/**
 * @file llhudicon.cpp
 * @brief LLHUDIcon class implementation
 *
 * $LicenseInfo:firstyear=2006&license=viewerlgpl$
 * 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 "llhudicon.h"

#include "llgl.h"
#include "llrender.h"

#include "llviewerobject.h"
#include "lldrawable.h"
#include "llvector4a.h"
#include "llviewercamera.h"
#include "llviewertexture.h"
#include "llviewerwindow.h"

//-----------------------------------------------------------------------------
// Local consts
//-----------------------------------------------------------------------------
const F32 ANIM_TIME = 0.4f;
const F32 DIST_START_FADE = 15.f;
const F32 DIST_END_FADE = 30.f;
const F32 MAX_VISIBLE_TIME = 15.f;
const F32 FADE_OUT_TIME = 1.f;

//-----------------------------------------------------------------------------
// Utility functions
//-----------------------------------------------------------------------------
static F32 calc_bouncy_animation(F32 x)
{
    return -(cosf(x * F_PI * 2.5f - F_PI_BY_TWO))*(0.4f + x * -0.1f) + x * 1.3f;
}


//-----------------------------------------------------------------------------
// static declarations
//-----------------------------------------------------------------------------
LLHUDIcon::icon_instance_t LLHUDIcon::sIconInstances;

LLHUDIcon::LLHUDIcon(const U8 type) :
            LLHUDObject(type),
            mImagep(NULL),
            mScale(0.1f),
            mHidden(false)
{
    sIconInstances.push_back(this);
}

LLHUDIcon::~LLHUDIcon()
{
    mImagep = NULL;
}

void LLHUDIcon::render()
{
    LLGLSUIDefault texture_state;
    LLGLDepthTest gls_depth(GL_TRUE);
    //LLGLDisable gls_stencil(GL_STENCIL_TEST);

    if (mHidden)
        return;

    if (mSourceObject.isNull() || mImagep.isNull())
    {
        markDead();
        return;
    }

    LLVector3 obj_position = mSourceObject->getRenderPosition();

    // put icon above object, and in front
    // RN: don't use drawable radius, it's fricking HUGE
    LLViewerCamera* camera = LLViewerCamera::getInstance();
    LLVector3 icon_relative_pos = (camera->getUpAxis() * ~mSourceObject->getRenderRotation());
    icon_relative_pos.abs();

    F32 distance_scale = llmin(mSourceObject->getScale().mV[VX] / icon_relative_pos.mV[VX],
        mSourceObject->getScale().mV[VY] / icon_relative_pos.mV[VY],
        mSourceObject->getScale().mV[VZ] / icon_relative_pos.mV[VZ]);
    F32 up_distance = 0.5f * distance_scale;
    LLVector3 icon_position = obj_position + (up_distance * camera->getUpAxis()) * 1.2f;

    LLVector3 icon_to_cam = LLViewerCamera::getInstance()->getOrigin() - icon_position;
    icon_to_cam.normVec();

    icon_position += icon_to_cam * mSourceObject->mDrawable->getRadius() * 1.1f;

    mDistance = dist_vec(icon_position, camera->getOrigin());

    F32 alpha_factor = clamp_rescale(mDistance, DIST_START_FADE, DIST_END_FADE, 1.f, 0.f);

    LLVector3 x_pixel_vec;
    LLVector3 y_pixel_vec;

    camera->getPixelVectors(icon_position, y_pixel_vec, x_pixel_vec);

    F32 scale_factor = 1.f;
    if (mAnimTimer.getElapsedTimeF32() < ANIM_TIME)
    {
        scale_factor = llmax(0.f, calc_bouncy_animation(mAnimTimer.getElapsedTimeF32() / ANIM_TIME));
    }

    F32 time_elapsed = mLifeTimer.getElapsedTimeF32();
    if (time_elapsed > MAX_VISIBLE_TIME)
    {
        markDead();
        return;
    }

    if (time_elapsed > MAX_VISIBLE_TIME - FADE_OUT_TIME)
    {
        alpha_factor *= clamp_rescale(time_elapsed, MAX_VISIBLE_TIME - FADE_OUT_TIME, MAX_VISIBLE_TIME, 1.f, 0.f);
    }

    F32 image_aspect = (F32)mImagep->getFullWidth() / (F32)mImagep->getFullHeight() ;
    LLVector3 x_scale = image_aspect * (F32)gViewerWindow->getWindowHeightScaled() * mScale * scale_factor * x_pixel_vec;
    LLVector3 y_scale = (F32)gViewerWindow->getWindowHeightScaled() * mScale * scale_factor * y_pixel_vec;

    LLVector3 lower_left = icon_position - (x_scale * 0.5f);
    LLVector3 lower_right = icon_position + (x_scale * 0.5f);
    LLVector3 upper_left = icon_position - (x_scale * 0.5f) + y_scale;
    LLVector3 upper_right = icon_position + (x_scale * 0.5f) + y_scale;

    {
        LLColor4 icon_color = LLColor4::white;
        icon_color.mV[VALPHA] = alpha_factor;
        gGL.color4fv(icon_color.mV);
        gGL.getTexUnit(0)->bind(mImagep);
    }

    gGL.begin(LLRender::TRIANGLES);
    {
        gGL.texCoord2f(0.f, 1.f);
        gGL.vertex3fv(upper_left.mV);
        gGL.texCoord2f(0.f, 0.f);
        gGL.vertex3fv(lower_left.mV);
        gGL.texCoord2f(1.f, 0.f);
        gGL.vertex3fv(lower_right.mV);

        gGL.texCoord2f(0.f, 1.f);
        gGL.vertex3fv(upper_left.mV);
        gGL.texCoord2f(1.f, 0.f);
        gGL.vertex3fv(lower_right.mV);
        gGL.texCoord2f(1.f, 1.f);
        gGL.vertex3fv(upper_right.mV);
    }
    gGL.end();
}

void LLHUDIcon::setImage(LLViewerTexture* imagep)
{
    mImagep = imagep;
    mImagep->setAddressMode(LLTexUnit::TAM_CLAMP);
}

void LLHUDIcon::setScale(F32 fraction_of_fov)
{
    mScale = fraction_of_fov;
}

void LLHUDIcon::markDead()
{
    if (mSourceObject)
    {
        mSourceObject->clearIcon();
    }
    LLHUDObject::markDead();
}

bool LLHUDIcon::lineSegmentIntersect(const LLVector4a& start, const LLVector4a& end, LLVector4a* intersection)
{
    if (mHidden)
        return false;

    if (mSourceObject.isNull() || mImagep.isNull())
    {
        markDead();
        return false;
    }

    LLVector3 obj_position = mSourceObject->getRenderPosition();

    // put icon above object, and in front
    // RN: don't use drawable radius, it's fricking HUGE
    LLViewerCamera* camera = LLViewerCamera::getInstance();
    LLVector3 icon_relative_pos = (camera->getUpAxis() * ~mSourceObject->getRenderRotation());
    icon_relative_pos.abs();

    F32 distance_scale = llmin(mSourceObject->getScale().mV[VX] / icon_relative_pos.mV[VX],
        mSourceObject->getScale().mV[VY] / icon_relative_pos.mV[VY],
        mSourceObject->getScale().mV[VZ] / icon_relative_pos.mV[VZ]);
    F32 up_distance = 0.5f * distance_scale;
    LLVector3 icon_position = obj_position + (up_distance * camera->getUpAxis()) * 1.2f;

    LLVector3 icon_to_cam = LLViewerCamera::getInstance()->getOrigin() - icon_position;
    icon_to_cam.normVec();

    icon_position += icon_to_cam * mSourceObject->mDrawable->getRadius() * 1.1f;

    mDistance = dist_vec(icon_position, camera->getOrigin());

    LLVector3 x_pixel_vec;
    LLVector3 y_pixel_vec;

    camera->getPixelVectors(icon_position, y_pixel_vec, x_pixel_vec);

    F32 scale_factor = 1.f;
    if (mAnimTimer.getElapsedTimeF32() < ANIM_TIME)
    {
        scale_factor = llmax(0.f, calc_bouncy_animation(mAnimTimer.getElapsedTimeF32() / ANIM_TIME));
    }

    F32 time_elapsed = mLifeTimer.getElapsedTimeF32();
    if (time_elapsed > MAX_VISIBLE_TIME)
    {
        markDead();
        return false;
    }

    F32 image_aspect = (F32)mImagep->getFullWidth() / (F32)mImagep->getFullHeight() ;
    LLVector3 x_scale = image_aspect * (F32)gViewerWindow->getWindowHeightScaled() * mScale * scale_factor * x_pixel_vec;
    LLVector3 y_scale = (F32)gViewerWindow->getWindowHeightScaled() * mScale * scale_factor * y_pixel_vec;

    LLVector4a x_scalea;
    LLVector4a icon_positiona;
    LLVector4a y_scalea;

    x_scalea.load3(x_scale.mV);
    x_scalea.mul(0.5f);
    y_scalea.load3(y_scale.mV);

    icon_positiona.load3(icon_position.mV);

    LLVector4a lower_left;
    lower_left.setSub(icon_positiona, x_scalea);
    LLVector4a lower_right;
    lower_right.setAdd(icon_positiona, x_scalea);
    LLVector4a upper_left;
    upper_left.setAdd(lower_left, y_scalea);
    LLVector4a upper_right;
    upper_right.setAdd(lower_right, y_scalea);

    LLVector4a dir;
    dir.setSub(end, start);

    F32 a,b,t;

    if (LLTriangleRayIntersect(upper_right, upper_left, lower_right, start, dir, a,b,t) ||
        LLTriangleRayIntersect(upper_left, lower_left, lower_right, start, dir, a,b,t))
    {
        if (intersection)
        {
            dir.mul(t);
            intersection->setAdd(start, dir);
        }
        return true;
    }

    return false;
}

//static
LLHUDIcon* LLHUDIcon::lineSegmentIntersectAll(const LLVector4a& start, const LLVector4a& end, LLVector4a* intersection)
{
    icon_instance_t::iterator icon_it;

    LLVector4a local_end = end;
    LLVector4a position;

    LLHUDIcon* ret = NULL;
    for(icon_it = sIconInstances.begin(); icon_it != sIconInstances.end(); ++icon_it)
    {
        LLHUDIcon* icon = *icon_it;
        if (icon->lineSegmentIntersect(start, local_end, &position))
        {
            ret = icon;
            if (intersection)
            {
                *intersection = position;
            }
            local_end = position;
        }
    }

    return ret;
}


 //static
void LLHUDIcon::updateAll()
{
    cleanupDeadIcons();
}

//static
bool LLHUDIcon::iconsNearby()
{
    return !sIconInstances.empty();
}

//static
void LLHUDIcon::cleanupDeadIcons()
{
    icon_instance_t::iterator icon_it;

    icon_instance_t icons_to_erase;
    for(icon_it = sIconInstances.begin(); icon_it != sIconInstances.end(); ++icon_it)
    {
        if ((*icon_it)->mDead)
        {
            icons_to_erase.push_back(*icon_it);
        }
    }

    for(icon_it = icons_to_erase.begin(); icon_it != icons_to_erase.end(); ++icon_it)
    {
        icon_instance_t::iterator found_it = std::find(sIconInstances.begin(), sIconInstances.end(), *icon_it);
        if (found_it != sIconInstances.end())
        {
            sIconInstances.erase(found_it);
        }
    }
}

//static
S32 LLHUDIcon::getNumInstances()
{
    return (S32)sIconInstances.size();
}