Re: [AD] Problem loading 32bit bmp file

[Evert Glebbeek <eglebbk@xxxxxxxxxx>]

On Wednesday 17 August 2005 14:21, Michal Molhanec wrote:
> That's no surprise. The Allegro docs says:
> 
> BITMAP *load_bmp(const char *filename, RGB *pal);
> Loads a 256-color or 24-bit truecolor Windows or OS/2 BMP file.
> 
> So you cannot expect that it will load 32-bit bitmap.

Hmm... the docs are incorrect anyway, since Allegro can load 16 bit BMP 
files too (at least, looking at the code suggests that it can, I haven't 
tried it). But you're right in that it doesn't say it can read 32 bit BMP 
files.
Anyway, the fix appears to be simple enough. Proposed patch attached.

Evert

Index: src/bmp.c
===================================================================
RCS file: /cvsroot/alleg/allegro/src/bmp.c,v
retrieving revision 1.17
diff -u -r1.17 bmp.c
--- src/bmp.c	19 Mar 2005 11:15:06 -0000	1.17
+++ src/bmp.c	17 Aug 2005 12:30:32 -0000
@@ -276,6 +276,27 @@
 
 
 
+/* read_32bit_line:
+ *  Support function for reading the 32 bit bitmap file format, doing
+ *  our best to convert it down to a 256 color palette.
+ */
+static void read_32bit_line(int length, PACKFILE *f, BITMAP *bmp, int line)
+{
+   int i;
+   RGB c;
+   char a;
+
+   for (i=0; i<length; i++) {
+      c.b = pack_getc(f);
+      c.g = pack_getc(f);
+      c.r = pack_getc(f);
+      a = pack_getc(f);
+      WRITE3BYTES(bmp->line[line]+i*4, makeacol32(c.r, c.g, c.b, a));
+   }
+}
+
+
+
 /* read_bitfields_image:
  *  For reading the bitfield compressed BMP image format.
  */
@@ -353,6 +374,10 @@
 	 case 24:
 	    read_24bit_line(infoheader->biWidth, f, bmp, infoheader->biHeight-i-1);
 	    break;
+
+	 case 32:
+	    read_32bit_line(infoheader->biWidth, f, bmp, infoheader->biHeight-i-1);
+	    break;
       }
    }
 }
@@ -592,6 +617,8 @@
       bpp = 24;
    else if (infoheader.biBitCount == 16)
       bpp = 16;
+   else if (infoheader.biBitCount == 32)
+      bpp = 32;
    else
       bpp = 8;