/** 
 * @file llviewerjointattachment.h
 * @brief Implementation of LLViewerJointAttachment class
 *
 * $LicenseInfo:firstyear=2002&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2010, Linden Research, Inc.
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License only.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 * 
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 */

#ifndef LL_LLVIEWERJOINTATTACHMENT_H
#define LL_LLVIEWERJOINTATTACHMENT_H

//-----------------------------------------------------------------------------
// Header Files
//-----------------------------------------------------------------------------
#include "llviewerjoint.h"
#include "llstring.h"
#include "lluuid.h"

class LLDrawable;
class LLViewerObject;

extern const F32 MAX_ATTACHMENT_DIST;

//-----------------------------------------------------------------------------
// class LLViewerJointAttachment
//-----------------------------------------------------------------------------
class LLViewerJointAttachment :
	public LLViewerJoint
{
public:
	LLViewerJointAttachment();
	virtual ~LLViewerJointAttachment();

	//virtual U32 render( F32 pixelArea );	// Returns triangle count

	// Returns true if this object is transparent.
	// This is used to determine in which order to draw objects.
	BOOL isTransparent() override;

	// Draws the shape attached to a joint.
	// Called by render().
	U32  drawShape( F32 pixelArea, BOOL first_pass, BOOL is_dummy ) override;
	
	BOOL updateLOD(F32 pixel_area, BOOL activate) override;

	//
	// accessors
	//

	void setPieSlice(S32 pie_slice) { mPieSlice = pie_slice; }	
	void setVisibleInFirstPerson(BOOL visibility) { mVisibleInFirst = visibility; }
	BOOL getVisibleInFirstPerson() const { return mVisibleInFirst; }
	void setGroup(S32 group) { mGroup = group; }
	void setOriginalPosition(LLVector3 &position);
	void setAttachmentVisibility(BOOL visible);
	void setIsHUDAttachment(BOOL is_hud) { mIsHUDAttachment = is_hud; }
	BOOL getIsHUDAttachment() const { return mIsHUDAttachment; }

	BOOL isAnimatable() const override { return FALSE; }

	S32 getGroup() const { return mGroup; }
	S32 getPieSlice() const { return mPieSlice; }
	S32	getNumObjects() const { return mAttachedObjects.size(); }
	S32	getNumAnimatedObjects() const;

	void clampObjectPosition();

	//
	// unique methods
	//
	BOOL addObject(LLViewerObject* object);
	void removeObject(LLViewerObject *object);

	// 
	// attachments operations
	//
	BOOL isObjectAttached(const LLViewerObject *viewer_object) const;
	const LLViewerObject *getAttachedObject(const LLUUID &object_id) const;
	LLViewerObject *getAttachedObject(const LLUUID &object_id);

	// list of attachments for this joint
	typedef std::vector<LLPointer<LLViewerObject> > attachedobjs_vec_t;
	attachedobjs_vec_t mAttachedObjects;

    bool    hasChanged(const LLVector3 &pos, const LLQuaternion &rot) const
    {
        static constexpr F32 SMALL_CHANGE_DIST2(0.05f * 0.05f);
        static constexpr F32 SMALL_CHANGE_ANGL(0.225f);    // just shy of 13 degrees
        // Angle choice and LLQuaternion::almost_equal: almost_equal uses the Small Angle Approximation 
        // for cos.  The approximation diverges more than 1% at around 0.6620 radians. We are under 
        // this limit and to be honest, an error of 1% in this case is acceptable. 

        return (((pos - mLastTrackedPos).magVecSquared() > SMALL_CHANGE_DIST2) || 
            !LLQuaternion::almost_equal(rot, mLastTrackedRot, SMALL_CHANGE_ANGL));
    }

    void    setLastTracked(const LLVector3 &tracked_pos, const LLQuaternion &tracked_rot)
    {
        mLastTrackedPos = tracked_pos;
        mLastTrackedRot = tracked_rot;
    }

protected:
	void calcLOD();
	void setupDrawable(LLViewerObject *object);

private:
    BOOL                mVisibleInFirst;
    LLVector3           mOriginalPos;
    S32                 mGroup;
    BOOL                mIsHUDAttachment;
    S32                 mPieSlice;
    LLVector3           mLastTrackedPos;
    LLQuaternion        mLastTrackedRot;
};

#endif // LL_LLVIEWERJOINTATTACHMENT_H
