[rmodels] tinyobj_loader_c.h fails to load .mtl if .obj uses \r\n as EOL

[SuperUserNameMan]

Hello,

Before redirecting me to open an issue on tinyobjloader-c, please note that the version of tinyobjloader-c used by Raylib is outdated, and it can't be directly updated because of API changes.

So, either rmodels.h needs to be updated alongside external/tinyobj_loader_c.h, either Raylib keeps the outdated version of tinyobj_loader_c.h and we have to fix it ourselves.

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The bug :

Not sure if it's directly related to #3398, but i've just found a bug in the (outdated) version of tinyobj_loader_c.h used by Raylib regarding the end of lines format used in the .obj and .mtl files.

I'm on Linux, and I exported my .obj/.mtl from Wings3D which (unexpectedly) uses the MS-Windows' \r\n end of line format.

It appears that this version of tinyobj_loader_c.h does not handle \r\n correctly.

The filename sent to tinyobj_parse_and_index_mtl_file() from tinyobj_parse_obj() will contains a \r as the last character (before the \0), which prevents the .mtl file from loading.

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The obvious workaround is to convert \r\n to \n in my .obj/.mtl files.

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Edit : the quickfix i provided before this edit was not enough, there are other issues that leads to segfaults

[SuperUserNameMan]

Ok, here is a better quick fix to be inserted here :

raylib/src/external/tinyobj_loader_c.h

Lines 1267 to 1275 in f721429

	/* Fill line infos. */
	for (i = 0; i < end_idx; i++) {
	if (is_line_ending(buf, i, end_idx)) {
	line_infos[line_no].pos = prev_pos;
	line_infos[line_no].len = i - prev_pos;
	prev_pos = i + 1;
	line_no++;
	}
	}

---

    /* Fill line infos. */
    for (i = 0; i < end_idx; i++) {
      if (is_line_ending(buf, i, end_idx)) {
        line_infos[line_no].pos = prev_pos;
        line_infos[line_no].len = i - prev_pos;

// ---- QUICK BUG FIX : https://github.com/raysan5/raylib/issues/3473
        if ( i > 0 && buf[i-1] == '\r' ) line_infos[line_no].len--; 
// --------

        prev_pos = i + 1;
        line_no++;
      }
    }

[raysan5]

@SuperUserNameMan Actually, tinyfiledialogs-c library should be updated to latest stable version but in the meantime, feel free to send proposed fix as a PR for integration.

[SuperUserNameMan]

@raysan5 : ok, done

[raysan5]

@SuperUserNameMan Merged!