/**
 * @file llviewertextureanim.cpp
 * @brief LLViewerTextureAnim class implementation
 *
 * $LicenseInfo:firstyear=2003&license=viewerlgpl$
 * 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
 * $/LicenseInfo$
 */

#include "llviewerprecompiledheaders.h"

#include "llviewertextureanim.h"
#include "llvovolume.h"

#include "llmath.h"
#include "llerror.h"

std::vector<LLViewerTextureAnim*> LLViewerTextureAnim::sInstanceList;

LLViewerTextureAnim::LLViewerTextureAnim(LLVOVolume* vobj) : LLTextureAnim()
{
    mVObj = vobj;
    mLastFrame = -1.f;  // Force an update initially
    mLastTime = 0.f;
    mOffS = mOffT = 0;
    mScaleS = mScaleT = 1;
    mRot = 0;

    mInstanceIndex = static_cast<S32>(sInstanceList.size());
    sInstanceList.push_back(this);
}

LLViewerTextureAnim::~LLViewerTextureAnim()
{
    S32 end_idx = static_cast<S32>(sInstanceList.size()) - 1;

    if (end_idx != mInstanceIndex)
    {
        sInstanceList[mInstanceIndex] = sInstanceList[end_idx];
        sInstanceList[mInstanceIndex]->mInstanceIndex = mInstanceIndex;
    }

    sInstanceList.pop_back();
}

void LLViewerTextureAnim::reset()
{
    LLTextureAnim::reset();
    mTimer.reset();
}

//static
void LLViewerTextureAnim::updateClass()
{
    for (std::vector<LLViewerTextureAnim*>::iterator iter = sInstanceList.begin(); iter != sInstanceList.end(); ++iter)
    {
        (*iter)->mVObj->animateTextures();
    }
}

S32 LLViewerTextureAnim::animateTextures(F32 &off_s, F32 &off_t,
                                        F32 &scale_s, F32 &scale_t,
                                        F32 &rot)
{
    S32 result = 0;
    if (!(mMode & ON))
    {
        mLastTime = 0.f;
        mLastFrame = -1.f;
        return result;
    }


    F32 num_frames = 1.0;
    F32 full_length = 1.0;

    if (mLength)
    {
        num_frames = mLength;
    }
    else
    {
        num_frames = llmax(1.f, (F32)(mSizeX * mSizeY));
    }

    if (mMode & PING_PONG)
    {
        if (mMode & SMOOTH)
        {
            full_length = 2.f*num_frames;
        }
        else if (mMode & LOOP)
        {
            full_length = 2.f*num_frames - 2.f;
            full_length = llmax(1.f, full_length);
        }
        else
        {
            full_length = 2.f*num_frames - 1.f;
            full_length = llmax(1.f, full_length);
        }
    }
    else
    {
        full_length = num_frames;
    }


    F32 frame_counter;
    if (mMode & SMOOTH)
    {
        frame_counter = mTimer.getElapsedTimeAndResetF32() * mRate + (F32)mLastTime;
    }
    else
    {
        frame_counter = mTimer.getElapsedTimeF32() * mRate;
    }
    mLastTime = frame_counter;

    if (mMode & LOOP)
    {
        frame_counter  = fmod(frame_counter, full_length);
    }
    else
    {
        frame_counter = llmin(full_length - 1.f, frame_counter);
    }

    if (!(mMode & SMOOTH))
    {
        frame_counter = (F32)llfloor(frame_counter + 0.01f);
        // account for 0.01, we shouldn't step over full length
        frame_counter = llmin(full_length - 1.f, frame_counter);
    }

    if (mMode & PING_PONG)
    {
        if (frame_counter >= num_frames)
        {
            if (mMode & SMOOTH)
            {
                frame_counter = num_frames - (frame_counter - num_frames);
            }
            else
            {
                frame_counter = (num_frames - 1.99f) - (frame_counter - num_frames);
            }
        }
    }

    if (mMode & REVERSE)
    {
        if (mMode & SMOOTH)
        {
            frame_counter = num_frames - frame_counter;
        }
        else
        {
            frame_counter = (num_frames - 0.99f) - frame_counter;
        }
    }

    frame_counter += mStart;

    if (!(mMode & SMOOTH))
    {
        frame_counter = (F32)ll_round(frame_counter);
    }

    //
    // Now that we've calculated the frame time, do an update.
    // Will we correctly update stuff if the texture anim has
    // changed, but not the frame counter?
    //
    if (mLastFrame != frame_counter)
    {
        mLastFrame = frame_counter;
        if (mMode & ROTATE)
        {
            result |= ROTATE;
            mRot = rot = frame_counter;
        }
        else if (mMode & SCALE)
        {
            result |= SCALE;
            mScaleS = scale_s = frame_counter;
            mScaleT = scale_t = frame_counter;
        }
        else
        {
            result |= TRANSLATE;
            F32 x_frame;
            S32 y_frame;
            F32 x_pos;
            F32 y_pos;

            if (  (mSizeX)
                &&(mSizeY))
            {
                result |= SCALE;
                mScaleS = scale_s = 1.f/mSizeX;
                mScaleT = scale_t = 1.f/mSizeY;
                x_frame = fmodf(frame_counter, mSizeX);
                y_frame = (S32)(frame_counter / mSizeX);
                x_pos = x_frame * scale_s;
                y_pos = y_frame * scale_t;
                mOffS = off_s = (-0.5f + 0.5f*scale_s)+ x_pos;
                mOffT = off_t = (0.5f - 0.5f*scale_t) - y_pos;
            }
            else
            {
                mScaleS = scale_s = 1.f;
                mScaleT = scale_t = 1.f;
                x_pos = frame_counter * scale_s;
                mOffS = off_s = (-0.5f + 0.5f*scale_s)+ x_pos;
                mOffT = off_t = 0.f;
            }
        }
    }
    return result;
}