C++ Vector::reserve方法代码示例

void ConePrimitiveShape::BitmapExtent(float epsilon,
	GfxTL::AABox< GfxTL::Vector2Df > *bbox,
	MiscLib::Vector< std::pair< float, float > > *params,
	size_t *uextent, size_t *vextent)
{
	*uextent = std::ceil((bbox->Max()[0] - bbox->Min()[0]) / epsilon); // no wrappig along u direction
	*vextent = std::ceil((bbox->Max()[1] - bbox->Min()[1]) / epsilon) + 1; // add one for wrapping
	if((*vextent) * (*uextent) > 1e6 && m_cone.Angle() < float(M_PI / 4))
	{
		// try to reparameterize
		// try to find cut in the outer regions
		MiscLib::Vector< float > angularParams;//(params->size());
		angularParams.reserve(params->size());
		float outer = 3.f * std::max(abs(bbox->Min()[0]), abs(bbox->Max()[0])) / 4.f;
		for(size_t i = 0; i < params->size(); ++i)
			if((*params)[i].first > outer)
				angularParams.push_back(((*params)[i].second
					/ m_cone.RadiusAtLength((*params)[i].first)) + float(M_PI));
		std::sort(angularParams.begin(), angularParams.end());
		// try to find a large gap
		float maxGap = 0;
		float lower, upper;
		for(size_t i = 1; i < angularParams.size(); ++i)
		{
			float gap = angularParams[i] - angularParams[i - 1];
			if(gap > maxGap)
			{
				maxGap = gap;
				lower = angularParams[i - 1];
				upper = angularParams[i];
			}
		}
		// reparameterize with new angular cut
		float newCut = (lower + upper) / 2.f;
		m_cone.RotateAngularDirection(newCut);
		bbox->Min()[1] = std::numeric_limits< float >::infinity();
		bbox->Max()[1] = -std::numeric_limits< float >::infinity();
		for(size_t i = 0; i < params->size(); ++i)
		{
			float r = m_cone.RadiusAtLength((*params)[i].first);
			(*params)[i].second = ((*params)[i].second / r) + float(M_PI) - newCut;
			if((*params)[i].second < 0)
				(*params)[i].second = 2 * float(M_PI) + (*params)[i].second;
			(*params)[i].second = ((*params)[i].second - float(M_PI)) * r;
			if((*params)[i].second < bbox->Min()[1])
				bbox->Min()[1] = (*params)[i].second;
			if((*params)[i].second > bbox->Max()[1])
				bbox->Max()[1] = (*params)[i].second;
		}
		*vextent = std::floor((bbox->Max()[1] - bbox->Min()[1]) / epsilon) + 1;
	}
}

void Components(const MiscLib::Vector< char > &bitmap,
	size_t uextent, size_t vextent, bool uwrap, bool vwrap,
	MiscLib::Vector< int > *componentsImg,
	MiscLib::Vector< std::pair< int, size_t > > *labels)
{
	componentsImg->resize(uextent * vextent);
	MiscLib::Vector< std::pair< int, size_t > > tempLabels;
	tempLabels.reserve(componentsImg->size() / 2 + 1); // this is the maximum of possible tempLabels
	tempLabels.push_back(std::make_pair(0, size_t(0)));
	// use an eight neighborhood
	// first row is special
	// first pixel is special
	// wrapping does not make sense in the first row: no pixels have been
	// assigned components yet
	int curLabel = 0;
	if(bitmap[0])
	{
		(*componentsImg)[0] = ++curLabel;
		tempLabels.push_back(std::make_pair(curLabel, size_t(1)));
	}
	else
	{
		(*componentsImg)[0] = 0;
		++tempLabels[0].second;
	}
	// handle first row
	for(size_t i = 1; i < uextent; ++i)
	{
		// in the first row only the previous pixel has to be considered
		if(bitmap[i])
		{
			if((*componentsImg)[i - 1])
			{
				(*componentsImg)[i] = (*componentsImg)[i - 1];
				++tempLabels[(*componentsImg)[i]].second;
			}
			else
			{
				(*componentsImg)[i] = ++curLabel;
				tempLabels.push_back(std::make_pair(curLabel, size_t(1)));
			}
		}
		else
		{
			(*componentsImg)[i] = 0;
			++tempLabels[0].second;
		}
	}
	size_t prevRow, row = 0;
	size_t jend = vwrap? vextent - 1 : vextent;
	for(size_t j = 1; j < jend; ++j)
	{
		prevRow = row;
		row = prevRow + uextent;
		// first pixel in row gets different treatment
		if(bitmap[row])
		{
			if((*componentsImg)[prevRow]) // pixel above in component?
			{
				(*componentsImg)[row] = (*componentsImg)[prevRow];
				++tempLabels[(*componentsImg)[row]].second;
			}
			else
			{
				int n[2];
				n[0] = (*componentsImg)[prevRow + 1];
				if(uwrap)
					n[1] = (*componentsImg)[prevRow + uextent - 1];
				(*componentsImg)[row] = Label(n, uwrap? 2 : 1, &curLabel,
					&tempLabels);
			}
		}
		else
		{
			(*componentsImg)[row] = 0;
			++tempLabels[0].second;
		}
		for(size_t i = 1; i < uextent - 1; ++i)
		{
			if(!bitmap[row + i])
			{
				(*componentsImg)[row + i] = 0;
				++tempLabels[0].second;
				continue;
			}
			int n[4];
			n[0] = (*componentsImg)[row + i - 1];
			n[1] = (*componentsImg)[prevRow + i - 1];
			n[2] = (*componentsImg)[prevRow + i];
			n[3] = (*componentsImg)[prevRow + i + 1];
			(*componentsImg)[row + i] = Label(n, 4, &curLabel, &tempLabels);
		}
		// last pixel in the row
		if(!bitmap[row + uextent - 1])
		{
			(*componentsImg)[row + uextent - 1] = 0;
			++tempLabels[0].second;
			continue;
		}
		int n[5];
//.........这里部分代码省略.........