Re: [AD] Line clipping bug found

[aj <aj@xxxxxxxxxx>]

why is 16bit mode set, then palettes manipulation ?

i think the set_clip()  is also inclusive of the x2,y2  so SCREEN_W 
is  out-of-bounds.





At 04:10 AM 8/01/2004 -0800, you wrote:
> Hello,
>
> I have found a problem with line clipping in WIP
> 4.1.12.  Some code to demonstrate:
>
> /*
>  *    Program showing line drawing problem
>  *
>  *    Different pixels are drawn for a given line
> depending on clipping.
>  *    This is shown by drawing a line, changing the
> clipping and then
>  *    drawing the same line again.  The clipping
> region should be blank.
>  *
>  *    The bug is in 4.1.12 but not in 4.1.11
>  *
>  *    Doug Eleveld
>  */
>
>
> #include "allegro.h"
>
>
>
> int main(int argc, char *argv[])
> {
>    int i;
>    PALETTE the_palette;
>
>    if (allegro_init() != 0)
>       return 1;
>    install_keyboard();
>
>    set_color_depth(16);
>    if (set_gfx_mode(GFX_AUTODETECT, 320, 200, 0, 0) !=
> 0) {
>       if (set_gfx_mode(GFX_SAFE, 320, 200, 0, 0) != 0)
> {
>          set_gfx_mode(GFX_TEXT, 0, 0, 0, 0);
>              allegro_message("Unable to set any graphic
> mode\n%s\n", allegro_error);
>              return 1;
>       }
>    }
>
>    generate_332_palette(the_palette);
>    set_palette(the_palette);
>
>    clear_to_color(screen, makecol(0,0,0));
>
>    for (i=0; i<100; i++) {
>        int x1 = rand() % SCREEN_W;
>        int y1 = rand() % SCREEN_H;
>        int x2 = rand() % SCREEN_W;
>        int y2 = rand() % SCREEN_H;
>
>        set_clip(screen, 0, 0, SCREEN_W, SCREEN_H);
>        drawing_mode(DRAW_MODE_SOLID, screen, 0, 0);
>        line(screen, x1, y1, x2, y2,
> makecol(255,255,255));
>
>        set_clip(screen, 50, 50, 150, 150);
>        drawing_mode(DRAW_MODE_XOR, screen, 0, 0);
>        line(screen, x1, y1, x2, y2,
> makecol(255,255,255));
>    }
>
>    set_clip(screen, 0, 0, SCREEN_W, SCREEN_H);
>    drawing_mode(DRAW_MODE_SOLID, screen, 0, 0);
>    rect(screen, 49, 49, 151, 151, makecol(0,255,0));
>    textout_ex(screen, font, ALLEGRO_VERSION_STR, 0, 0,
> makecol(255,255,255), makecol(0,0,0));
>    textout_ex(screen, font, "Box should be empty", 0,
> 16, makecol(255,255,255), makecol(0,0,0));
>
>    readkey();
>    return 0;
> }
>
> END_OF_MAIN();
>
>
> __________________________________
> Do you Yahoo!?
> Yahoo! Hotjobs: Enter the "Signing Bonus" Sweepstakes
> http://hotjobs.sweepstakes.yahoo.com/signingbonus
>
>
> -------------------------------------------------------
> This SF.net email is sponsored by: Perforce Software.
> Perforce is the Fast Software Configuration Management System offering
> advanced branching capabilities and atomic changes on 50+ platforms.
> Free Eval! http://www.perforce.com/perforce/loadprog.html
> --
> https://lists.sourceforge.net/lists/listinfo/alleg-developers