Styjun

I am trying to import Anand.BMP file in the graphics window of TCPP,

for this its source code is as follows

(NOTE: I have not mentioned the header files in the source code):

struct A

 char type[2];
 unsigned long size;
 unsigned short int reserved1,reserved2;
 unsigned long offset;
 unsigned long width,height;
 unsigned short int planes;
 unsigned short int bits;
 unsigned long compression;
 unsigned long imagesize;
 unsigned long xresolution,yresolution;
 unsigned long ncolors;
 unsigned long importantcolors;
HEADER;
huge DetectSvga()

 return 2;

void show()

 fstream File;
 File.open("C:\TURBOC3\BIN\Anand.BMP",ios::in
void main()

 clrscr();
 int gd=DETECT,gm,a;
 initgraph(&gd,&gm,"C:\TURBOC3\BGI");
 installuserdriver("svga256",&DetectSvga);
 show();
 getch();
 closegraph();

Now, i am not getting the BMP file in the graphics window,

i.e,

Graphics Window is not displaying Anand.bmp properly; Output is displayed like this

so how to fix it?
Here I am attaching my Anand.BMP file for convenience.

I think palette is not properly displayed through PaletteData pointer,

i.e, error is in this block of codes:

for(i=0;i<256;i++)
 
 File.read(ColorBytes,4);
 PaletteData[(int)(i*3+2)]=ColorBytes[0]>>2;
 PaletteData[(int)(i*3+0)]=ColorBytes[2]>>2;
 

As per suggestions I have modified the above codes as follows:
[EDIT] :

typedef unsigned long DWORD;
typedef unsigned int WORD;
typedef unsigned short BYTE;

//---------------------------------------------------------------------------
class BMP

 public:
 BYTE *data;
 DWORD size;
 #pragma pack(push,1)
 struct _hdr
 
 char ID[2];
 DWORD size;
 WORD reserved1[2]; // ?
 DWORD offset;
 DWORD reserved2; // ?
 DWORD width,height;
 WORD planes;
 WORD bits;
 DWORD compression;
 DWORD imagesize;
 DWORD xresolution,yresolution;
 DWORD ncolors;
 DWORD importantcolors;
 ;
 #pragma pack(pop)
 BMP() data=NULL; free(); 

 ~BMP() free(); 

 void free() if (data) delete[] data; data=NULL; size=0; 
 void load(char* filename)
 
 FILE *hnd;
 free();
 if ((hnd=fopen(filename, "rb")) == NULL) return; // open file for read binary (not sure with the "b" check in build help)
 size=fseek(hnd,0,2);
 fseek(hnd,0,0);
 BYTE data[256];
 if (data==NULL) // not enough memory or empty file
 
 size=0;
 fclose(hnd); 
 return;
 
 fread(data,256,1,hnd); // read 256 of 1 BYTES into data array
 fclose(hnd); // close file
 
 void draw(int x0,int y0)
 
 _hdr *hdr=(_hdr*)data;
 int x,y,xs,ys,skip;
 DWORD pal[256],c; // palete to convert 8bpp -> 32bit VCL color
 BYTE *p;
 if (size<2) return;
 if (hdr->ID[0]!='B') return; // check magic number
 if (hdr->ID[1]!='M') return;
 if (hdr->planes!=1) return; // check format
 if (hdr->bits!=8) return;
 if (hdr->compression!=0) return;
 // palette
 p=data+hdr->offset-(3*256);
 p=data+sizeof(_hdr);
 for (x=0;x<256;x++)
 =(*p)<<16; p++; // R
 p++; // A
 pal[x]=c;
 
 // image
 xs=hdr->width;
 ys=hdr->height;
 p=data+hdr->offset;
 skip=(((hdr->bits*hdr->width)+31)>>5)<<2; // compute scanline align
 skip-=hdr->width;
 for (y=0;y<ys;y++)
 
 for (x=0;x<xs;x++,p++)
 
 putpixel(x0+x,y0+ys-y-1,*p);
 
 p+=skip; // handle align
 
 y++;
 
;
//---------------------------------------------------------------------------

 huge DetectSvga()

 return 2;


void main()

 clrscr();
 int gd=DETECT,gm,a;
 initgraph(&gd,&gm,"C:\TURBOC3\BGI");
 installuserdriver("svga256",&DetectSvga);
 BMP bmp;
 bmp.load("C:\TURBOC3\BIN\Anand.BMP");
 bmp.draw(0,0);
 getch();
 closegraph();

Now,the above code is giving no errors but 2 warnings !!

WARNING :
1: for(x=0;x<256;x++) : "Functions containing for are not expanded inline"
2 : } , i.e, at the end of void load() function : "Functions containing some if statements are not expanded inline"

As a result image is not displaying in the output window
Output is displayed like this

I think y++; should be inside for (y=0;y<ys;y++)... loop

So,please analyse the edited code...

Your decoding BMP code has a lot of problems... As I mentioned in my comments BMP is a mess with too many variations of format where you get lost very quickly so you need to have BMP format matching your decoding routine...

Yes you change BMP to 8bpp but still its format is different to yours slightly ...

Ok let use this image of yours (why to heck imgur is not supporting this???).

After a while of (de)coding I come up with this C++/VCL code that decodes your bmp properly:

//---------------------------------------------------------------------------
class BMP
 
public:
 BYTE *data;
 DWORD size;
 #pragma pack(push,1)
 struct _hdr
 
 char ID[2];
 DWORD size;
 WORD reserved1[2]; // ?
 DWORD offset;
 DWORD reserved2; // ?
 DWORD width,height;
 WORD planes;
 WORD bits;
 DWORD compression;
 DWORD imagesize;
 DWORD xresolution,yresolution;
 DWORD ncolors;
 DWORD importantcolors;
 ;
 #pragma pack(pop)
 BMP() data=NULL; free(); 
 ~BMP() free(); 
 void free() if (data) delete[] data; data=NULL; size=0; 

 void load(AnsiString filename) // load BMP into memory
 
 int hnd;
 free();
 hnd=FileOpen(filename,fmOpenRead); // open file
 if (hnd<0) return;
 size=FileSeek(hnd,0,2); // seek to end of file to obtain filesize
 FileSeek(hnd,0,0); // seek to start of file
 data=new BYTE[size]; // allocate memory space for the BMP
 if (data==NULL) // not enough memory or empty file
 
 size=0;
 FileClose(hnd);
 return;
 
 FileRead(hnd,data,size); // load the data
 FileClose(hnd);
 
 void draw(Graphics::TBitmap *bmp,int x0,int y0) // decode/render bitmap onto VCL bitmap
 
 _hdr *hdr=(_hdr*)data;
 int x,y,xs,ys,skip;
 DWORD pal[256],c; // palete to convert 8bpp -> 32bit VCL color
 BYTE *p;
 if (size<2) return;
 if (hdr->ID[0]!='B') return; // check magic number
 if (hdr->ID[1]!='M') return;
 if (hdr->planes!=1) return; // check format
 if (hdr->bits!=8) return;
 if (hdr->compression!=0) return;
 // palette
 p=data+hdr->offset-(3*256);
 p=data+sizeof(_hdr);
 for (x=0;x<256;x++)
 =(*p)<<16; p++; // R
 p++; // A
 pal[x]=c;
 
 // image
 xs=hdr->width;
 ys=hdr->height;
 p=data+hdr->offset;
 skip=(((hdr->bits*hdr->width)+31)>>5)<<2; // compute scanline align
 skip-=hdr->width;
 for (y=0;y<ys;y++)
 
 DWORD *q=(DWORD*)bmp->ScanLine[y0+ys-y-1]; // target VCL bitmap scanline pointer
 for (x=0;x<xs;x++,p++) q[x0+x]=pal[*p]; // copy pixels to target VCL bitmap
 p+=skip; // handle align
 
 y++;
 
 ;
//---------------------------------------------------------------------------

And usage:

BMP bmp;
bmp.load("Anand.bmp");
bmp.draw(target_VCL_bitmap,0,0);

Well as I do have different compiler (but also Borland/Embarcadero) and OS you need to ignore the VCL stuff and replace the rendering with your BGI ... Then change the AnsiString to char* and change the file access routines to your environment (do not forget it should be binary access but IIRC even that did not always work in TCPP had problems with it in past while loading textures into my 3D renderer some control codes where processed regardless of binary access...

Now what you have missing:

1. 
   

   header

   
   
   

   the header of BMP used is different than yours (there are a lot of variations out there that is why I suggested to use PCX instead). So take a look at mine _hdr struct and mimic yours ... The DWORD is unsigned 32 bit int, WORD is unsigned 16 bit int and BYTE is unsigned 8 bit int. I think that TCPP knows them but was ages i code in it so I might be wrong so if the case use relevant data types instead.

   
   
   

   You also do not check for the correct BMP format which is wrong and might lead to crashes so you should at least check the magic number and bpp, compression etc ... like I do

   
   
   

   Also do not forget to set the code alignment to 1 Byte (that is what the #pragma pack are for but not sure if TCPP support that. If not the align should be somewhere in the TCPP IDE settings probably in linker or compiler ...

   
   


2. 
   

   palette

   
   
   

   Your palette loading is suspicious I do not like it ... compare it with mine in the draw routine.

   
   
   

   Also your setting VGA palette routine is wrong see how it should be done. So the target color should be set for each color not just once for whole palette so you need move the out inside loop:

   
   
   

   for(i=0;i<256*3;)
    
    outp(0x03c8,i/3);
    outp(0x03c9,PaletteData[i]); i++; // R
    outp(0x03c9,PaletteData[i]); i++; // G
    outp(0x03c9,PaletteData[i]); i++; // B
    
   

   
   


3. 
   

   Image data

   
   
   

   you are not aligning the scan lines at all that is why your decoded image is shifted (skew like). According to Wiki each scan line is aligned to size:

   
   
   

   (((bits*width)+31)>>5)<<2
   

   
   
   

   So just skip unused BYTEs in the file after each row decoded.

   
   
   

   You also do not use offset which tells you where in the file the image data starts. That is important because the image data can be anywhere not just directly after palette as there might be more data present in the file like important colors etc ...

   
   

Also as you can see I loaded whole image into memory and decode from there. As you are in 16bit environment you might not want to do this as your OS might prevent you from allocating as much memory and also you are limited in memory size quite a lot... But I coded the whole stuff so I do not go back and forward so you should have no problems to port it to decoding directly from file like you have now ...

[Edit1]

here I dig some ancient example of file access from TCPP:

#include <stdio.h>
FILE *hnd;
BYTE data[256];
if ((hnd=fopen("texture.txr", "rb")) == NULL) return; // open file for read binary (not sure with the "b" check in build help)
fread(data,256,1,hnd); // read 256 of 1 BYTES into data array
fclose(hnd); // close file

just verify the usage with your inbuild help (CTRL+F1 while cursor is on a keyword there you will also see which include it needs if stdio is not the one) as I used this ~20 years ago and do not remember exactly... You will also need seek I think its called fseek and parameters are similar to mine FileSeek.

[Edit2] from your updated code its obvious you just copy paste code without thinking...

I managed to code this in TCPP+DOSBOX (ouch man that was pain in the ass as DOSBOX keyboard conflicts borland shortcuts ...)

You did not check the inbuild TCPP help and did not port the stuff correctly. For example yours fseek does not return file size like mine which you would detect right away if you try to debug (F8/F7) ... So here my new C++ (TCPP compatible) code for this:

//---------------------------------------------------------------------------
#include <stdio.h>
#include <conio.h>
//---------------------------------------------------------------------------
typedef unsigned long DWORD;
typedef unsigned int WORD;
typedef unsigned char BYTE;
//---------------------------------------------------------------------------
char far* scr; // VGA screen
const _sx= 320; // physical screen size
const _sy= 200;
void gfxinit()
 
 asm mov ax,19
 int 16
 
 scr=(char far*)0xA0000000;
 
void gfxexit()
 
 asm mov ax,3
 int 16
 
 
void clrscr()
 
 asm push es
 mov ax,0xA000
 mov es,ax
 mov di,0x0000
 sub ax,ax
 mov cx,32000
 rep stosw
 pop es
 
 
void putpixel(int x,int y,char c)
 
 unsigned int adr;
 if ((x<_sx)&&(x>=0))
 if ((y<_sy)&&(y>=0))
 
 adr=x+(y*_sx);
 scr[adr]=c;
 
 
//---------------------------------------------------------------------------
class BMP
 
public:
 BYTE *data;
 DWORD size;
 #pragma pack(push,1)
 struct _hdr
 
 char ID[2];
 DWORD size;
 DWORD reserved1; // ?
 DWORD offset;
 DWORD reserved2; // ?
 DWORD width,height;
 WORD planes;
 WORD bits;
 DWORD compression;
 DWORD imagesize;
 DWORD xresolution,yresolution;
 DWORD ncolors;
 DWORD importantcolors;
 ;
 #pragma pack(pop)
 BMP() data=NULL; free(); 
 ~BMP() free(); 
 void free() if (data) delete[] data; data=NULL; size=0; 
 void load(char* filename);
 void draw(int x0,int y0);
 ;
//---------------------------------------------------------------------------
void BMP::load(char* filename)
 
 FILE *hnd;
 free();
 if ((hnd=fopen(filename, "rb")) == NULL) return; // open file for read binary (not sure with the "b" check in build help)
 _hdr hdr;
 hdr.ID[0]=0;
 hdr.ID[1]=0;
 hdr.size=0;
 fread(&hdr,sizeof(_hdr),1,hnd); // read BMP header into memory
 if (hdr.ID[0]=='B')
 if (hdr.ID[1]=='M')
 size=hdr.size; // get file size
 fseek(hnd,0,0); // seek back to start
 data=new BYTE[size];
 if (data==NULL) // not enough memory or empty file
 
 size=0;
 fclose(hnd);
 return;
 
 fread(data,size,1,hnd); // read BMP into memory
 fclose(hnd); // close file
 
//---------------------------------------------------------------------------
void BMP::draw(int x0,int y0)
 
 _hdr *hdr=(_hdr*)data;
 int x,y,xs,ys,skip;
 BYTE *p;
 if (size<2) return;
 if (hdr->ID[0]!='B') return; // check magic number
 if (hdr->ID[1]!='M') return;
 if (hdr->planes!=1) return; // check format
 if (hdr->bits!=8) return;
 if (hdr->compression!=0) return;
 // palette
 p=data+sizeof(_hdr);
 for (x=0;x<256;x++)
 
 BYTE r,g,b;
 b=*p>>2; p++;
 g=*p>>2; p++;
 r=*p>>2; p++;
 p++;
 outp(0x3C8,x);
 outp(0x3C9,r);
 outp(0x3C9,g);
 outp(0x3C9,b);
 
 // image
 xs=hdr->width;
 ys=hdr->height;
 p=data+hdr->offset;
 skip=(((hdr->bits*hdr->width)+31)>>5)<<2; // compute scanline align
 skip-=hdr->width;
 for (y=0;y<ys;y++,p+=skip)
 for (x=0;x<xs;x++,p++)
 putpixel(x0+x,y0+ys-y-1,*p);
 
//---------------------------------------------------------------------------
void main()
 
 BMP bmp;
 bmp.load("C:\Anand.BMP");
 gfxinit();
 clrscr();
 bmp.draw(0,16);
 // draw palette
 for (int x=0;x<256;x++)
 for (int y=0;y<8;y++)
 putpixel(x,y,x);
 getch();
 getch();
 getch();
 gfxexit();
 
//---------------------------------------------------------------------------

I do not use BGI as I hate it instead I used direct memory access and VGA mode 13h but I code it so its similar to your BGI so you need to port that (remowing the gfxinit/exit and putpixel function bodies) if you want to use the BGI instead.

I placed the BMP directly into C: so I do not need to worry about exe local paths ... You did have a lot of bugs in there like discarted data for BMP storage, wrong palette code etc ... But the biggest bug you got was BYTE definition as yours was 16 bit instead of 8 bit messing up everything... The code above works for me with this output:

As you can see I also render the palette for visual check an I got more getch() calls as the DOSBOX bugged keyboard (probably because of CPU Clock tics timing control) drive me crazy ...