/*------------------------------------------------------------

Iwa_PNPerspectiveFx

 render perspective noise pattern.

------------------------------------------------------------*/

#include "iwa_pnperspectivefx.h"

#include "trop.h"

#include "tparamuiconcept.h"

#include "iwa_fresnel.h"

#include "iwa_simplexnoise.h"

#include "iwa_noise1234.h"

#include <vector></vector>

namespace {

#ifndef M_PI

const double M_PI = 3.1415926535897932384626433832795;

#endif

inline double dot(double3 a, double3 b) {

  return a.x * b.x + a.y * b.y + a.z * b.z;

}

inline double3 cross(double3 a, double3 b) {

  double3 ret = {a.y * b.z - a.z * b.y, a.z * b.x - a.x * b.z,

                 a.x * b.y - a.y * b.x};

  return ret;

}

inline double3 normalize(double3 v) {

  double length = std::sqrt(v.x * v.x + v.y * v.y + v.z * v.z);

  double3 ret   = {v.x / length, v.y / length, v.z / length};

  return ret;

}

double getFresnel(double deg) {

  if (deg < 0.0) return 0.0;

  if (deg >= 90.0) return 1.0;

  int index    = (int)std::floor(deg);

  double ratio = deg - (double)index;

  return fresnel[index] * (1.0 - ratio) + fresnel[index + 1] * ratio;

}

}  // namespace

//------------------------------------------------------------

template <typename pixel="" raster,="" typename=""></typename>

void Iwa_PNPerspectiveFx::setOutputRaster(double4 *srcMem, const RASTER dstRas,

                                          TDimensionI dim, int drawLevel,

                                          const bool alp_rend_sw) {

  typename PIXEL::Channel halfChan =

      (typename PIXEL::Channel)(PIXEL::maxChannelValue / 2);

  if (alp_rend_sw)

    dstRas->fill(PIXEL(halfChan, halfChan, halfChan, halfChan));

  else

    dstRas->fill(PIXEL(halfChan, halfChan, halfChan));

  double4 *chan_p = srcMem;

  for (int j = 0; j < drawLevel; j++) {

    PIXEL *pix = dstRas->pixels(j);

    for (int i = 0; i < dstRas->getLx(); i++, chan_p++, pix++) {

      double val;

      val    = (*chan_p).x * (double)PIXEL::maxChannelValue + 0.5;

      pix->r = (typename PIXEL::Channel)((val > (double)PIXEL::maxChannelValue)

                                             ? (double)PIXEL::maxChannelValue

                                             : val);

      val    = (*chan_p).y * (double)PIXEL::maxChannelValue + 0.5;

      pix->g = (typename PIXEL::Channel)((val > (double)PIXEL::maxChannelValue)

                                             ? (double)PIXEL::maxChannelValue

                                             : val);

      val    = (*chan_p).z * (double)PIXEL::maxChannelValue + 0.5;

      pix->b = (typename PIXEL::Channel)((val > (double)PIXEL::maxChannelValue)

                                             ? (double)PIXEL::maxChannelValue

                                             : val);

      val    = (*chan_p).w * (double)PIXEL::maxChannelValue + 0.5;

      pix->m = (typename PIXEL::Channel)((val > (double)PIXEL::maxChannelValue)

                                             ? (double)PIXEL::maxChannelValue

                                             : val);

    }

  }

}

template <>

void Iwa_PNPerspectiveFx::setOutputRaster<trasterfp, tpixelf="">(</trasterfp,>

    double4 *srcMem, const TRasterFP dstRas, TDimensionI dim, int drawLevel,

    const bool alp_rend_sw) {

  if (alp_rend_sw)

    dstRas->fill(TPixelF(0.5f, 0.5f, 0.5f, 0.5f));

  else

    dstRas->fill(TPixelF(0.5f, 0.5f, 0.5f));

  double4 *chan_p = srcMem;

  for (int j = 0; j < drawLevel; j++) {

    TPixelF *pix = dstRas->pixels(j);

    for (int i = 0; i < dstRas->getLx(); i++, chan_p++, pix++) {

      pix->r = (float)(*chan_p).x;

      pix->g = (float)(*chan_p).y;

      pix->b = (float)(*chan_p).z;

      pix->m = std::min((float)(*chan_p).w, 1.f);

    }

  }

}

//------------------------------------------------------------

// obtain parameters

void Iwa_PNPerspectiveFx::getPNParameters(TTile &tile, double frame,

                                          const TRenderSettings &settings,

                                          PN_Params ¶ms,

                                          TDimensionI &dimOut) {

  params.renderMode = (PN_Params::RenderMode)m_renderMode->getValue();

  params.noiseType  = (PN_Params::NoiseType)m_noiseType->getValue();

  params.size       = m_size->getValue(frame);

  // adjust size of Simplex Noise to be with the same density as Perlin Noise

  if (params.noiseType == PN_Params::Simplex) params.size *= std::sqrt(2.0);

  params.octaves     = m_octaves->getValue() + 1;

  params.offset      = m_offset->getValue(frame);

  params.p_intensity = m_persistance_intensity->getValue(frame);

  params.p_size      = m_persistance_size->getValue(frame);

  params.p_offset    = m_persistance_offset->getValue(frame);

  params.eyeLevel    = m_eyeLevel->getValue(frame);

  params.alp_rend_sw = m_alpha_rendering->getValue();

  params.waveHeight  = m_waveHeight->getValue(frame);

  double fov = m_fov->getValue(frame);

  TAffine aff  = settings.m_affine;

  double scale = 1.0 / std::sqrt(std::abs(aff.det()));

  params.aff   = TScale(scale) * TTranslation(tile.m_pos);

  params.time        = m_evolution->getValue(frame) * 0.05;

  params.p_evolution = m_persistance_evolution->getValue(frame);

  TPointD eyePoint =

      aff * params.eyeLevel - (tile.m_pos + tile.getRaster()->getCenterD());

  double eyeHeight = eyePoint.y;

  // distance from the bottom of the render region to the eye level

  params.drawLevel = (int)((double)dimOut.ly / 2.0 + eyeHeight);

  if (params.drawLevel > dimOut.ly) params.drawLevel = dimOut.ly;

  //------------------------------------------------------------

  int camHeight = settings.m_cameraBox.getLy();

  TPointD vec_p0p1((double)camHeight * params.aff.a12,

                   (double)camHeight * params.aff.a22);

  params.fy_2 =

      std::sqrt(vec_p0p1.x * vec_p0p1.x + vec_p0p1.y * vec_p0p1.y) / 2.0;

  double fov_radian_2 = (fov / 2.0) * M_PI_180;

  // distance from the camera to the center of projection plane

  double D = params.fy_2 / std::tan(fov_radian_2);

  // distance from the camera to the projected point of the horizon

  params.A = std::sqrt(params.eyeLevel.y * params.eyeLevel.y + D * D);

  // angle between horizon and the vector [ camera center - bottom of the camera

  // frame ]

  double theta = fov_radian_2 + std::asin(params.eyeLevel.y / params.A);

  double M = params.fy_2 / std::sin(fov_radian_2);

  params.cam_pos = double3{0.0, -M * std::cos(theta), M * std::sin(theta)};

  // compute normalize range

  params.base_fresnel_ref = 0.0;

  params.top_fresnel_ref  = 1.0;

  if (params.renderMode == PN_Params::Fresnel &&

      m_normalize_fresnel->getValue()) {

    double phi              = 90.0 - theta * M_180_PI;

    params.base_fresnel_ref = getFresnel(phi);

    // frsnel value at the upper-side corner of the camera frame

    double fx_2 =

        params.fy_2 * (double)settings.m_cameraBox.getLx() / (double)camHeight;

    double side_A    = std::sqrt(fx_2 * fx_2 + params.A * params.A);

    double top_theta = -fov_radian_2 + std::asin(params.eyeLevel.y / side_A);

    phi              = 90.0 - top_theta * M_180_PI;

    params.top_fresnel_ref = getFresnel(phi);

    double marginRatio = m_normalize_margin->getValue(frame);

    // adding margin

    double margin =

        (params.top_fresnel_ref - params.base_fresnel_ref) * marginRatio;

    params.base_fresnel_ref = std::max(0.0, params.base_fresnel_ref - margin);

    params.top_fresnel_ref  = std::min(1.0, params.top_fresnel_ref + margin);

  }

  // for normalizing intensity

  double intensity = 2.0;  // from -1 to 1

  params.int_sum   = 0.0;

  for (int o = 0; o < params.octaves; o++) {

    params.int_sum += intensity;

    intensity *= params.p_intensity;

  }

}

//------------------------------------------------------------

Iwa_PNPerspectiveFx::Iwa_PNPerspectiveFx()

    : m_renderMode(new TIntEnumParam(PN_Params::Noise, "Noise"))

    , m_noiseType(new TIntEnumParam(PN_Params::Perlin, "Perlin Noise"))

    , m_size(10.0)

    , m_evolution(0.0)

    , m_octaves(new TIntEnumParam(0, "1"))

    , m_offset(TPointD(0, 0))

    , m_persistance_intensity(0.5)

    , m_persistance_size(0.5)

    , m_persistance_evolution(0.5)

    , m_persistance_offset(0.5)

    , m_fov(30)

    , m_eyeLevel(TPointD(0, 0))

    , m_alpha_rendering(true)

    , m_waveHeight(10.0)

    , m_normalize_fresnel(false)

    , m_normalize_margin(0.1) {

  bindParam(this, "renderMode", m_renderMode);

  bindParam(this, "noiseType", m_noiseType);

  bindParam(this, "size", m_size);

  bindParam(this, "evolution", m_evolution);

  bindParam(this, "octaves", m_octaves);

  bindParam(this, "offset", m_offset);

  bindParam(this, "persistance_intensity", m_persistance_intensity);

  bindParam(this, "persistance_size", m_persistance_size);

  bindParam(this, "persistance_evolution", m_persistance_evolution);

  bindParam(this, "persistance_offset", m_persistance_offset);

  bindParam(this, "fov", m_fov);

  bindParam(this, "eyeLevel", m_eyeLevel);

  bindParam(this, "alpha_rendering", m_alpha_rendering);

  bindParam(this, "waveHeight", m_waveHeight);

  bindParam(this, "normalize_fresnel", m_normalize_fresnel);

  bindParam(this, "normalize_margin", m_normalize_margin);

  m_noiseType->addItem(PN_Params::Simplex, "Simplex Noise");

  m_renderMode->addItem(PN_Params::Noise_NoResample, "Noise (no resampled)");

  m_renderMode->addItem(PN_Params::WarpHV, "Warp HV offset");

  m_renderMode->addItem(PN_Params::WarpHV2, "Warp HV offset 2");

  m_renderMode->addItem(PN_Params::Fresnel, "Fresnel reflectivity");

  m_size->setMeasureName("fxLength");

  m_size->setValueRange(0.0, 1000.0);

  m_octaves->addItem(1, "2");

  m_octaves->addItem(2, "3");

  m_octaves->addItem(3, "4");

  m_octaves->addItem(4, "5");

  m_octaves->addItem(5, "6");

  m_octaves->addItem(6, "7");

  m_octaves->addItem(7, "8");

  m_octaves->addItem(8, "9");

  m_octaves->addItem(9, "10");

  m_persistance_intensity->setValueRange(0.1, 2.0);

  m_persistance_size->setValueRange(0.1, 2.0);

  m_persistance_evolution->setValueRange(0.1, 2.0);

  m_persistance_offset->setValueRange(0.1, 2.0);

  m_fov->setValueRange(10, 90);

  m_eyeLevel->getX()->setMeasureName("fxLength");

  m_eyeLevel->getY()->setMeasureName("fxLength");

  m_waveHeight->setMeasureName("fxLength");

  m_waveHeight->setValueRange(1.0, 100.0);

  m_normalize_margin->setValueRange(0.0, 3.0);

  enableComputeInFloat(true);

}

//------------------------------------------------------------

bool Iwa_PNPerspectiveFx::doGetBBox(double frame, TRectD &bBox,

                                    const TRenderSettings &info) {

  bBox = TConsts::infiniteRectD;

  return true;

}

//------------------------------------------------------------

bool Iwa_PNPerspectiveFx::canHandle(const TRenderSettings &info, double frame) {

  return false;

}

//------------------------------------------------------------

void Iwa_PNPerspectiveFx::doCompute(TTile &tile, double frame,

                                    const TRenderSettings &settings) {

  if (!((TRaster32P)tile.getRaster()) && !((TRaster64P)tile.getRaster()) &&

      !((TRasterFP)tile.getRaster())) {

    throw TRopException("unsupported input pixel type");

  }

  TDimensionI dimOut(tile.getRaster()->getLx(), tile.getRaster()->getLy());

  // obtain parameters

  PN_Params pnParams;

  getPNParameters(tile, frame, settings, pnParams, dimOut);

  // return if the horizon is below the rendering area

  if (pnParams.drawLevel < 0) {

    tile.getRaster()->clear();

    return;

  }

  double evolution   = m_evolution->getValue(frame);

  double p_evolution = m_persistance_evolution->getValue(frame);

  double4 *out_host;

  // allocate buffer

  TRasterGR8P out_host_ras(sizeof(double4) * dimOut.lx, pnParams.drawLevel);

  out_host_ras->lock();

  out_host = (double4 *)out_host_ras->getRawData();

  doCompute_CPU(frame, settings, out_host, dimOut, pnParams);

  tile.getRaster()->clear();

  TRaster32P outRas32 = (TRaster32P)tile.getRaster();

  TRaster64P outRas64 = (TRaster64P)tile.getRaster();

  TRasterFP outRasF   = (TRasterFP)tile.getRaster();

  if (outRas32)

    setOutputRaster<traster32p, tpixel32="">(</traster32p,>

        out_host, outRas32, dimOut, pnParams.drawLevel, pnParams.alp_rend_sw);

  else if (outRas64)

    setOutputRaster<traster64p, tpixel64="">(</traster64p,>

        out_host, outRas64, dimOut, pnParams.drawLevel, pnParams.alp_rend_sw);

  else if (outRasF)

    setOutputRaster<trasterfp, tpixelf="">(</trasterfp,>

        out_host, outRasF, dimOut, pnParams.drawLevel, pnParams.alp_rend_sw);

  out_host_ras->unlock();

}

//------------------------------------------------------------

void Iwa_PNPerspectiveFx::doCompute_CPU(double frame,

                                        const TRenderSettings &settings,

                                        double4 *out_host, TDimensionI &dimOut,

                                        PN_Params &pnParams) {

  if (pnParams.renderMode == PN_Params::Noise ||

      pnParams.renderMode == PN_Params::Noise_NoResample) {

    calcPerinNoise_CPU(out_host, dimOut, pnParams,

                       pnParams.renderMode == PN_Params::Noise);

  } else if (pnParams.renderMode == PN_Params::WarpHV ||

             pnParams.renderMode == PN_Params::Fresnel ||

             pnParams.renderMode == PN_Params::WarpHV2) {

    calcPNNormal_CPU(out_host, dimOut, pnParams);

    if (pnParams.renderMode == PN_Params::WarpHV2) {

      calcPNNormal_CPU(out_host, dimOut, pnParams, true);

    }

  }

}

//------------------------------------------------------------

// render for 2 Noise modes

void Iwa_PNPerspectiveFx::calcPerinNoise_CPU(double4 *out_host,

                                             TDimensionI &dimOut, PN_Params &p,

                                             bool doResample) {

  int reso       = (doResample) ? 10 : 1;

  double4 *out_p = out_host;

  // compute for each pixel

  for (int yy = 0; yy < p.drawLevel; yy++) {

    for (int xx = 0; xx < dimOut.lx; xx++, out_p++) {

      double val_sum = 0.0;

      int count      = 0;

      // for each sampling points

      for (int tt = 0; tt < reso; tt++) {

        for (int ss = 0; ss < reso; ss++) {

          TPointD tmpPixPos(

              (double)xx - 0.5 + ((double)ss + 0.5) / (double)reso,

              (double)yy - 0.5 + ((double)tt + 0.5) / (double)reso);

          TPointD screenPos = p.aff * tmpPixPos;

          // compute coordinate on the noise plane

          TPointD noisePos;

          noisePos.x = -(p.eyeLevel.y + p.fy_2) * (screenPos.x - p.eyeLevel.x) /

                           (screenPos.y - p.eyeLevel.y) +

                       p.eyeLevel.x;

          noisePos.y =

              (p.fy_2 + screenPos.y) * p.A / (p.eyeLevel.y - screenPos.y);

          double tmpVal           = 0.5;

          double currentSize      = p.size;

          TPointD currentOffset   = p.offset;

          double currentIntensity = 1.0;

          double currentEvolution = p.time;

          // sum noise values

          for (int o = 0; o < p.octaves; o++) {

            TPointD currentNoisePos =

                (noisePos - currentOffset) * (1.0 / currentSize);

            if (p.noiseType == PN_Params::Perlin) {

              tmpVal += currentIntensity *

                        Noise1234::noise(currentNoisePos.x, currentNoisePos.y,

                                         currentEvolution) /

                        p.int_sum;

            } else {  // Simplex case

              tmpVal +=

                  currentIntensity *

                  SimplexNoise::noise(currentNoisePos.x, currentNoisePos.y,

                                      currentEvolution) /

                  p.int_sum;

            }

            currentSize *= p.p_size;

            currentOffset.x *= p.p_offset;

            currentOffset.y *= p.p_offset;

            currentIntensity *= p.p_intensity;

            currentEvolution *= p.p_evolution;

          }

          val_sum += tmpVal;

          count += 1;

        }

      }

      double val = val_sum / (double)count;

      (*out_p).x = val;

      (*out_p).y = val;

      (*out_p).z = val;

      if (p.alp_rend_sw)  // clamp

        (*out_p).w = (val < 0.0) ? 0.0 : ((val > 1.0) ? 1.0 : val);

      else

        (*out_p).w = 1.0;

    }

  }

}

//------------------------------------------------------------

// render WarpHV / Fresnel modes

void Iwa_PNPerspectiveFx::calcPNNormal_CPU(double4 *out_host,

                                           TDimensionI &dimOut, PN_Params &p,

                                           bool isSubWave) {

  double4 *out_p = out_host;

  // compute for each pixel

  for (int yy = 0; yy < p.drawLevel; yy++) {

    for (int xx = 0; xx < dimOut.lx; xx++, out_p++) {

      TPointD screenPos = p.aff * TPointD((double)xx, (double)yy);

      // compute coordinate on the noise plane

      TPointD noisePos;

      noisePos.x = -(p.eyeLevel.y + p.fy_2) * (screenPos.x - p.eyeLevel.x) /

                       (screenPos.y - p.eyeLevel.y) +

                   p.eyeLevel.x;

      noisePos.y = (p.fy_2 + screenPos.y) * p.A / (p.eyeLevel.y - screenPos.y);

      double gradient[2];  // 0 : horizontal 1 : vertical

      double delta = 0.001;

      for (int hv = 0; hv < 2; hv++) {

        // initialize gradient

        gradient[hv] = 0.0;

        // compute offset of sampling position

        TPointD neighborNoisePos[2] = {

            TPointD(noisePos.x - ((hv == 0) ? delta : 0.0),

                    noisePos.y - ((hv == 0) ? 0.0 : delta)),

            TPointD(noisePos.x + ((hv == 0) ? delta : 0.0),

                    noisePos.y + ((hv == 0) ? 0.0 : delta))};

        double currentSize      = p.size;

        TPointD currentOffset   = p.offset;

        double currentIntensity = 1.0;

        double currentEvolution = (isSubWave) ? p.time + 100.0 : p.time;

        // for each generation

        for (int o = 0; o < p.octaves; o++, currentSize *= p.p_size,

                 currentOffset.x *= p.p_offset, currentOffset.y *= p.p_offset,

                 currentIntensity *= p.p_intensity) {

          // compute offset noise position

          TPointD currentOffsetNoisePos[2];

          for (int mp = 0; mp < 2; mp++)

            currentOffsetNoisePos[mp] =

                (neighborNoisePos[mp] - currentOffset) * (1.0 / currentSize);

          // sum noise values differences

          double noiseDiff;

          // Perlin Noise

          if (p.noiseType == PN_Params::Perlin) {

            noiseDiff =

                Noise1234::noise(currentOffsetNoisePos[1].x,

                                 currentOffsetNoisePos[1].y, currentEvolution) -

                Noise1234::noise(currentOffsetNoisePos[0].x,

                                 currentOffsetNoisePos[0].y, currentEvolution);

          } else {  // Simplex

            // compute cell indexes

            CellIds neighborIds[2] = {

                SimplexNoise::getCellIds(currentOffsetNoisePos[0].x,

                                         currentOffsetNoisePos[0].y,

                                         currentEvolution),

                SimplexNoise::getCellIds(currentOffsetNoisePos[1].x,

                                         currentOffsetNoisePos[1].y,

                                         currentEvolution)};

            // simply compute difference if points are in the same cell

            if (neighborIds[0] == neighborIds[1]) {

              noiseDiff = SimplexNoise::noise(currentOffsetNoisePos[1].x,

                                              currentOffsetNoisePos[1].y,

                                              currentEvolution) -

                          SimplexNoise::noise(currentOffsetNoisePos[0].x,

                                              currentOffsetNoisePos[0].y,

                                              currentEvolution);

            }

            // use center cell id if points are in the different cells

            else {

              TPointD currentCenterNoisePos =

                  (noisePos - currentOffset) * (1.0 / currentSize);

              CellIds centerIds = SimplexNoise::getCellIds(

                  currentCenterNoisePos.x, currentCenterNoisePos.y,

                  currentEvolution);

              if (neighborIds[0] == centerIds) {

                noiseDiff = SimplexNoise::noise(currentCenterNoisePos.x,

                                                currentCenterNoisePos.y,

                                                currentEvolution) -

                            SimplexNoise::noise(currentOffsetNoisePos[0].x,

                                                currentOffsetNoisePos[0].y,

                                                currentEvolution);

              } else  // if(neighborIds[1] == centerIds)

              {

                noiseDiff = SimplexNoise::noise(currentOffsetNoisePos[1].x,

                                                currentOffsetNoisePos[1].y,

                                                currentEvolution) -

                            SimplexNoise::noise(currentCenterNoisePos.x,

                                                currentCenterNoisePos.y,

                                                currentEvolution);

              }

              // multiply the difference

              // 片端→中心の変位を使っているので、片端→片端に合わせて変位を2倍する

              noiseDiff *= 2.0;

            }

          }

          // sum gradient

          gradient[hv] += currentIntensity * noiseDiff / p.int_sum;

          currentEvolution *= p.p_evolution;

        }

      }

      // compute neighbor vectors

      double3 vec_x  = {delta * 2, 0.0, gradient[0] * p.waveHeight};

      double3 vec_y  = {0.0, delta * 2, gradient[1] * p.waveHeight};

      double3 normal = normalize(cross(vec_x, vec_y));

      // camera to the center of projection plane

      double3 cam_vec = {noisePos.x - p.cam_pos.x, noisePos.y - p.cam_pos.y,

                         -p.cam_pos.z};

      cam_vec         = normalize(cam_vec);

      if (p.renderMode == PN_Params::WarpHV ||

          p.renderMode == PN_Params::WarpHV2) {

        // reflected vector from the plane

        double alpha        = dot(normal, cam_vec);

        double3 reflect_cam = {

            2.0 * alpha * normal.x - cam_vec.x,

            2.0 * alpha * normal.y - cam_vec.y,

            2.0 * alpha * normal.z -

                cam_vec.z};  // the length of this vector should be 1

        // reflection vector if the plane is flat

        double3 reflect_cam_mirror = {cam_vec.x, cam_vec.y, -cam_vec.z};

        // compute the angle difference

        // between the range from -PI/2 to PI/2

        double angle_h = std::atan(reflect_cam.x / reflect_cam.y) -

                         std::atan(reflect_cam_mirror.x / reflect_cam_mirror.y);

        double angle_v = std::atan(reflect_cam.z / reflect_cam.y) -

                         std::atan(reflect_cam_mirror.z / reflect_cam_mirror.y);

        // maximum 30 degrees

        angle_h = 0.5 + angle_h / 0.5236f;

        angle_v = 0.5 - angle_v / 0.5236f;

        // clamp

        angle_h = (angle_h < 0.0) ? 0.0 : ((angle_h > 1.0) ? 1.0 : angle_h);

        angle_v = (angle_v < 0.0) ? 0.0 : ((angle_v > 1.0) ? 1.0 : angle_v);

        if (p.renderMode == PN_Params::WarpHV) {

          (*out_p).x = angle_h;

          (*out_p).y = angle_v;

          (*out_p).z = 0.0;

          (*out_p).w = 1.0;

        } else  //  WarpHV2 case

        {

          if (!isSubWave) {

            (*out_p).y = angle_v;

            (*out_p).z = 0.0;

            (*out_p).w = 1.0;

          } else

            (*out_p).x = angle_v;

        }

      }

      // fresnel refrection mode

      else if (p.renderMode == PN_Params::Fresnel) {

        cam_vec.x *= -1.0;

        cam_vec.y *= -1.0;

        cam_vec.z *= -1.0;

        double diffuse_angle = std::acos(dot(normal, cam_vec)) * M_180_PI;

        double fresnel_ref   = getFresnel(diffuse_angle);

        double ref           = (fresnel_ref - p.base_fresnel_ref) /

                     (p.top_fresnel_ref - p.base_fresnel_ref);

        // clamp

        ref        = (ref < 0.0) ? 0.0 : ((ref > 1.0) ? 1.0 : ref);

        (*out_p).x = ref;

        (*out_p).y = ref;

        (*out_p).z = ref;

        (*out_p).w = (p.alp_rend_sw) ? ref : 1.0;

      }

    }

  }

}

//------------------------------------------------------------

void Iwa_PNPerspectiveFx::getParamUIs(TParamUIConcept *&concepts, int &length) {

  concepts = new TParamUIConcept[length = 1];

  concepts[0].m_type  = TParamUIConcept::POINT;

  concepts[0].m_label = "Eye Level";

  concepts[0].m_params.push_back(m_eyeLevel);

}

FX_PLUGIN_IDENTIFIER(Iwa_PNPerspectiveFx, "iwa_PNPerspectiveFx");