#ifndef MATERIAL_H
#define MATERIAL_H

#include "util.h"


struct texture_execption
{ 
  texture_execption (string s) : msg(s) { }
  string msg; 
};

inline int power_of_two (int input)
{
  int value = 1;

  while (value < input)
    {
      value <<= 1;
    }
  return value;
}



struct material
{
  virtual void begin () = 0;
  virtual void end () = 0;
  virtual ~material ();
};

struct simple_material : material
{
  colour diffuse, specular, emission;
  GLfloat shininess;

  void begin ();
  void end ();

  simple_material () 
  : diffuse(1, 0, 1, 1)
  , specular(1, 0, 1, 1)
  , emission(1, 0, 1, 1)
  , shininess(1.)
  {
  }
};

struct texture
{
  SDL_Surface *image;
  GLuint texture_pxls;
  GLfloat texcoord[4];

  GLuint load_texture (SDL_Surface *surface, GLfloat *texcoord);

  texture(const char *f)
  {
    image = IMG_Load (f);

    if (!image) 
      throw (texture_execption ("Couldn't load " + (string) f + ": " + (string) IMG_GetError ()));

    texture_pxls = load_texture (image, (GLfloat*)&texcoord);
    if (texture_pxls == 0) 
      throw (texture_execption ("Couldn't make GL Texture, failed to create new RGB SWSurface"));
  }
};

extern CGcontext cgc;

struct shader 
{
   CGprogram vsh, fsh;
   CGparameter lightpos;
   // mv, mvp
   CGprofile vsh_profile, fsh_profile;
   CGparameter g_Texture; // the texture parameter

   void check_cg_error (void)
   {
     CGerror err = cgGetError ();

     if (err != CG_NO_ERROR)
       {
         printf("CG error: %s\n", cgGetErrorString (err));
         exit(1);
       }
   }
   shader (const char *vshp, const char *fshp)
   {
     vsh_profile = CG_PROFILE_ARBVP1;
     //if (cgGLIsProfileSupported (CG_PROFILE_VP30)) vsh_profile = CG_PROFILE_VP30;
     //if (cgGLIsProfileSupported (CG_PROFILE_VP40)) vsh_profile = CG_PROFILE_VP40;
     fsh_profile = CG_PROFILE_ARBFP1;
     //if (cgGLIsProfileSupported (CG_PROFILE_FP30)) fsh_profile = CG_PROFILE_FP30;
     //if (cgGLIsProfileSupported (CG_PROFILE_FP40)) fsh_profile = CG_PROFILE_FP40;

     vsh = cgCreateProgramFromFile (cgc, CG_SOURCE, vshp, vsh_profile, 0, 0);
     check_cg_error ();
     cgGLLoadProgram (vsh);
     check_cg_error ();

     fsh = cgCreateProgramFromFile (cgc, CG_SOURCE, fshp, fsh_profile, 0, 0);
     check_cg_error ();
     cgGLLoadProgram (fsh);
     check_cg_error ();

     cgGLBindProgram (vsh);
     cgGLBindProgram (fsh);

    // mv = cgGetNamedParameter (vsh, "WorldProj");
    // mvp = cgGetNamedParameter (vsh, "WorldViewProj");
     //lightpos = cgGetNamedParameter (vsh, "LightPos");
     //cgGLSetParameter4f (lightpos, 10, 10, 0, 1); //camera.p.x, camera.p.y, camera.p.z, 1);

     check_cg_error ();
   }
};

struct osama_material : material, texture, shader {
  osama_material () 
  : shader ("vsh.cg", "fsh.cg"), texture ("textures/osama.jpg") 
  {
     g_Texture = cgGetNamedParameter(fsh, "Texture"); // the texture cg-warper ;)
     cgGLSetTextureParameter(g_Texture, texture_pxls); // Bind the texture number 999 to g_Texture
  }

  void begin ();
  void end ();

};

void init_shaders ();
#endif