//============================================================================
//  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/WorldAnnotatorGL.h>

#include <vtkm/Matrix.h>
#include <vtkm/rendering/BitmapFontFactory.h>
#include <vtkm/rendering/Color.h>
#include <vtkm/rendering/DecodePNG.h>
#include <vtkm/rendering/MatrixHelpers.h>
#include <vtkm/rendering/Scene.h>

#include <vtkm/rendering/internal/OpenGLHeaders.h>

namespace vtkm {
namespace rendering {

WorldAnnotatorGL::~WorldAnnotatorGL()
{  }

void WorldAnnotatorGL::AddLine(const vtkm::Vec<vtkm::Float64,3> &point0,
                               const vtkm::Vec<vtkm::Float64,3> &point1,
                               vtkm::Float32 lineWidth,
                               const vtkm::rendering::Color &color,
                               bool inFront) const
{
  if (inFront)
  {
    glDepthRange(-.0001,.9999);
  }

  glDisable(GL_LIGHTING);
  glEnable(GL_DEPTH_TEST);

  glColor3f(color.Components[0], color.Components[1], color.Components[2]);

  glLineWidth(lineWidth);

  glBegin(GL_LINES);
  glVertex3d(point0[0], point0[1], point0[2]);
  glVertex3d(point1[0], point1[1], point1[2]);
  glEnd();

  if (inFront)
  {
    glDepthRange(0,1);
  }
}

void WorldAnnotatorGL::AddText(const vtkm::Vec<vtkm::Float32,3> &origin,
                               const vtkm::Vec<vtkm::Float32,3> &right,
                               const vtkm::Vec<vtkm::Float32,3> &up,
                               vtkm::Float32 scale,
                               const vtkm::Vec<vtkm::Float32,2> &anchor,
                               const vtkm::rendering::Color &color,
                               const std::string &text) const
{

  vtkm::Vec<vtkm::Float32,3> n = vtkm::Cross(right,up);
  vtkm::Normalize(n);

  vtkm::Matrix<vtkm::Float32,4,4> m;
  m = MatrixHelpers::WorldMatrix(origin, right, up, n);

  vtkm::Float32 ogl[16];
  MatrixHelpers::CreateOGLMatrix(m, ogl);
  glPushMatrix();
  glMultMatrixf(ogl);
  glColor3f(color.Components[0], color.Components[1], color.Components[2]);
  this->RenderText(scale, anchor[0], anchor[1], text);
  glPopMatrix();
}

void WorldAnnotatorGL::RenderText(vtkm::Float32 scale,
                                  vtkm::Float32 anchorx, vtkm::Float32 anchory,
                                  std::string text) const
{
  if (!this->FontTexture.Valid())
  {
    // When we load a font, we save a reference to it for the next time we
    // use it. Although technically we are changing the state, the logical
    // state does not change, so we go ahead and do it in this const
    // function.
    vtkm::rendering::WorldAnnotatorGL *self =
        const_cast<vtkm::rendering::WorldAnnotatorGL *>(this);
    self->Font = BitmapFontFactory::CreateLiberation2Sans();
    const std::vector<unsigned char> &rawpngdata =
        this->Font.GetRawImageData();

    std::vector<unsigned char> rgba;
    unsigned long width, height;
    int error = vtkm::rendering::DecodePNG(rgba, width, height,
                                           &rawpngdata[0], rawpngdata.size());
    if (error != 0)
    {
      return;
    }

    self->FontTexture.CreateAlphaFromRGBA(int(width),int(height),rgba);
  }


  this->FontTexture.Enable();

  glDepthMask(GL_FALSE);
  glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
  glEnable(GL_BLEND);
  glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
  glDisable(GL_LIGHTING);
  //glTexEnvf(GL_TEXTURE_FILTER_CONTROL, GL_TEXTURE_LOD_BIAS, -.5);

  glBegin(GL_QUADS);

  vtkm::Float32 textwidth = this->Font.GetTextWidth(text);

  vtkm::Float32 fx = -(.5f + .5f*anchorx) * textwidth;
  vtkm::Float32 fy = -(.5f + .5f*anchory);
  vtkm::Float32 fz = 0;
  for (unsigned int i=0; i<text.length(); ++i)
  {
    char c = text[i];
    char nextchar = (i < text.length()-1) ? text[i+1] : 0;

    vtkm::Float32 vl,vr,vt,vb;
    vtkm::Float32 tl,tr,tt,tb;
    this->Font.GetCharPolygon(c, fx, fy,
                        vl, vr, vt, vb,
                        tl, tr, tt, tb, nextchar);

    glTexCoord2f(tl, 1.f-tt);
    glVertex3f(scale*vl, scale*vt, fz);

    glTexCoord2f(tl, 1.f-tb);
    glVertex3f(scale*vl, scale*vb, fz);

    glTexCoord2f(tr, 1.f-tb);
    glVertex3f(scale*vr, scale*vb, fz);

    glTexCoord2f(tr, 1.f-tt);
    glVertex3f(scale*vr, scale*vt, fz);
  }

  glEnd();

  this->FontTexture.Disable();

  //glTexEnvf(GL_TEXTURE_FILTER_CONTROL, GL_TEXTURE_LOD_BIAS, 0);
  glDepthMask(GL_TRUE);
  glDisable(GL_ALPHA_TEST);
}

}
} // namespace vtkm::rendering
