#include <gb/gb.h>
#include <string.h>

#define FADESPEED 4

extern UWORD SpritePal[];

UWORD fad[8*4];  // temp bkg palette for fade time
UWORD sfad[8*4]; // temp sprite palette for fade time

UBYTE tempe, tempf, tempg;
UWORD red, green, blue;    // fadeout temp colors
WORD  redi,greeni,bluei;    // fadein temp colors
UWORD *CurPal;

void fadeout()
{
  for (tempe = 0; tempe < 32; tempe++)
    {
      fad[tempe] = CurPal[tempe];  // put curent bkg palette to temp bkg fade palette
    }
  for (tempe = 0; tempe < 32; tempe++)
  {
    sfad[tempe] = SpritePal[tempe];// put curent sprite palette to temp sprite fade palette
  }

  for (tempg = 0; tempg < 32; tempg += FADESPEED) // do 32/FADESPEED times coz it's a bigest posible value of color
  {
    for (tempf = 0; tempf < 4; tempf++)          // do 4 times per palette
    {
      for (tempe = 0; tempe < 8; tempe++)        // do 8 times coz there is 8 paletes
      {
          /* fadeout bkg */
        red = (fad[tempe*4+tempf] & 0x1FU);
        if(red >= FADESPEED) red-=FADESPEED;
        else red = 0;
        green = ((fad[tempe*4+tempf] & 0x3E0U)/32);
        if(green >= FADESPEED) green-=FADESPEED;
        else green = 0;
        blue = (((fad[tempe*4+tempf] & 0x7C00U)/32)/32);
        if(blue >= FADESPEED) blue-=FADESPEED;
        else blue = 0;
        fad[tempe*4+tempf] = (blue*32*32)|(green*32)|red;
        set_bkg_palette_entry( tempe, tempf, fad[tempe*4+tempf]);

          /* fadeout sprites */
        red = (sfad[tempe*4+tempf] & 0x1FU);
        if(red >= FADESPEED) red-=FADESPEED;
        else red = 0;
        green = ((sfad[tempe*4+tempf] & 0x3E0U)/32);
        if(green >= FADESPEED) green-=FADESPEED;
        else green = 0;
        blue = (((sfad[tempe*4+tempf] & 0x7C00U)/32)/32);
        if(blue >= FADESPEED) blue-=FADESPEED;
        else blue = 0;
        sfad[tempe*4+tempf] = (blue*32*32)|(green*32)|red;
        set_sprite_palette_entry( tempe, tempf, sfad[tempe*4+tempf]);
      }
    }
  }
}
void fadein()
{
  for (tempg = 0; tempg < 32; tempg+=FADESPEED)
  {
    for (tempf = 0; tempf < 4; tempf++)
    {
      for (tempe = 0; tempe < 8; tempe++)
      {
          /* fadein bkg */
        redi = (((CurPal[tempe*4+tempf] & 0x1FU) - 31) + tempg);
        if (redi >= 0)
        {
          red = redi;
        }
        else red = 0;
        if (red >= (31 - FADESPEED))
        {
          red = 31;
        }
        greeni = ((((CurPal[tempe*4+tempf] & 0x3E0U)/32) - 31) + tempg);
        if (greeni >= 0)
        {
          green = greeni;
        }
        else green = 0;
        if (green >= (31 - FADESPEED)) 
        {
          green = 31;
        }
        bluei = (((((CurPal[tempe*4+tempf] & 0x7C00U)/32)/32) - 31) + tempg);
        if (bluei >= 0)
        {
          blue = bluei;
        }
        else blue = 0;
        if (blue >= (31 - FADESPEED))
        {
          blue = 31;
        }
        set_bkg_palette_entry( tempe, tempf, (blue*32*32)|(green*32)|red);

          /* fadein sprites */
        redi = (SpritePal[tempe*4+tempf] & 0x1FU) - 31 + tempg;
        if (redi >= 0) red = redi;
        else red = 0;
        if (red > 31 - FADESPEED) red = 31;
        greeni = ((SpritePal[tempe*4+tempf] & 0x3E0U)/32) - 31 + tempg;
        if (greeni >= 0) green = greeni;
        else green = 0;
        if (green > 31 - FADESPEED) green = 31;
        bluei = (((SpritePal[tempe*4+tempf] & 0x7C00U)/32)/32) - 31 + tempg;
        if (bluei >= 0) blue = bluei;
        else blue = 0;
        if (blue > 31 - FADESPEED) blue = 31; 
        set_sprite_palette_entry( tempe, tempf, (blue*32*32)|(green*32)|red);
      }
    }
  }
}