assimp/code/ConvertToLHProcess.h

/*
Open Asset Import Library (ASSIMP)
----------------------------------------------------------------------

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*/

/** @file  MakeLeftHandedProcess.h
 *  @brief Defines a bunch of post-processing steps to handle
 *    coordinate system conversions.
 *
 *  - LH to RH
 *  - UV origin upper-left to lower-left
 *  - face order cw to ccw 
 */
#ifndef AI_CONVERTTOLHPROCESS_H_INC
#define AI_CONVERTTOLHPROCESS_H_INC

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

struct aiMesh;
struct aiNodeAnim;

namespace Assimp	{

// -----------------------------------------------------------------------------------
/** @brief The MakeLeftHandedProcess converts all imported data to a left-handed
 *   coordinate system. 
 *
 * This implies a mirroring of the Z axis of the coordinate system. But to keep 
 * transformation matrices free from reflections we shift the reflection to other
 * places. We mirror the meshes and adapt the rotations.
 *
 * @note RH-LH and LH-RH is the same, so this class can be used for both
 */
class MakeLeftHandedProcess : public BaseProcess
{
	

public:
	MakeLeftHandedProcess();
	~MakeLeftHandedProcess();

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

	// -------------------------------------------------------------------
	void Execute( aiScene* pScene);

protected:

	// -------------------------------------------------------------------
	/** Recursively converts a node and all of its children
	 */
	void ProcessNode( aiNode* pNode, const aiMatrix4x4& pParentGlobalRotation);

	// -------------------------------------------------------------------
	/** Converts a single mesh to left handed coordinates. 
	 * This means that positions, normals and tangents are mirrored at
	 * the local Z axis and the order of all faces are inverted.
	 * @param pMesh The mesh to convert.
	 */
	void ProcessMesh( aiMesh* pMesh);

	// -------------------------------------------------------------------
	/** Converts a single material to left-handed coordinates
	 * @param pMat Material to convert
	 */
	void ProcessMaterial( aiMaterial* pMat);

	// -------------------------------------------------------------------
	/** Converts the given animation to LH coordinates. 
	 * The rotation and translation keys are transformed, the scale keys
	 * work in local space and can therefore be left untouched.
	 * @param pAnim The bone animation to transform
	 */
	void ProcessAnimation( aiNodeAnim* pAnim);
};


// ---------------------------------------------------------------------------
/** Postprocessing step to flip the face order of the imported data
 */
class FlipWindingOrderProcess : public BaseProcess
{
	friend class Importer;

public:
	/** Constructor to be privately used by Importer */
	FlipWindingOrderProcess();

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

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

	// -------------------------------------------------------------------
	void Execute( aiScene* pScene);

protected:
	void ProcessMesh( aiMesh* pMesh);
};

// ---------------------------------------------------------------------------
/** Postprocessing step to flip the UV coordinate system of the import data
 */
class FlipUVsProcess : public BaseProcess
{
	friend class Importer;

public:
	/** Constructor to be privately used by Importer */
	FlipUVsProcess();

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

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

	// -------------------------------------------------------------------
	void Execute( aiScene* pScene);

protected:
	void ProcessMesh( aiMesh* pMesh);
	void ProcessMaterial( aiMaterial* mat);
};

} // end of namespace Assimp

#endif // AI_CONVERTTOLHPROCESS_H_INC