目标:(十八)中的问题55
osgEarth::TerrainOption中_tileSize默认大小为17,LOD的默认范围为0-23,这两个值的关系是什么?
还有瓦片的像素尺寸_tilePixelSize默认为256,它和_tileSize有什么关系?
和(二十一)中创建瓦片模型时默认高程网格点数257什么关系
_tileSize和_tilePixelSize是这样说明的:
osgEarth/TerrainOptions
/**
* Size of each dimension of each terrain tile, in verts. Ideally this
* will be a power of 2 plus 1, i.e.: a number X with that X = (2^Y)+1
* where Y is an integer >= 1.
*
* Default = 17.
*/
optional<int>& tileSize() { return _tileSize; }
const optional<int>& tileSize() const { return _tileSize; }
/** The size of the tile, in pixels, when using rangeMode = PIXEL_SIZE_ON_SCREEN */
optional<float>& tilePixelSize() { return _tilePixelSize; }
const optional<float>& tilePixelSize() const { return _tilePixelSize; }
/**
* The minimum tile LOD range as a factor of the tile's radius.
* Default = 7.0.
*/
optional<float>& minTileRangeFactor() { return _minTileRangeFactor; }
const optional<float>& minTileRangeFactor() const { return _minTileRangeFactor; }
/**
* The maximum level of detail to which the terrain should subdivide. If you leave this
* unset, the terrain will subdivide until the map layers stop providing data (default
* behavior). If you set a value, the terrain will stop subdividing at the specified LOD
* even if