If the preprocessor symbol SDLRENDERING is defined the code operates as
it previously did. In the absence of that, we process the Lisp bitmap
into an intermediate form (as before) but then use SDL bitblt to
redraw the intermediate form on the window's surface.
On startup, bitblt calls may be made for the original screen size
and if the new screen size is smaller than that, we must ensure
that damage notifications are contained within the new screen.
Move definition of min() so we can use it in sdl_notify_damage()
Build with cmake. This will create a new backend (ldesdl).
- Resolution can only be set by editing the variables in sdl.c.
- Key repeat does not work.
- Still problems with keysyms that implicitly contain modifiers.
- The entire screen is bitblted onto the SDL display every frame.
Support keyboard, and work on mouse.
Kind of working...
Fix display resolution problems.
The Lisp implementation distinguishes between 0 and NIL as the result of
the gcscan1/gcscan2 opcodes, however the C implementation did not, since
NIL and 0 are indistinguishable.
CSTKPTR is "LispPTR *" while CurrentStackPTR is "DLword *", cast to "void *" to
silence the warning, add comment pointing out size difference to explain the
"- 1" vs "+ 2" adjustments when saving/restoring.
Creating a free block or guard block on the stack with an odd number of 16-bit words
will cause the system to break badly. Always check that and report an error.
Because the stack pointer is declared as "DLword *" (16-bit) for pointer arithmetic,
although it is always maintained as a pointer to a 32-bit boundary, the compiler generates
spurious warnings on casting the stack pointer to structures that require 32-bit alignment.
Silence those warnings by casting through (void *).
The "fillpointer" and "totalsize" fields of the array header and the "offst"
of the sequence descriptor were declared as LispPTR, an unsigned type that
represents an offset into the Lisp memory, however the Lisp datatype
declaration indicates that these are FIXP (int32_t) rather than pointers.
