#include <cstdlib>
#include <cstring>

#include <algorithm>

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

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;
}

material::~material ()
{
}

void material::enable (view &ctx)
{
  pass::matmap_t &matmap = ctx.pass_data->matmap;

  pass::matmap_t::iterator i = matmap.find (this);

  if (i == matmap.end ())
    {
      string vsh_src, fsh_src;

      shader::shader_builder::start ();

      if (ctx.pass_data->l)
        ctx.pass_data->l->vsh ();

      vsh (ctx);

      // compute logarithmic depth - see the frustum matrix in view.C
      {
        using namespace shader::compile;

        temp_1f lz;
        
        // TODO: negative z is not calculated in an acceptable way
        lz = z (vout.position);
        z (vout.position) = (log2 (lz) * (2 / log2 (1e10)) - 1) * w (vout.position);
      }

      vsh_src = shader::shader_builder::stop ();

      shader::shader_builder::start ();

      if (ctx.pass_data->l)
        {
          ctx.pass_data->l->fsh ();

          fsh (ctx);
        }
      else
        shader::compile::fout.frag_color = shader::compile::float4 (1., 0., 1., 1.);

      fsh_src = shader::shader_builder::stop ();

      shader::program_object po = shader::get_program (vsh_src, fsh_src);
      matmap.insert (pass::matmap_t::value_type (this, po));

      po->enable ();
    }
  else
    i->second->enable ();

  if (ctx.pass_data->l)
    ctx.pass_data->l->enable ();
}

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

test_material::test_material ()
//: tex ("textures/osama.jpg"), texvar (tex.name)
: tex ("textures/rockwall.jpg"), texvar (tex.name)
, norm ("textures/rockwall_normal.jpg"), normvar (norm.name)
{
}

static shader::varying_3f normal;
static shader::varying_2f texcoord;

void test_material::vsh (view &ctx)
{
  using namespace shader::compile;

  std_vsh ();

  if (ctx.pass_data->l)
    {
      texcoord = xy (vin.tex_coord[0]);
      normal = normal_matrix * vin.normal;
    }
}

void test_material::fsh (view &ctx)
{
  using namespace shader::compile;

  if (ctx.pass_data->l)
    {
      temp_3f lc;
      temp_1f fac;

      temp_3f rot1, rot2, rot3;

      yxz (rot1) = (texture_2d (normvar, texcoord) * 2.F - 1.F);

      //rot1 = normal_matrix * rot1;

      rot2 = float3 (x(rot1), z(rot1), -y(rot1));
      rot3 = float3 (y(rot1), -x(rot1), z(rot1));

      normal = mat3 (rot1, rot2, rot3) * normal;

      fac = dot (normalize (normal), normalize (ctx.pass_data->l->sh_lightvec));
      fac = max (pow (max (fac, 0.0), 6), 0.3);
      xyz (fout.frag_color) = (texture_2d (texvar, texcoord) + 0.2F) * fac
                              * ctx.pass_data->l->sh_colour;
      //xyz (fout.frag_color) = lc * fac;
    }
}

void test_material::enable (view &ctx)
{
  material::enable (ctx);
  texvar->enable ();
  normvar->enable ();
}

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

test_material *testmat;