//============================================================================
//  Copyright (c) Kitware, Inc.
//  All rights reserved.
//  See LICENSE.txt for details.
//  This software is distributed WITHOUT ANY WARRANTY; without even
//  the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
//  PURPOSE.  See the above copyright notice for more information.
//
//  Copyright 2016 Sandia Corporation.
//  Copyright 2016 UT-Battelle, LLC.
//  Copyright 2016 Los Alamos National Security.
//
//  Under the terms of Contract DE-AC04-94AL85000 with Sandia Corporation,
//  the U.S. Government retains certain rights in this software.
//
//  Under the terms of Contract DE-AC52-06NA25396 with Los Alamos National
//  Laboratory (LANL), the U.S. Government retains certain rights in
//  this software.
//============================================================================

#include <vtkm/rendering/TextAnnotationBillboard.h>

#include <vtkm/Matrix.h>

namespace vtkm {
namespace rendering {

TextAnnotationBillboard::TextAnnotationBillboard(
    const std::string &text,
    const vtkm::rendering::Color &color,
    vtkm::Float32 scalar,
    const vtkm::Vec<vtkm::Float32,3> &position,
    vtkm::Float32 angleDegrees)
  : TextAnnotation(text, color, scalar),
    Position(position),
    Angle(angleDegrees)
{  }

TextAnnotationBillboard::~TextAnnotationBillboard()
{  }

void TextAnnotationBillboard::SetPosition(
    const vtkm::Vec<vtkm::Float32,3> &position)
{
  this->Position = position;
}

void TextAnnotationBillboard::SetPosition(
    vtkm::Float32 xpos, vtkm::Float32 ypos, vtkm::Float32 zpos)
{
  this->SetPosition(vtkm::make_Vec(xpos, ypos, zpos));
}

void TextAnnotationBillboard::Render(
    const vtkm::rendering::Camera &camera,
    const vtkm::rendering::WorldAnnotator &worldAnnotator,
    vtkm::rendering::Canvas &canvas) const
{
  using MatrixType = vtkm::Matrix<vtkm::Float32,4,4>;
  using VectorType = vtkm::Vec<vtkm::Float32,3>;

  MatrixType viewMatrix = camera.CreateViewMatrix();
  MatrixType projectionMatrix
      = camera.CreateProjectionMatrix(canvas.GetWidth(), canvas.GetHeight());

  VectorType screenPos =
      vtkm::Transform3DPointPerspective(
        vtkm::MatrixMultiply(projectionMatrix,viewMatrix),
        this->Position);

  canvas.SetViewToScreenSpace(camera,true);


  MatrixType translateMatrix =
      vtkm::Transform3DTranslate(screenPos[0], screenPos[1], -screenPos[2]);

  vtkm::Float32 windowAspect =
    vtkm::Float32(canvas.GetWidth()) / vtkm::Float32(canvas.GetHeight());

  MatrixType scaleMatrix = vtkm::Transform3DScale(1.f/windowAspect, 1.f, 1.f);

  MatrixType viewportMatrix;
  vtkm::MatrixIdentity(viewportMatrix);
  //if view type == 2D?
  {
    vtkm::Float32 vl, vr, vb, vt;
    camera.GetRealViewport(canvas.GetWidth(),canvas.GetHeight(),vl,vr,vb,vt);
    vtkm::Float32 xs = (vr-vl);
    vtkm::Float32 ys = (vt-vb);
    viewportMatrix = vtkm::Transform3DScale(2.f/xs, 2.f/ys, 1.f);
  }

  MatrixType rotateMatrix =
      vtkm::Transform3DRotateZ(this->Angle * 3.14159265f / 180.f);

  vtkm::Matrix<vtkm::Float32, 4, 4> fullTransformMatrix =
    vtkm::MatrixMultiply(translateMatrix,
    vtkm::MatrixMultiply(scaleMatrix,
    vtkm::MatrixMultiply(viewportMatrix,
                         rotateMatrix)));

  VectorType origin =
      vtkm::Transform3DPointPerspective(fullTransformMatrix, VectorType(0,0,0));
  VectorType right =
      vtkm::Transform3DVector(fullTransformMatrix, VectorType(1,0,0));
  VectorType up =
      vtkm::Transform3DVector(fullTransformMatrix, VectorType(0,1,0));

  worldAnnotator.AddText(origin,
                         right,
                         up,
                         this->Scale,
                         this->Anchor,
                         this->TextColor,
                         this->Text);

  canvas.SetViewToWorldSpace(camera,true);
}

}
} // vtkm::rendering