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author | Tycho <work.tycho+git@gmail.com> | 2014-05-25 19:02:33 +0200 |
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committer | Tycho <work.tycho+git@gmail.com> | 2014-05-25 19:02:33 +0200 |
commit | 8133efd7f9def01b81ef2a52c05d8ec5b7f89632 (patch) | |
tree | a56f6889aea8de8759fab87abdee2eef778873ed /src/Generating/GridStructGen.h | |
parent | Fixed bug in freeing NULL pointers (diff) | |
parent | inject TestGlobals.h correctly (diff) | |
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Diffstat (limited to 'src/Generating/GridStructGen.h')
-rw-r--r-- | src/Generating/GridStructGen.h | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/src/Generating/GridStructGen.h b/src/Generating/GridStructGen.h new file mode 100644 index 000000000..234cc75c5 --- /dev/null +++ b/src/Generating/GridStructGen.h @@ -0,0 +1,124 @@ + +// GridStructGen.h + +// Declares the cGridStructGen class representing a common base class for structure generators that place structures in a semi-random grid + + + + + +#pragma once + +#include "ComposableGenerator.h" + + + + + +/** Generates structures in a semi-random grid. +Defines a grid in the XZ space with predefined cell size in each direction. Each cell then receives exactly +one structure (provided by the descendant class). The structure is placed within the cell, but doesn't need +to be bounded by the cell, it can be well outside the cell; the generator uses the MaxStructureSize parameter +to determine how far away from the cell the structure can be at most. +This class provides a cache for the structures generated for successive chunks and manages that cache. It +also provides the cFinishGen override that uses the cache to actually generate the structure into chunk data. + +After generating each chunk the cache is checked for size, each item in the cache has a cost associated with +it and the cache is trimmed (from its least-recently-used end) so that the sum of the cost in the cache is +less than m_MaxCacheSize + +To use this class, declare a descendant class that implements the overridable methods, then create an +instance of that class. The descendant must provide the CreateStructure() function that is called to generate +a structure at the specific grid cell. + +The descendant must use a specific cStructure descendant to provide the actual structure that gets generated. +The structure must provide the DrawIntoChunk() function that generates the structure into the chunk data, and +can override the GetCacheCost() function that returns the cost of that structure in the cache. +*/ +class cGridStructGen : + public cFinishGen +{ +public: + cGridStructGen( + int a_Seed, + int a_GridSizeX, int a_GridSizeZ, + int a_MaxStructureSizeX, int a_MaxStructureSizeZ, + size_t a_MaxCacheSize + ); + +protected: + /** Represents a single structure that occupies the grid point. Knows how to draw itself into a chunk. */ + class cStructure + { + public: + /** The origin (the coords of the gridpoint for which the structure is generated) */ + int m_OriginX, m_OriginZ; + + + /** Creates a structure that has its originset at the specified coords. */ + cStructure (int a_OriginX, int a_OriginZ) : + m_OriginX(a_OriginX), + m_OriginZ(a_OriginZ) + { + } + + // Force a virtual destructor in descendants: + virtual ~cStructure() {} + + /** Draws self into the specified chunk */ + virtual void DrawIntoChunk(cChunkDesc & a_ChunkDesc) = 0; + + /** Returns the cost of keeping this structure in the cache */ + virtual size_t GetCacheCost(void) const { return 1; } + } ; + typedef SharedPtr<cStructure> cStructurePtr; + typedef std::list<cStructurePtr> cStructurePtrs; + + + /** Seed for generating the semi-random grid. */ + int m_Seed; + + /** The size of each grid's cell in the X axis */ + int m_GridSizeX; + + /** The size of each grid's cell in the Z axis */ + int m_GridSizeZ; + + /** Maximum theoretical size of the structure in the X axis. + This limits the structures considered for a single chunk, so the lesser the number, the better performance. + Structures large than this may get cropped. */ + int m_MaxStructureSizeX; + + /** Maximum theoretical size of the structure in the Z axis. + This limits the structures considered for a single chunk, so the lesser the number, the better performance. + Structures large than this may get cropped. */ + int m_MaxStructureSizeZ; + + /** Maximum allowed sum of costs for items in the cache. Items that are over this cost are removed from the + cache, oldest-first */ + size_t m_MaxCacheSize; + + /** Cache for the most recently generated structures, ordered by the recentness. */ + cStructurePtrs m_Cache; + + + /** Clears everything from the cache */ + void ClearCache(void); + + /** Returns all structures that may intersect the given chunk. + The structures are considered as intersecting iff their bounding box (defined by m_MaxStructureSize) + around their gridpoint intersects the chunk. */ + void GetStructuresForChunk(int a_ChunkX, int a_ChunkZ, cStructurePtrs & a_Structures); + + // cFinishGen overrides: + virtual void GenFinish(cChunkDesc & a_ChunkDesc) override; + + // Functions for the descendants to override: + /** Create a new structure at the specified gridpoint */ + virtual cStructurePtr CreateStructure(int a_OriginX, int a_OriginZ) = 0; +} ; + + + + + |