/***

  Olive - Non-Linear Video Editor
  Copyright (C) 2019 Olive Team

  This program is free software: you can redistribute it and/or modify
  it under the terms of the GNU 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 General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program.  If not, see <http://www.gnu.org/licenses/>.

***/

#include "waveform.h"

#include "node/node.h"
#include "render/backend/opengl/openglrenderfunctions.h"

OLIVE_NAMESPACE_ENTER

WaveformScope::WaveformScope(QWidget* parent) :
  ManagedDisplayWidget(parent),
  buffer_(nullptr)
{
  EnableDefaultContextMenu();
}

WaveformScope::~WaveformScope()
{
  CleanUp();

  if (context()) {
    disconnect(context(), &QOpenGLContext::aboutToBeDestroyed, this, &WaveformScope::CleanUp);
  }
}

void WaveformScope::SetBuffer(Frame *frame)
{
  buffer_ = frame;

  UploadTextureFromBuffer();
}

void WaveformScope::showEvent(QShowEvent* e)
{
  ManagedDisplayWidget::showEvent(e);

  UploadTextureFromBuffer();
}

void WaveformScope::initializeGL()
{
  ManagedDisplayWidget::initializeGL();

  makeCurrent();
  pipeline_ = OpenGLShader::Create();
  pipeline_->create();
  pipeline_->addShaderFromSourceCode(QOpenGLShader::Vertex, OpenGLShader::CodeDefaultVertex());
  pipeline_->addShaderFromSourceCode(QOpenGLShader::Fragment, Node::ReadFileAsString(":/shaders/rgbwaveform.frag"));
  pipeline_->link();
  doneCurrent();

  connect(context(), &QOpenGLContext::aboutToBeDestroyed, this, &WaveformScope::CleanUp, Qt::DirectConnection);

  UploadTextureFromBuffer();
}

void WaveformScope::paintGL()
{
  context()->functions()->glClearColor(0, 0, 0, 0);
  context()->functions()->glClear(GL_COLOR_BUFFER_BIT);

  if (!pipeline_ || !texture_.IsCreated()) {
    return;
  }

  pipeline_->bind();
  pipeline_->setUniformValue("ove_resolution", texture_.width(), texture_.height());
  pipeline_->setUniformValue("ove_viewport", width(), height());

  // The general size of a pixel
  pipeline_->setUniformValue("threshold", 2.0f / static_cast<float>(height()));

  pipeline_->release();

  texture_.Bind();

  OpenGLRenderFunctions::Blit(pipeline_);

  texture_.Release();
}

void WaveformScope::UploadTextureFromBuffer()
{
  if (!buffer_ || !isVisible()) {
    return;
  }

  makeCurrent();

  if (!texture_.IsCreated()
      || texture_.width() != buffer_->width()
      || texture_.height() != buffer_->height()
      || texture_.format() != buffer_->format()) {
    texture_.Destroy();
    texture_.Create(context(), buffer_);
  } else {
    texture_.Upload(buffer_);
  }

  doneCurrent();

  update();
}

void WaveformScope::CleanUp()
{
  makeCurrent();

  pipeline_ = nullptr;
  texture_.Destroy();

  doneCurrent();
}

OLIVE_NAMESPACE_EXIT