method as in /bin/sh.
We still do technically undefined things in the signal handler, but it
is safe in practice to access state that is protected by INTOFF/INTON.
In a recent commit, I sprinkled VGLMouseFrozen++/-- operations in
places that need INTOFF/INTON. This prevented clobbering of pixels
under the mouse, but left mouse signals deferred for too long. It is
necessary to call the signal handler when the count goes to 0. Old
versions did this in the unfreeze function, but didn't block actual
signals, so the signal handler raced itself. The sprinkled operations
reduced the races, but when then worked to block a race they left
signals deferred for too long.
Use INTOFF/INTON to fix complete loss of mouse signals while reading
the mouse status. Clobbering of the state was prevented by SIG_IGN'ing
mouse signals, but that has a high overhead and broke more than it
fixed by losing mouse signals completely. sigprocmask() works to block
signals without losing them completely, but its overhead is also too
high.
libvgl's mouse signal handling is often worse than none. Applications
can't block waiting for a mouse or keyboard or other event, but have
to busy-wait. The SIG_IGN's lost about half of all mouse events while
busy-waiting for mouse events.
Reading of single pixels didn't look under the cursor.
Copying of 1x1 bitmaps didn't look under the cursor for either reading
or writing.
Copying of larger bitmaps looked under the cursor for at most the
destination.
Copying of larger bitmaps looked under a garbage cursor (for the Display
bitmap) when the destination is a MEMBUF. The results are not used, so
this only wasted time and flickered the cursor.
Writing of single pixels looked under a garbage cursor for MEMBUF
destinations, as above except this clobbered the current cursor and
didn't update the MEMBUF. Writing of single pixels is not implemented
yet in depths > 8. Otherwise, writing of single pixels worked. It was
the only working case for accessing pixels under the cursor.
Clearing of MEMBUFs wasted time freezing the cursor in the Display bitmap.
The fixes abuse the top bits in the color arg to the cursor freezing
function to control the function. Also clear the top 8 bits so that
applications can't clobber the control bits or create 256 aliases for
every 24-bit pixel value in depth 32.
Races fixed:
Showing and hiding the cursor only tried to avoid races with the mouse
event signal handler for internal operations. There are still many
shorter races from not using volatile or sig_atomic_t for the variable
to control this. This variable also controls freezes, and has more
complicated states than before.
The internal operation of unfreezing the cursor opened a race window
by unsetting the signal/freeze variable before showing the cursor.
depths for the source and target are not supported. The bits for higher
numbered planes (mostly for red) were either not copied or were copied to
lower numbered planes for nearby pixels.
Quick fix for creation of mouse cursor bitmaps in all depths. This fix is
only complete for the default lightwhite cursor with a black frame.
Even the lightwhite and black colors are hard to find. The templates
use 0xff for lightwhite, but that means brightblue in the simplest mode
(Truecolor depth 24). Other modes are even more complicated -- they are
singly or doubly indirect throught palette(s) and changing of the palettes
by applications is supported.
Details:
Replicate the template value for Truecolor modes to fill out the target
depth (and more for depths not a multiple of 8). Do this for every
drawing of the cursor so that it sort of works for mouse cursor bitmaps
set by applications.
Use 0xf for lightwhite in most other modes. Only do this for the
default cursor so that it doesn't affect mouse cursor bitmaps set by
applications. 0xf mostly works because it was originally for CGA
lightwhite and is emulated using 1 or 2 indirections on EGA and VGA.
0x3f (EGA white) and 0xff (VGA black) direct palette indexes mostly
don't work since backwards compatibility inhibits or prevents them
representing lightwhite. But 0x3f (EGA white) must be used for mode
37 (VGA_MODEX) (320x240x8 V) since this mode is closer to EGA than VGA.
VGLBitmapString() and VGLSetBorder() so as to not truncate to 8 bits.
Complete the corresponding fix for VGLGetXY() and VGLPutXY() (parts
of the man page were out of date).
Support for 16-bit and 32-bit Truecolor modes was supposed to be
complete in r70991 of main.c and in nearby revisions for other files, but
it was broken by the overruns in most cases (all cases were the mouse
is enabled, and most cases where bitmaps are used). r70991 also
uninintentionally added support for depths 9-15, 17-23 and 25-31.
Depth 24 was more obviously broken and its support is ifdefed out. In
the other ranges, only depth 15 is common. It was broken by buffer
overruns in all cases.
bitmap.c:
- the static buffer was used even when it was too small (but it was
large enough to often work accidentally in depth 16)
- the size of the dynamically allocated buffer was too small
- the sizing info bitmap->PixelBytes was not inititialzed in the bitmap
constructor. It often ended up as 0 for MEMBUFs, so using it in more
places gave more null pointer accesses. (It is per-bitmap, but since
conversion between bitmaps of different depths is not supported (except
from 4 bits by padding to 8), it would work better if it were global.)
main.c:
- depths were rounded down instead of up to a multiple of 8, so PixelBytes
was 1 too small for depths above 8 except 16, 24 and 32.
- PixelBytes was not initialized for 4-bit planar modes. It isn't really
used for frame buffer accesses in these modes, but needs to be 1 in
MEMBUF images.
mouse.c:
- the mouse cursor buffers were too small.
vgl.h:
- PixelBytes was not initialized in the static bitmap constructor. It
should be initialized to the value for the current mode, but that is
impossible in a static constructor. Initialize it to -1 so as to
fail if it is used without further initialization.
All modes that are supposed to be supported now don't crash in
nontrivial tests, and almost work. Missing uses of PixelBytes now
give in-bounds wrong pointers instead of overruns. Misconversions of
bitmaps give multiple miscolored mouse cursors instead of 1 white one,
and similarly for bitmaps copied through a MEMBUF.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using mis-identified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Replace all in-tree uses with necessary subset of <sys/{fb,kb,cons}io.h>.
This is also the appropriate fix for exo-tree sources.
Put warnings in <machine/console.h> to discourage use.
November 15th 2000 the warnings will be converted to errors.
January 15th 2001 the <machine/console.h> files will be removed.
It adds new functions and extend some structures and can handle
VESA modes.
- Update the man page.
- Bump the library version number.
(The old version will be added to compat3x.)
