/**
 * @file llsprite.cpp
 * @brief LLSprite class implementation
 *
 * $LicenseInfo:firstyear=2000&license=viewerlgpl$
 * 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
 * $/LicenseInfo$
 */

/* -*- c++ -*-
 *  Notes:
 *      PR - Should add a creator that can take a pointer rather than handle for streaming
 *      object textures.
 *      PR - Need to add support for lit/non-lit conditions, set normals?
 */

#include "llviewerprecompiledheaders.h"

#include <llglheaders.h>

#include "llsprite.h"

#include <cmath>

#include "lldrawable.h"
#include "llface.h"
#include "llviewercamera.h"
#include "llviewertexturelist.h"

LLVector3 LLSprite::sCameraUp(0.0f,0.0f,1.0f);
LLVector3 LLSprite::sCameraRight(1.0f,0.0f,0.0f);
LLVector3 LLSprite::sCameraPosition(0.f, 0.f, 0.f);
LLVector3 LLSprite::sNormal(0.0f,0.0f,0.0f);

//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

// A simple initialization
LLSprite::LLSprite(const LLUUID &image_uuid) :
    mImageID(image_uuid),
    mImagep(NULL),
    mPitch(0.f),
    mYaw(0.f),
    mPosition(0.0f, 0.0f, 0.0f),
    mFollow(true),
    mUseCameraUp(true),
    mColor(0.5f, 0.5f, 0.5f, 1.0f),
    mTexMode(GL_REPLACE)
{
    setSize(1.0f, 1.0f);
}

//////////////////////////////////////////////////////////////////////
LLSprite::~LLSprite()
{
}

void LLSprite::updateFace(LLFace &face)
{
    LLViewerCamera &camera = *LLViewerCamera::getInstance();

    // First, figure out how many vertices/indices we need.
    U32 num_vertices, num_indices;

    // Get the total number of vertices and indices
    if (mFollow)
    {
        num_vertices = 4;
        num_indices = 6;
    }
    else
    {
        num_vertices = 4;
        num_indices = 12;
    }

    face.setSize(num_vertices, num_indices);

    if (mFollow)
    {
        sCameraUp = camera.getUpAxis();
        sCameraRight = -camera.getLeftAxis();
        sCameraPosition = camera.getOrigin();
        sNormal = -camera.getAtAxis();
        if (mUseCameraUp)
        {
            // these need to live here because the height/width may change between render calls
            mScaledUp = sCameraUp;
            mScaledRight = sCameraRight;

            mScaledUp *= mHeightDiv2;
            mScaledRight *= mWidthDiv2;

            mA = mPosition + mScaledRight + mScaledUp;
            mB = mPosition - mScaledRight + mScaledUp;
            mC = mPosition - mScaledRight - mScaledUp;
            mD = mPosition + mScaledRight - mScaledUp;
        }
        else
        {
            // The up vector is perpendicular to the camera vector...
            LLVector3 camera_vec = mPosition - sCameraPosition;
            mScaledRight = camera_vec % LLVector3(0.f, 0.f, 1.f);
            mScaledUp = -(camera_vec % mScaledRight);
            mScaledUp.normalize();
            mScaledRight.normalize();
            mScaledUp *= mHeightDiv2;
            mScaledRight *= mWidthDiv2;

            mA = mPosition + mScaledRight + mScaledUp;
            mB = mPosition - mScaledRight + mScaledUp;
            mC = mPosition - mScaledRight - mScaledUp;
            mD = mPosition + mScaledRight - mScaledUp;
        }
    }
    else
    {
        // this is equivalent to how it was done before. . .
        // we need to establish a way to
        // identify the orientation of a particular sprite rather than
        // just banging it in on the x,z plane if it's not following the camera.

        LLVector3 x_axis;
        LLVector3 y_axis;

        F32 dot = sNormal * LLVector3(0.f, 1.f, 0.f);
        if (dot == 1.f || dot == -1.f)
        {
            x_axis.setVec(1.f, 0.f, 0.f);
            y_axis.setVec(0.f, 1.f, 0.f);
        }
        else
        {
            x_axis = sNormal % LLVector3(0.f, -1.f, 0.f);
            x_axis.normalize();

            y_axis = sNormal % x_axis;
        }

        LLQuaternion yaw_rot(mYaw, sNormal);

        // rotate axes by specified yaw
        x_axis = x_axis * yaw_rot;
        y_axis = y_axis * yaw_rot;

        // rescale axes by width and height of sprite
        x_axis = x_axis * mWidthDiv2;
        y_axis = y_axis *  mHeightDiv2;

        mA = -x_axis + y_axis;
        mB = x_axis + y_axis;
        mC = x_axis - y_axis;
        mD = -x_axis - y_axis;

        mA += mPosition;
        mB += mPosition;
        mC += mPosition;
        mD += mPosition;
    }

    face.setFaceColor(mColor);

    LLStrider<LLVector3> verticesp;
    LLStrider<LLVector3> normalsp;
    LLStrider<LLVector2> tex_coordsp;
    LLStrider<U16> indicesp;
    U16 index_offset;

    // Setup face
    if (!face.getVertexBuffer())
    {
        LLVertexBuffer* buff = new LLVertexBuffer(LLVertexBuffer::MAP_VERTEX |
                                                LLVertexBuffer::MAP_TEXCOORD0 );
        buff->allocateBuffer(4, 12);
        face.setGeomIndex(0);
        face.setIndicesIndex(0);
        face.setVertexBuffer(buff);
    }

    index_offset = face.getGeometry(verticesp,normalsp,tex_coordsp, indicesp);

    *tex_coordsp = LLVector2(0.f, 0.f);
    *verticesp = mC;
    tex_coordsp++;
    verticesp++;

    *tex_coordsp = LLVector2(0.f, 1.f);
    *verticesp = mB;
    tex_coordsp++;
    verticesp++;

    *tex_coordsp = LLVector2(1.f, 1.f);
    *verticesp = mA;
    tex_coordsp++;
    verticesp++;

    *tex_coordsp = LLVector2(1.f, 0.0f);
    *verticesp = mD;
    tex_coordsp++;
    verticesp++;

    // Generate indices, since they're easy.
    // Just a series of quads.
    *indicesp++ = index_offset;
    *indicesp++ = 2 + index_offset;
    *indicesp++ = 1 + index_offset;

    *indicesp++ = index_offset;
    *indicesp++ = 3 + index_offset;
    *indicesp++ = 2 + index_offset;

    if (!mFollow)
    {
        *indicesp++ = 0 + index_offset;
        *indicesp++ = 1 + index_offset;
        *indicesp++ = 2 + index_offset;
        *indicesp++ = 0 + index_offset;
        *indicesp++ = 2 + index_offset;
        *indicesp++ = 3 + index_offset;
    }

    face.getVertexBuffer()->unmapBuffer();
    face.mCenterAgent = mPosition;
}

void LLSprite::setPosition(const LLVector3 &position)
{
    mPosition = position;
}


void LLSprite::setPitch(const F32 pitch)
{
    mPitch = pitch;
}


void LLSprite::setSize(const F32 width, const F32 height)
{
    mWidth = width;
    mHeight = height;
    mWidthDiv2 = width/2.0f;
    mHeightDiv2 = height/2.0f;
}

void LLSprite::setYaw(F32 yaw)
{
    mYaw = yaw;
}

void LLSprite::setFollow(const bool follow)
{
    mFollow = follow;
}

void LLSprite::setUseCameraUp(const bool use_up)
{
    mUseCameraUp = use_up;
}

void LLSprite::setTexMode(const LLGLenum mode)
{
    mTexMode = mode;
}

void LLSprite::setColor(const LLColor4 &color)
{
    mColor = color;
}

void LLSprite::setColor(const F32 r, const F32 g, const F32 b, const F32 a)
{
    mColor.setVec(r, g, b, a);
}