assimp/code/OptimizeMeshes.h

/*
Open Asset Import Library (ASSIMP)
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*/

/** @file  OptimizeMeshes.h
 *  @brief Declares a post processing step to join meshes, if possible 
 */
#ifndef AI_OPTIMIZEMESHESPROCESS_H_INC
#define AI_OPTIMIZEMESHESPROCESS_H_INC

#include "BaseProcess.h"
#include "../include/aiTypes.h"

struct aiMesh;
class OptimizeMeshesProcessTest;
namespace Assimp	{

// ---------------------------------------------------------------------------
/** @brief Postprocessing step to optimize mesh usage
 *
 *  The implementation looks for meshes that could be joined and joins them.
 *  Usually this will reduce the number of drawcalls.
 *
 *  @note Instanced meshes are currently not processed.
 */
class ASSIMP_API OptimizeMeshesProcess : public BaseProcess
{
	friend class Importer;
	friend class ::OptimizeMeshesProcessTest;

protected:
	/** Constructor to be privately used by Importer */
	OptimizeMeshesProcess();

	/** Destructor, private as well */
	~OptimizeMeshesProcess();


	/** @brief Internal utility to store additional mesh info
	 */
	struct MeshInfo
	{
		MeshInfo()
			:	instance_cnt  (0)
			,	vertex_format (0)
			,	output_id	  (0xffffffff)
		{}

		//! Number of times this mesh is referenced
		unsigned int instance_cnt;

		//! Vertex format id
		unsigned int vertex_format;

		//! Output ID
		unsigned int output_id;
	};

public:
	// -------------------------------------------------------------------
	bool IsActive( unsigned int pFlags) const;

	// -------------------------------------------------------------------
	void Execute( aiScene* pScene);
	
	// -------------------------------------------------------------------
	void SetupProperties(const Importer* pImp);


	// -------------------------------------------------------------------
	/** @brief Specify whether you want meshes with different 
	 *   primitive types to be merged as well.
	 *
	 *  IsActive() sets this property automatically to true if the
	 *  aiProcess_SortByPType flag is found.
	 */
	void EnablePrimitiveTypeSorting(bool enable) {
		pts = enable;
	}

	// Getter 
	bool IsPrimitiveTypeSortingEnabled () const {
		return pts;
	}


	// -------------------------------------------------------------------
	/** @brief Specify a maximum size of a single output mesh.
	 *  
	 *  If a single input mesh already exceeds this limit, it won't
	 *  be splitted.
	 *  @param verts Maximum number of vertices per mesh
	 *  @param faces Maximum number of faces per mesh
	 */
	void SetPreferredMeshSizeLimit (unsigned int verts, unsigned int faces)
	{
		max_verts = verts;
		max_faces = faces;
	}


protected:

	// -------------------------------------------------------------------
	/** @brief Do the actual optimization on all meshes of this node
	 *  @param pNode Node we're working with
	 */
	void ProcessNode( aiNode* pNode);

	// -------------------------------------------------------------------
	/** @brief Returns true if b can be joined with a
	 *
	 *  @param verts Number of output verts up to now
	 *  @param faces Number of output faces up to now
	 */
	bool CanJoin ( unsigned int a, unsigned int b,
		unsigned int verts, unsigned int faces );

	// -------------------------------------------------------------------
	/** @brief Find instanced meshes, for the moment we're excluding
	 *   them from all optimizations
	 */
	void FindInstancedMeshes (aiNode* pNode);

private:

	//! Scene we're working with
	aiScene* mScene;

	//! Per mesh info
	std::vector<MeshInfo> meshes;

	//! Next output mesh
	aiMesh* mesh;

	//! Output meshes
	std::vector<aiMesh*> output;

	//! @see EnablePrimitiveTypeSorting
	mutable bool pts;

	//! @see SetPreferredMeshSizeLimit
	mutable unsigned int max_verts,max_faces;

	//! Temporary storage
	std::vector<aiMesh*> merge_list;
};

} // end of namespace Assimp

#endif // AI_CALCTANGENTSPROCESS_H_INC