Performance can still be crudely measured by turning off
the framelimit and observing the FPS count. For everything
else, there's always callgrind / apitrace.
GL entrypoint resolution is now done manually. This has a couple
immediate benefits, such as not having to retrieve hundreds of
functions pointers that we'll never use. It's also nice to have
an exact overview of all the entrypoints used by mkxp.
This change allows mkxp to run fine with core contexts, not sure
how relevant that is going to be in the future.
What's noteworthy is that _all_ entrypoints, even the ones core
in 1.1 and guaranteed to be in every libGL, are resolved
dynamically.
This has the added benefit of not having to link directly against
libGL anymore, which also cleans up the output of `ldd` quite
a bit (SDL2 loads most system deps dynamically at runtime).
GL headers are still required at build time.
When using something like Valgrind that will run
mkxp 20 times slower than normal, frame skip will
make the redraw loop completely grind to a halt.
Set 'frameSkip' to false in the config to
avert this.
We didn't account for the spec dictating that
scissor test does affect FBO blit operations,
which resulted in corrupted output if more than
one viewport with an active effect (tone, color)
was created.
The reason I never caught this before must be
that the fglrx-legacy driver is actually bugged
in this aspect and ignores the scissor on blit.
The general rule I'm aiming for is to <> include
system wide / installed paths / generally everything
that's outside the git managed source tree (this means
mruby paths too!), and "" include everything else,
ie. local mkxp headers.
The only current exception are the mri headers, which
all have './' at their front as to not clash with
system wide ruby headers. I'm leaving them be for now
until I can come up with a better general solution.
We now actively track how far behind / in front of an
ideal timestep we are during each frame, and try to
catch up / delay approximate this timing.
Therefore we use more precise timers and sleep functions
(nanosleep if available). We also delay **before** the
final buffer swap so the frame displays at more consistent
points in time.
Not only should this provide a somewhat more consistent
looking map scrolling at lower frame rates, it also
guarantees that we don't fall out of sync eg. with the
Audio during longer cutscenes.
'Graphics.frameReset()' now finally has a function, in
that it resets the ideal timestep approximation, which I
beliefe was also its job in the original RMXP engine.
I'm not sure how well this will work when the frame rate
is set to the monitor refresh rate and vsync is turned on.
Very likely unnecessary frame skips will occur here and there
due to imprecise timers. In the future we should probably
check if the frame rate is equal to or higher than the
monitor rate, and disable frame skip accordingly.
These changes currently break the F2 FPS display (it shows
a value that's slightly too high).
Using "SDL2/SDL_xxx.h" instead of "SDL_xxx.h" caused
the include paths provided by pkg-config to be ignored,
and headers from a standard include path to be used instead.
This should make graphics.cpp somewhat easier to navigate/read.
GL_EXT_timer_query is also made optional, and if it's not present
dummy functions will be called instead.
Jonas Kulla
Edward Rudd