#ifndef MATERIAL_H
#define MATERIAL_H

#include <vector>
#include <string>
#include <sstream>

using namespace std;

#include "opengl.h"
#include "util.h"
#include "shader.h"

inline void std_vsh ()
{
  using namespace shader::compile;

  vout.position = ftransform ();
}

inline void std_vsh (const shader::gluvar &vertex)
{
  using namespace shader::compile;

  vout.position = model_view_projection_matrix * vertex;
}

struct material
{
  // the vertex shader fragment. it should check ctx.pass_data->light and
  // only generate varying data when light is non-null. it should also use
  // std_vsh () whenever possible.

  virtual void vsh (view &ctx) = 0;

  // the fragment shader fragment :). it should check ctx.pass_data->light
  // and, if null, best do nothing. if non-null, it should call
  // light->value to get the per-pixel light colour and apply it to the
  // surface as neccessary.

  virtual void fsh (view &ctx) = 0;

  virtual void enable (view &ctx);
  virtual void disable (view &ctx);

  virtual ~material ();
};

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

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

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

  enum {
    DISABLE_MIPMAP = 1,
    CLAMP          = 2,
  };

  texture (const char *f, int flags = 0)
  {
    image = IMG_Load (f);

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

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

/////////////////////////////////////////////////////////////////////////////

struct test_material : material
{
  texture tex, norm;
  shader::sampler_2d texvar, normvar;

  void vsh (view &ctx);
  void fsh (view &ctx);

  void enable (view &ctx);
  void disable (view &ctx);

  test_material ();
};

struct skybox_material : material
{
  shader::sampler_2d tex;

  void vsh (view &ctx);
  void fsh (view &ctx);

  void enable (view &ctx);
  void disable (view &ctx);

  skybox_material ();
};

struct mat_timed : material
{
  shader::uniform_1f time;
  
  void enable  (view &ctx);
  void disable (view &ctx);

  void vsh (view &ctx);
  void fsh (view &ctx);

protected:
  shader::varying_3f f_normal;
  shader::uniform_3f sh_colour;
};

struct mat_gouraud_shaded : material
{
//  texture tex, norm;
//  shader::sampler_2d texvar, normvar;
  colour c;

  void vsh (view &ctx);
  void fsh (view &ctx);

  void enable (view &ctx);
  void disable (view &ctx);

  mat_gouraud_shaded (const colour &c) : c(c) { }

protected:
  shader::uniform_3f sh_colour;
  shader::varying_3f f_normal;
};

struct mat_debug : material {
  void vsh (view &ctx);
  void fsh (view &ctx);

  void enable (view &ctx);
  void disable (view &ctx);

  mat_debug () { }
};

extern test_material *testmat;
extern mat_gouraud_shaded *testmat2;
extern mat_timed *testmat3;
extern mat_debug *debugmat;

#endif