polygons Pointer to list of polygons. * @param cache Pointer to cache. */

 * @param cache Pointer to cache.
 */
void Globe::cache(std::list<Polygon*> *polygons, std::list<Polygon*> *cache)
{
	// Clear existing cache
	for (std::list<Polygon*>::iterator i = cache->begin(); i != cache->end(); ++i)
	{
		delete *i;
	}
	cache->clear();

	// Pre-calculate values to cache
	for (std::list<Polygon*>::iterator i = polygons->begin(); i != polygons->end(); ++i)
	{
		// Is quad on the back face?
		double closest = 0.0;
		double z;
		double furthest = 0.0;
		for (int j = 0; j < (*i)->getPoints(); ++j)
		{
			z = cos(_cenLat) * cos((*i)->getLatitude(j)) * cos((*i)->getLongitude(j) - _cenLon) + sin(_cenLat) * sin((*i)->getLatitude(j));
			if (z > closest)
				closest = z;
			else if (z < furthest)
				furthest = z;
		}
		if (-furthest > closest)
			continue;

		Polygon* p = new Polygon(**i);

		// Convert coordinates
		for (int j = 0; j < p->getPoints(); ++j)
		{
			Sint16 x, y;
			polarToCart(p->getLongitude(j), p->getLatitude(j), &x, &y);
			p->setX(j, x);
			p->setY(j, y);
		}

		cache->push_back(p);
	}
}

/**
 * Replaces a certain amount of colors in the palette of the globe.