Function dtBuildTileCacheContours

3rdparty/recast/DetourTileCacheBuilder.cpp:748–838

TODO: move this somewhere else, once the layer meshing is done.

// TODO: move this somewhere else, once the layer meshing is done.
dtStatus dtBuildTileCacheContours(dtTileCacheAlloc* alloc,
								  dtTileCacheLayer& layer,
								  const int walkableClimb, 	const float maxError,
								  dtTileCacheContourSet& lcset)
{
	dtAssert(alloc);

	const int w = (int)layer.header->width;
	const int h = (int)layer.header->height;
	
	lcset.nconts = layer.regCount;
	lcset.conts = (dtTileCacheContour*)alloc->alloc(sizeof(dtTileCacheContour)*lcset.nconts);
	if (!lcset.conts)
		return DT_FAILURE | DT_OUT_OF_MEMORY;
	memset(lcset.conts, 0, sizeof(dtTileCacheContour)*lcset.nconts);
	
	// Allocate temp buffer for contour tracing.
	const int maxTempVerts = (w+h)*2 * 2; // Twice around the layer.
	
	dtFixedArray<unsigned char> tempVerts(alloc, maxTempVerts*4);
	if (!tempVerts)
		return DT_FAILURE | DT_OUT_OF_MEMORY;
	
	dtFixedArray<unsigned short> tempPoly(alloc, maxTempVerts);
	if (!tempPoly)
		return DT_FAILURE | DT_OUT_OF_MEMORY;

	dtTempContour temp(tempVerts, maxTempVerts, tempPoly, maxTempVerts);
	
	// Find contours.
	for (int y = 0; y < h; ++y)
	{
		for (int x = 0; x < w; ++x)
		{
			const int idx = x+y*w;
			const unsigned char ri = layer.regs[idx];
			if (ri == 0xff)
				continue;
			
			dtTileCacheContour& cont = lcset.conts[ri];
			
			if (cont.nverts > 0)
				continue;
			
			cont.reg = ri;
			cont.area = layer.areas[idx];
			
			if (!walkContour(layer, x, y, temp))
			{
				// Too complex contour.
				// Note: If you hit here ofte, try increasing 'maxTempVerts'.
				return DT_FAILURE | DT_BUFFER_TOO_SMALL;
			}
			
			simplifyContour(temp, maxError);
			
			// Store contour.
			cont.nverts = temp.nverts;