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On 2010-08-06, Milan Mimica <milan.mimica@xxxxxxxxxx> wrote:
> Peter Wang wrote:
> > On 2010-08-06, Elias Pschernig <elias.pschernig@xxxxxxxxxx> wrote:
> >>> 2.
> >>> Index: src/opengl/ogl_bitmap.c
> >>> ===================================================================
> >>> --- src/opengl/ogl_bitmap.c (revision 13538)
> >>> +++ src/opengl/ogl_bitmap.c (working copy)
> >>> @@ -561,7 +561,7 @@
> >>> * However if we do that, without NPOT textures, we get some junk at the
> >>> * edges of our bitmaps when we draw them.
> >>> */
> >>> - unsigned char *buf = al_calloc(ogl_bitmap->true_h, ogl_bitmap->true_w);
> >>> + unsigned char *buf = al_calloc(4, ogl_bitmap->true_h * ogl_bitmap->true_w);
> >>> glTexImage2D(GL_TEXTURE_2D, 0, glformats[bitmap->format][0],
> >>> ogl_bitmap->true_w, ogl_bitmap->true_h, 0,
> >>> GL_ALPHA, GL_UNSIGNED_BYTE, buf);
> >>>
> >>> I have hardcoded a "4" there but you get the picture. Valgrind told me about this.
> >
> > Hmm, isn't it correct, since I specified GL_ALPHA, GL_UNSIGNED_BYTE?
> > i.e. for each pixel in the texture I'm only providing the alpha value,
> > each of which is a single byte.
>
> IDK, valgrind says this and i do get artifacts (not in ex_haiku though):
>
> ==3694== Invalid read of size 1
> ==3694== at 0x4028AA9: ???
> ==3694== Address 0x66ade7a is 1 bytes after a block of size 49,761 alloc'd
> ==3694== at 0x40228C9: calloc (in
> /usr/lib/valgrind/x86-linux/vgpreload_memcheck.so)
> ==3694== by 0x80EE26D: al_calloc_with_context (memory.c:83)
> ==3694== by 0x814376C: ogl_upload_bitmap (ogl_bitmap.c:564)
> ==3694== by 0x80C1C2A: al_create_bitmap (bitmap.c:124)
> ==3694== by 0x80C2E32: al_clone_bitmap (bitmap.c:667)
> ==3694== by 0x81468F9: al_grab_font_from_bitmap (fontbmp.c:232)
> ==3694== by 0x81466A0: _al_load_bitmap_font (fontbmp.c:159)
> ==3694== by 0x8146252: al_load_font (font.c:350)
Perhaps it is just over-reading by a few bytes, due to us forgetting
about alignment or something. What is the bitmap size you are loading?
Peter