Hydlide (NES) map ripper

a.c

/***

hydlide (nes) map ripper

coded by karmic, jan 27 2022

requires libpng (compile with "-lpng")

rom must be in the working directory and called "Hydlide (U) [!].nes"

***/


#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <stdint.h>
#include <setjmp.h>

#include <png.h>


/***

map writing subroutine is at $d4bb
map is written to a buffer row by row
screen pointers are at $ec00-$ec45

attribute writing subroutine is at $dc8d
attributes are written row by row, in steps of two columns
tile->attribute table is at $dfc4

the player starts on screen 0, the first 25 screens are the game map, arranged row by row, then the underground parts

***/

uint16_t inline get16(uint8_t *p) { return p[0] | (p[1]<<8); }


#define SCREENSIZE (0x16)

uint8_t screenbuf[SCREENSIZE][SCREENSIZE];


png_color inline getcolor(uint32_t c)
{
  png_color co;
  co.red = (c>>16)&0xff;
  co.green = (c>>8)&0xff;
  co.blue = (c>>0)&0xff;
  return co;
}

const uint32_t palette[] = { 0xFF666666, 0xFF002A88, 0xFF1412A7, 0xFF3B00A4, 0xFF5C007E, 0xFF6E0040, 0xFF6C0600, 0xFF561D00, 0xFF333500, 0xFF0B4800, 0xFF005200, 0xFF004F08, 0xFF00404D, 0xFF000000, 0xFF000000, 0xFF000000, 0xFFADADAD, 0xFF155FD9, 0xFF4240FF, 0xFF7527FE, 0xFFA01ACC, 0xFFB71E7B, 0xFFB53120, 0xFF994E00, 0xFF6B6D00, 0xFF388700, 0xFF0C9300, 0xFF008F32, 0xFF007C8D, 0xFF000000, 0xFF000000, 0xFF000000, 0xFFFFFEFF, 0xFF64B0FF, 0xFF9290FF, 0xFFC676FF, 0xFFF36AFF, 0xFFFE6ECC, 0xFFFE8170, 0xFFEA9E22, 0xFFBCBE00, 0xFF88D800, 0xFF5CE430, 0xFF45E082, 0xFF48CDDE, 0xFF4F4F4F, 0xFF000000, 0xFF000000, 0xFFFFFEFF, 0xFFC0DFFF, 0xFFD3D2FF, 0xFFE8C8FF, 0xFFFBC2FF, 0xFFFEC4EA, 0xFFFECCC5, 0xFFF7D8A5, 0xFFE4E594, 0xFFCFEF96, 0xFFBDF4AB, 0xFFB3F3CC, 0xFFB5EBF2, 0xFFB8B8B8, 0xFF000000, 0xFF000000 };

#define BGCOLOR (0x0f)
const uint8_t gamepal[] = {0x2a,0x18,0x1a, 0x14,0x28,0x30, 0x10,0x00,0x12, 0x00,0x10,0x2a};

#define PNGPALSIZE (4*3 + 1)
png_color pngpal[PNGPALSIZE];


#define BMPSIZE (SCREENSIZE*8)
png_byte bmp[BMPSIZE][BMPSIZE];
png_bytep bmprows[BMPSIZE];


uint8_t prg[0x8000];
uint8_t chr[0x2000];



int main()
{
  FILE *f = fopen("Hydlide (U) [!].nes","rb");
  if (!f)
  {
    perror("rom open error");
    return EXIT_FAILURE;
  }
  fseek(f,0x10,SEEK_SET);
  fread(prg,1,sizeof(prg),f);
  fread(chr,1,sizeof(chr),f);
  fclose(f);
  
  pngpal[0] = getcolor(palette[BGCOLOR]);
  for (int i = 0; i < sizeof(gamepal); i++)
    pngpal[i+1] = getcolor(palette[gamepal[i]]);
  
  for (int i = 0; i < BMPSIZE; i++)
    bmprows[i] = bmp[i];
  
  
  for (int screen = 0; screen < (0x46/2); screen++)
  {
    /* screen */
    memset(screenbuf,0x40,sizeof(screenbuf));
    
    uint8_t *p = prg+get16(prg+0x6c00+(screen*2))-0x8000;
    uint8_t *sp = (uint8_t*)screenbuf;
    
    unsigned repcnt = 0;
    unsigned tile;
    
    while (sp < (uint8_t*)screenbuf+sizeof(screenbuf))
    {
      if (!repcnt)
      {
        unsigned b = *p++;
        
        repcnt = b & 0x0f;
        if (!repcnt) repcnt = 0x10;
        
        tile = b >> 4;
      }
      
      if (tile < 9)
        *sp = tile;
      else if (tile < 0x0d)
      {
        unsigned t = (tile-9)*4 + 9;
        
        sp[0] = t;
        sp[1] = t+1;
        sp[0 + SCREENSIZE] = t+2;
        sp[1 + SCREENSIZE] = t+3;
      }
      else if (tile < 0x0e)
      {
        sp[0] = 0x19;
        sp[1] = 0x1a;
        sp[2] = 0x1b;
        sp[3] = 0x1c;
        
        sp[SCREENSIZE + 0] = 0x1d;
        sp[SCREENSIZE + 1] = 0x1e;
        sp[SCREENSIZE + 2] = 0x1f;
        sp[SCREENSIZE + 3] = 0x20;
        
        sp[SCREENSIZE*2 + 0] = 0x21;
        sp[SCREENSIZE*2 + 1] = 0x22;
        sp[SCREENSIZE*2 + 2] = 0x23;
        sp[SCREENSIZE*2 + 3] = 0x24;
        
        sp[SCREENSIZE*3 + 0] = 0x25;
        sp[SCREENSIZE*3 + 1] = 0x26;
        sp[SCREENSIZE*3 + 2] = 0x27;
        sp[SCREENSIZE*3 + 3] = 0x28;
      }
      
      
      --repcnt;
      
      sp++;
    }
    
    
    
    /* image */
    memset(bmp,0,sizeof(bmp));
    for (int ytile = 0; ytile < SCREENSIZE; ytile++)
    {
      for (int xtile = 0; xtile < SCREENSIZE; xtile++)
      {
        unsigned t = screenbuf[ytile][xtile];
        unsigned attr = prg[0x5fc4 + t];
        
        uint8_t *td = &chr[0x1000+(t*0x10)];
        
        for (int yf = 0; yf < 8; yf++)
        {
          for (int xf = 0; xf < 8; xf++)
          {
            unsigned x = (xtile*8)+xf;
            unsigned y = (ytile*8)+yf;
            
            unsigned tm = (0x80)>>xf;
            unsigned tc = (td[yf] & tm ? 1 : 0) | (td[yf+8] & tm ? 2 : 0);
            
            unsigned c = !tc ? 0 : (attr*3)+(tc-1)+1;
            
            bmp[y][x] = c;
          }
        }
      }
    }
    
    
    /* output png */
    char fnam[16];
    sprintf(fnam, "%02i.png",screen);
    
    void pngerr(png_structp p, const char *e)
    {
      fprintf(stderr,"%s libpng error: %s\n",fnam,e);
    }
    void pngwarn(png_structp p, const char *e)
    {
      fprintf(stderr,"%s libpng warning: %s\n",fnam,e);
    }
    
    FILE *f = fopen(fnam,"wb");
    if (!f)
    {
      fprintf(stderr, "%s open error: %s\n", fnam,strerror(errno));
      continue;
    }
    
    png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING,NULL,pngerr,pngwarn);
    if (!png_ptr)
    {
      fprintf(stderr,"%s png init error\n", fnam);
      fclose(f);
      continue;
    }
    png_infop info_ptr = png_create_info_struct(png_ptr);
    if (!info_ptr)
    {
      fprintf(stderr,"%s png info init error\n", fnam);
      png_destroy_write_struct(&png_ptr,NULL);
      fclose(f);
      continue;
    }
    
    if (setjmp(png_jmpbuf(png_ptr)))
    {
      
    }
    else
    {
      png_init_io(png_ptr,f);
      
      png_set_IHDR(png_ptr,info_ptr, BMPSIZE,BMPSIZE, 4,PNG_COLOR_TYPE_PALETTE,
                    PNG_INTERLACE_NONE,PNG_COMPRESSION_TYPE_DEFAULT,PNG_FILTER_TYPE_DEFAULT);
      png_set_PLTE(png_ptr,info_ptr,pngpal,PNGPALSIZE);
      
      png_write_info(png_ptr,info_ptr);
      png_set_packing(png_ptr);
      png_write_image(png_ptr,bmprows);
      png_write_end(png_ptr,info_ptr);
      
      fprintf(stderr, "exported %s\n",fnam);
    }
    
    png_destroy_write_struct(&png_ptr,&info_ptr);
    fclose(f);
  }
  
}