//-
// ==========================================================================
// Copyright (C) 1995 - 2005 Alias Systems Corp. and/or its licensors.  All 
// rights reserved. 
// 
// The coded instructions, statements, computer programs, and/or related 
// material (collectively the "Data") in these files are provided by Alias 
// Systems Corp. ("Alias") and/or its licensors for the exclusive use of the 
// Customer (as defined in the Alias Software License Agreement that 
// accompanies this Alias software). Such Customer has the right to use, 
// modify, and incorporate the Data into other products and to distribute such 
// products for use by end-users.
//  
// THE DATA IS PROVIDED "AS IS".  ALIAS HEREBY DISCLAIMS ALL WARRANTIES 
// RELATING TO THE DATA, INCLUDING, WITHOUT LIMITATION, ANY AND ALL EXPRESS OR 
// IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND/OR FITNESS FOR A 
// PARTICULAR PURPOSE. IN NO EVENT SHALL ALIAS BE LIABLE FOR ANY DAMAGES 
// WHATSOEVER, WHETHER DIRECT, INDIRECT, SPECIAL, OR PUNITIVE, WHETHER IN AN 
// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, OR IN EQUITY, 
// ARISING OUT OF ACCESS TO, USE OF, OR RELIANCE UPON THE DATA.
// ==========================================================================
//+

//  Description
//	The dynExprField node implements a uniform field, which allows 
//      the per particle attributes to drive the field's attributes.
//

#include <maya/MIOStream.h>
#include <maya/MVector.h>
#include <maya/MObject.h>
#include <maya/MPlug.h>
#include <maya/MDataBlock.h>
#include <maya/MFnPlugin.h>
#include <maya/MPxFieldNode.h>

#if defined(OSMac_MachO_)
#include <OpenGL/gl.h>
#else
#include <GL/gl.h>
#endif

#define McheckErr(stat, msg)		\
	if ( MS::kSuccess != stat )    	\
	{			      	\
		cerr << msg;		\
		return MS::kFailure;	\
	}

class dynExprField: public MPxFieldNode
{
public:
	dynExprField() {};
	virtual ~dynExprField() {};

	static void    *creator();
	static MStatus	initialize();

	// will compute output force.
	//
	virtual MStatus	compute( const MPlug& plug, MDataBlock& block );

	///
	virtual MStatus iconSizeAndOrigin(	GLuint& width,
						GLuint& height,
						GLuint& xbo,
						GLuint& ybo   );
	///
	virtual MStatus iconBitmap(GLubyte* bitmap);

	//
	// attributes.
	//

	// direction of the force
	//
	static MObject	mDirection;

	// Other data members
	//
        static MTypeId	id;

private:

	// methods to get attribute value.
	//
	double	magnitude(MDataBlock& block);

	MVector direction(MDataBlock& block);

	// Compute the force to apply to each particle
	void apply(MDataBlock         &block,
		   int                 receptorSize,
		   const MDoubleArray &magnitudeArray,
		   const MDoubleArray &magnitudeOwnerArray,
		   const MVectorArray &directionArray,
		   const MVectorArray &directionOwnerArray,
		   MVectorArray       &outputForce);
};