#pragma once
 
#ifndef SHADINGCONTEXT_H
#define SHADINGCONTEXT_H
 
#include <memory>
 
// Glew include
#include <GL/glew.h>
 
// TnzCore includes
#include "traster.h"
 
// Qt includes
#include <QDateTime>
#include <QGLFramebufferObjectFormat>
 
#undef DVAPI
#undef DVVAR
#ifdef TNZSTDFX_EXPORTS
#define DVAPI DV_EXPORT_API
#define DVVAR DV_EXPORT_VAR
#else
#define DVAPI DV_IMPORT_API
#define DVVAR DV_IMPORT_VAR
#endif
 
//=========================================================
 
//    Forward declarations
 
class QObject;
class QGLShaderProgram;
class QDateTime;
 
//=========================================================
 
class DVAPI ShadingContext {
public:
  enum Support { OK, NO_PIXEL_BUFFER, NO_SHADERS };
 
public:
  ShadingContext();
  ~ShadingContext();
 
  //! Returns the status of OpenGL shading support.
  static Support support();
 
  bool isValid() const;
 
  void makeCurrent();
  void doneCurrent();
 
  /*!
Resizes the output buffer to the specified size. Requires that
the contex is made current before invocation. In case lx or ly are 0,
the context's output buffer is destroyed.
*/
  void resize(int lx, int ly, const QGLFramebufferObjectFormat &fmt =
                                  QGLFramebufferObjectFormat());
 
  QGLFramebufferObjectFormat format() const;
  TDimension size() const;
 
  //! Surrenders ownership of the supplied shader program to the shading
  //! context.
  void addShaderProgram(const QString &shaderName, QGLShaderProgram *program);
  void addShaderProgram(const QString &shaderName, QGLShaderProgram *program,
                        const QDateTime &lastModified);
  bool removeShaderProgram(const QString &shaderName);
 
  QGLShaderProgram *shaderProgram(const QString &shaderName) const;
  QDateTime lastModified(const QString &shaderName) const;
 
  std::pair<QGLShaderProgram *, QDateTime> shaderData(
      const QString &shaderName) const;
 
  GLuint loadTexture(const TRasterP &src, GLuint texUnit);  //!< Loads a texture
                                                            //! and binds it to
  //! the specified
  //! texture unit.
  //!  \return  The OpenGL texture id of the loaded texture.      \param src
  //!  Loaded texture.  \param texUnit  Unit the texture will be bound to.
  void unloadTexture(GLuint texId);  //!< Releases the specified texture id.
 
  //! Renders the active shader program to the specified raster.
  void draw(const TRasterP &dst);
 
  //! Performs transform feedback with the specified varying variables
  void transformFeedback(int varyingsCount, const GLsizeiptr *varyingSizes,
                         GLvoid **bufs);
 
private:
  struct Imp;
  std::unique_ptr<Imp> m_imp;
 
  // Not copyable
  ShadingContext(const ShadingContext &);
  ShadingContext &operator=(const ShadingContext &);
};
 
#endif  // SHADINGCONTEXT_H