#include <cstdlib>
#include <cstring>

#include <algorithm>

#include "opengl.h"
#include "material.h"
#include "view.h"
#include "util.h"

material::~material ()
{
}

void
simple_material::enable (view &ctx)
{
  glMaterialfv (GL_FRONT, GL_DIFFUSE, (GLfloat *) & diffuse);
  glMaterialfv (GL_FRONT, GL_SPECULAR, (GLfloat *) & specular);
  glMaterialfv (GL_FRONT, GL_EMISSION, (GLfloat *) & emission);
  glMaterialf (GL_FRONT, GL_SHININESS, shininess);
}

void
simple_material::disable (view &ctx)
{
}

GLuint
texture::load_texture (SDL_Surface * surface, GLfloat * tex2oord)
{
  GLuint name;
  SDL_Surface *image;
  SDL_Rect area;
  Uint32 saved_flags;
  Uint8 saved_alpha;

  /* Use the surface width and height expanded to powers of 2 */
  tex2oord[0] = 0.F;	/* Min X */
  tex2oord[1] = 0.F;	/* Min Y */
  tex2oord[2] = 1.F;	/* Max X */
  tex2oord[3] = 1.F;	/* Max Y */

  image = SDL_CreateRGBSurface (SDL_SWSURFACE, surface->w, surface->h, 32,
#if SDL_BYTEORDER == SDL_LIL_ENDIAN	/* OpenGL RGBA masks */
				0x000000FF, 0x0000FF00, 0x00FF0000, 0xFF000000
#else
				0xFF000000, 0x00FF0000, 0x0000FF00, 0x000000FF
#endif
    );

  if (image == NULL)
    return 0;

  /* Save the alpha blending attributes */
  saved_flags = surface->flags & (SDL_SRCALPHA | SDL_RLEACCELOK);
  saved_alpha = surface->format->alpha;
  if ((saved_flags & SDL_SRCALPHA) == SDL_SRCALPHA)
    SDL_SetAlpha (surface, 0, 0);

  /* Copy the surface into the GL texture image */
  area.x = 0;
  area.y = 0;
  area.w = surface->w;
  area.h = surface->h;
  SDL_BlitSurface (surface, &area, image, &area);

  /* Restore the alpha blending attributes */
  if ((saved_flags & SDL_SRCALPHA) == SDL_SRCALPHA)
    SDL_SetAlpha (surface, saved_flags, saved_alpha);

  /* Create an OpenGL texture for the image */
  glGenTextures (1, &name);
  glBindTexture (GL_TEXTURE_2D, name);
  glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
  glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
  glTexParameteri (GL_TEXTURE_2D, GL_GENERATE_MIPMAP, GL_TRUE);
  glTexImage2D (GL_TEXTURE_2D,
		0,
		GL_RGBA, surface->w, surface->h, 0, GL_RGBA, GL_UNSIGNED_BYTE, image->pixels);
  SDL_FreeSurface (image);	/* No longer needed */

  return name;
}

test_material::test_material ()
//: tex ("textures/osama.jpg"), texvar (tex.name)
: tex ("textures/rockwall.jpg"), texvar (tex.name)
, norm ("textures/rockwall_height.jpg"), normvar (norm.name)
{
  using namespace shader::compile;

  p->vsh->start ();

  temp_4f wpos;
  varying_1f camdist, zpos;
  varying_2f texcoord;
  varying_3f lightvec, normal;
  
  wpos = model_view_matrix * vin.vertex;

  temp_1f wz;
  //wz = log2 (abs (wz)) * sign (wz);

  vout.position = projection_matrix * wpos;
  texcoord = xy (vin.tex_coord[0]);
  normal = normal_matrix * vin.normal;
  lightvec = xyz (lightpos - model_view_matrix * vin.vertex);
  camdist = 1 - max (length (lightvec) / 10000., 0);

  p->vsh->stop ();

  p->fsh->start ();

  temp_1f fac;
  temp_2f disp;
  temp_1f dx, dy;
  temp_1f bumpnormal;
  temp_1f dist;

  fac = dot (normalize (normal), normalize (lightvec));
  //fac = dot (shader::compile::vec3 (normalize (fin.tex_coord[1]) + normalize (fin.tex_coord[2])) * 0.5, bumpnormal);
  //fac = dot (bumpnormal, normalize (fin.tex_coord[2]));
  fac = pow (max (fac, 0.0), 2);
  xyz (fout.frag_color) = texture_2d (texvar, texcoord) * (fac + 0.4) * camdist;

  p->fsh->stop ();
  p->link ();
}

void test_material::enable (view &ctx)
{
  p->enable ();
  lightpos->set (vec3 (0, 0, 0));
  texvar->enable ();
  normvar->enable ();
}

void test_material::disable (view &ctx)
{
  normvar->disable ();
  texvar->disable ();
  p->disable ();
}