Curious anomoly in allegro.

This is a discussion on Curious anomoly in allegro. within the Game Programming forums, part of the General Programming Boards category; Ok so I decided to write some code to place a bunch of bitmap files into one FGD(fixed game data) ...

  1. #1
    Registered User ~Kyo~'s Avatar
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    Question Curious anomoly in allegro.

    Ok so I decided to write some code to place a bunch of bitmap files into one FGD(fixed game data) file just for fire transfer's sake from a server to client update kinda deal I figured plain text would work great. This code though once we kick into the compression function decides to rename my filename variable say I pass in Slime.bmp I end up with S< at the end and a program crash. Anyone see something I am missing? Kinda late so maybe I am overlooking something simple...


    Code:
    #include <iostream>
    #include <fstream>
    #include <string.h>
    #include <allegro.h>
    #include <winalleg.h>
    
    using namespace std;
    void compress(char *);
    
    ofstream FGD_FILE;
    
    int main(int argc, char *argv[])
    {
        FGD_FILE.open("Compressed.fgd");
        FGD_FILE<<argc-1<<endl;
        if(!install_allegro(SYSTEM_NONE,&errno,atexit))
        if(argc > 1)
        {
            for(int comp = 1;comp < argc;comp++)
            {
                compress(argv[comp]);
            }
        }else
        {
            cout<<"Files to compress are not specified."<<endl;
        }
        FGD_FILE.close();
    	return 0;
    }
    END_OF_MAIN();      //allegro specific to correct for winapi's main() function.
    
    void compress(char *filename)
    {
        BITMAP *bmp;
        RGB *palette;
        char *isgoodfile = strstr(filename,".bmp");
        
        if(isgoodfile != NULL)//non null if it is a bitmap or has .bmp in it at least.
        {
            bmp = load_bitmap(filename,palette);
            //CHANGES THE NAME HERE
            if (!bmp)
            {
                cout<<"Problem loading bitmap: "<<filename<<endl
                    <<"Compression aborted check file extention is a .bmp file"<<endl;
            }else
            {
                int color_locked = -1;      //technically valid for r=255 g=255 b=255 and a=255
                int looped = 1;
                FGD_FILE<<filename<<" "<<bmp->w<<" "<<bmp->h<<endl;
                for(int y = 0;y < bmp->h;y++)
                {
                    for(int x = 0;x < bmp->w;x++)
                    {
                        if(color_locked != getpixel(bmp,x,y))
                        {
                            if(color_locked != -1)FGD_FILE<<looped<<" "<<color_locked<<" ";
                            color_locked = getpixel(bmp,x,y);
                            looped = 1;
                        }else looped++;
                    }
                }
                FGD_FILE<<looped<<" "<<color_locked<<endl<<endl<<endl;
            }
            cout<<"Compressed and added file: "<<filename<<endl;
            destroy_bitmap(bmp);
        }else cout<<"Unable to verify file maybe it isn't a bitmap?"<<endl;
    }

  2. #2
    Frequently Quite Prolix dwks's Avatar
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    I've never used allegro, but notice that while the second parameter to load_bitmap() is actually an RGB*, the example in the docs actually uses a PALETTE. Allegro Manual: Loading image files

    Clicking on the links, a PALETTE is actually an array instead of just a pointer. What's probably happening is that since you pass in just an RGB* pointer, which could be pointing anywhere, you get memory corruption. Try using a PALETTE or, if you don't care about the palette at all, pass in a NULL pointer (according to the docs this is allowed).
    dwk

    Seek and ye shall find. quaere et invenies.

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  3. #3
    Registered User ~Kyo~'s Avatar
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    While this is true you can actually pass NULL to it and have it work fine... Yea ok so you were cut short on my e-mail note lol NULL works fine more often than not I don't remember what I did to fix it. but it is fixed moved onto other things sorry...

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