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// This file contains the declaration of the EffectParamGL and EffectGL classes.

#ifndef GPU_COMMAND_BUFFER_SERVICE_CROSS_GL_EFFECT_GL_H_
#define GPU_COMMAND_BUFFER_SERVICE_CROSS_GL_EFFECT_GL_H_

#include <vector>

#include "command_buffer/common/gapi_interface.h"
#include "command_buffer/service/resource.h"
#include "command_buffer/service/gl_utils.h"

namespace command_buffer {
namespace o3d {

class GAPIGL;
class EffectGL;

// GL version of EffectParam.
class EffectParamGL: public EffectParam {
 public:
  EffectParamGL(effect_param::DataType data_type,
                EffectGL *effect,
                unsigned int param_index);
  virtual ~EffectParamGL();

  // Sets the data into the GL effect parameter.
  bool SetData(GAPIGL *gapi, unsigned int size, const void * data);

  // Gets the description of the parameter.
  bool GetDesc(unsigned int size, void *data);

  // Resets the effect back-pointer. This is called when the effect gets
  // destroyed, to invalidate the parameter.
  void ResetEffect() { effect_ = NULL; }

  // Creates an EffectParamGL from the EffectGL, by index.
  static EffectParamGL *Create(EffectGL *effect,
                               unsigned int index);
 private:
  EffectGL *effect_;
  unsigned int low_level_param_index_;
  DISALLOW_COPY_AND_ASSIGN(EffectParamGL);
};

// GL version of Effect.
class EffectGL : public Effect {
 public:
  EffectGL(CGprogram vertex_program,
           CGprogram fragment_program);
  virtual ~EffectGL();

  // Compiles and creates an effect from source code.
  static EffectGL *Create(GAPIGL *gapi,
                          const String &effect_code,
                          const String &vertex_program_entry,
                          const String &fragment_program_entry);

  // Applies the effect states (vertex shader, pixel shader) to GL.
  bool Begin(GAPIGL *gapi);

  // Resets the effect states (vertex shader, pixel shader) to GL.
  void End(GAPIGL *gapi);

  // Gets the number of parameters in the effect.
  unsigned int GetParamCount() const;

  // Gets the number of streams in the effect.
  unsigned int GetStreamCount() const;

  // Creates an effect parameter with the specified index.
  EffectParamGL *CreateParam(unsigned int index);

  // Gets the stream data with the specified index.
  bool GetStreamDesc(unsigned int index, unsigned int size, void *data);

  // Creates an effect parameter of the specified name.
  EffectParamGL *CreateParamByName(const char *name);

 private:
  struct LowLevelParam {
    const char *name;
    CGparameter vp_param;
    CGparameter fp_param;
    int num_elements;
    std::vector<ResourceId> sampler_ids;
  };
  typedef std::vector<LowLevelParam> LowLevelParamList;
  typedef std::vector<EffectParamGL *> ParamList;
  typedef std::vector<effect_stream::Desc> StreamList;

  static CGparameter GetEitherCgParameter(
      const LowLevelParam &low_level_param) {
    return low_level_param.vp_param ?
        low_level_param.vp_param : low_level_param.fp_param;
  }

  int GetLowLevelParamIndexByName(const char *name);
  void AddLowLevelParams(CGprogram prog, CGenum name_space, bool vp);
  void AddStreams(CGprogram prog, CGenum name_space);

  // Creates the low level structures.
  void Initialize();

  // Links a param into this effect.
  void LinkParam(EffectParamGL *param);

  // Unlinks a param into this effect.
  void UnlinkParam(EffectParamGL *param);

  CGprogram vertex_program_;
  CGprogram fragment_program_;
  // List of all the Params created.
  ParamList params_;
  StreamList streams_;
  // List of all the Cg parameters present in either the vertex program or the
  // fragment program.
  LowLevelParamList low_level_params_;

  // List of the indices of the low level params that are samplers.
  std::vector<unsigned int> sampler_params_;
  bool update_samplers_;

  friend class EffectParamGL;
  DISALLOW_COPY_AND_ASSIGN(EffectGL);
};

}  // namespace o3d
}  // namespace command_buffer

#endif  // GPU_COMMAND_BUFFER_SERVICE_CROSS_GL_EFFECT_GL_H_