/**
 * Stone of Orthanc
 * Copyright (C) 2012-2016 Sebastien Jodogne, Medical Physics
 * Department, University Hospital of Liege, Belgium
 * Copyright (C) 2017-2019 Osimis S.A., Belgium
 *
 * This program is free software: you can redistribute it and/or
 * modify it under the terms of the GNU Affero General Public License
 * as published by the Free Software Foundation, either version 3 of
 * the License, or (at your option) any later version.
 *
 * This program 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
 * Affero General Public License for more details.
 * 
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 **/


#include "OpenGLTexture.h"

#include <Core/OrthancException.h>

namespace OrthancStone
{
  namespace OpenGL
  {
    OpenGLTexture::OpenGLTexture() :
      width_(0),
      height_(0)
    {
      // Generate a texture object
      glGenTextures(1, &texture_);
      if (texture_ == 0)
      {
        throw Orthanc::OrthancException(Orthanc::ErrorCode_InternalError,
                                        "Cannot create an OpenGL program");
      }
    }

    
    OpenGLTexture::~OpenGLTexture()
    {
      assert(texture_ != 0);
      glDeleteTextures(1, &texture_);
    }


    void OpenGLTexture::Load(const Orthanc::ImageAccessor& image,
                             bool isLinearInterpolation)
    {
      glPixelStorei(GL_UNPACK_ALIGNMENT, 1); // Disable byte-alignment restriction
    
      if (image.GetPitch() != image.GetBytesPerPixel() * image.GetWidth())
      {
        throw Orthanc::OrthancException(Orthanc::ErrorCode_NotImplemented,
                                        "Unsupported non-zero padding");
      }

      // Bind it
      glActiveTexture(GL_TEXTURE0);
      glBindTexture(GL_TEXTURE_2D, texture_);

      GLenum sourceFormat, internalFormat;

      switch (image.GetFormat())
      {
        case Orthanc::PixelFormat_Grayscale8:
          sourceFormat = GL_RED;
          internalFormat = GL_RED;
          break;

        case Orthanc::PixelFormat_RGB24:
          sourceFormat = GL_RGB;
          internalFormat = GL_RGB;
          break;

        case Orthanc::PixelFormat_RGBA32:
          sourceFormat = GL_RGBA;
          internalFormat = GL_RGBA;
          break;

        default:
          throw Orthanc::OrthancException(Orthanc::ErrorCode_NotImplemented,
                                          "No support for this format in OpenGL textures: " + 
                                          std::string(EnumerationToString(image.GetFormat())));
      }

      width_ = image.GetWidth();
      height_ = image.GetHeight();
    
      GLint interpolation = (isLinearInterpolation ? GL_LINEAR : GL_NEAREST);

      // Load the texture from the image buffer
      glTexImage2D(GL_TEXTURE_2D, 0, internalFormat, image.GetWidth(), image.GetHeight(), 
                   0, sourceFormat, GL_UNSIGNED_BYTE, image.GetBuffer());
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, interpolation);
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, interpolation);
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
    }


    void OpenGLTexture::Bind(GLint location)
    {
      glActiveTexture(GL_TEXTURE0);
      glBindTexture(GL_TEXTURE_2D, texture_);
      glUniform1i(location, 0 /* texture unit */);
    }
  }
}