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test_driver: renamed image refuses to load
Member #7,859
October 2006

Because my installation lacks jpeg, I edited some ini files for test_driver. Namely: test_image (removed jpeg sections), and test_prim (changed file name for obp). For the latter of course I also saved a copy of the file in an another format. Still it failed (gracefully) to load the third bitmap. I have tried bmp (24 or 32 bit), and png with some random settings (desperately tried turning down compression). I don't see why the image won't load.
I ran it through gdb, and it justs fails to fopen the third file. (Notice the previous two images were loaded without problem.)
So here's the first few lines of the ini (only first 3 are of importance):


op0= al_draw_bitmap(bkg, 0, 0, 0)
op1= al_build_transform(trans, 320, 240, 1, 1, 1.0)
op4= al_use_transform(trans)

(I asserted the line ending and non-printing characters)
Here's my first attempt at debugging it:

1(gdb) list 220 321 ASSERT(drv); 422 ASSERT(path); 523 ASSERT(mode); 624 725 if (drv->fi_fopen) { 826 f = al_malloc(sizeof(*f)); 927 if (!f) { 1028 al_set_errno(ENOMEM); 1129 } 12(gdb) step 1326 f = al_malloc(sizeof(*f)); 14(gdb) 15al_malloc_with_context (n=28, line=26, 16 file=0x6942d1c8 "D:\\SDevX\\A5\\src\\file.c", 17 func=0x6942d28e "al_fopen_interface") at D:\SDevX\A5\src\memory.c:41 1841 if (mem) 19(gdb) 2044 return malloc(n); 21(gdb) 2245 } 23(gdb) 24al_fopen_interface (drv=0x6942d340, 25 path=0x1dd6fb8 "../examples/data/obp.bmp", mode=0x6316e117 "rb") 26 at D:\SDevX\A5\src\file.c:27 2727 if (!f) { 28(gdb) 2931 f->vtable = drv; 30(gdb) 3132 f->userdata = drv->fi_fopen(path, mode); 32(gdb) 33file_stdio_fopen (path=0x1dd6fb8 "../examples/data/obp.bmp", 34 mode=0x6316e117 "rb") at D:\SDevX\A5\src\file_stdio.c:82 3582 fp = fopen(path, mode); 36(gdb) print path 37$4 = 0x1dd6fb8 "../examples/data/obp.bmp" 38(gdb) print mode 39$5 = 0x6316e117 "rb" 40(gdb) step 4183 if (!fp) { 42(gdb) 4384 al_set_errno(ENOMEM); 44(gdb) list 4579 { 4680 FILE *fp; 4781 4882 fp = fopen(path, mode); 4983 if (!fp) { 5084 al_set_errno(ENOMEM); 5185 return NULL; 5286 } 5387 5488 return fp;

Allegro debug. Build without SSE. MinGW 4.5. Windows 7. I've tried a fresh restart.
The only thing I can think of is some illegal access to memory used by fopen. :-/
Any more sensible ideas?

Arthur Kalliokoski
Second in Command
February 2005

If you swap the order of files around, the third one always fails?

They all watch too much MSNBC... they get ideas.

Peter Wang
Member #23
April 2000

Make sure the obp.bmp exists in the $BUILDDIR/examples/data, where $BUILDDIR is your build directory. It won't work to just have it in the source examples/data directory.

Member #7,859
October 2006

D'OH! Now I feel stupid. I was confused because the ini files are only in the source directory.
Rule #1 of debugging: the least trustworthy needs the closest inspection.

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