With vsync enabled the render times of consecutive frames can diverge.
The first frame arrives right at the next display frame and is rendered
without waiting time. The next frame has to wait 20ms. The leads to some
problems with the move prediction if the client is asynchronous. Fix
this by capping the desired frame rate at the display refresh rate. Also
make sure that the network framerate is never higher then the renderer
framerate.
With the commit the timing is always correct:
* With no limit as much frames as possible are rendered. In this case
rfps > nfps and everything's good.
* With vsync enabled rfps > nfps or rfps == nfps is given. Also rfps
will never exceed the display refresh rate.
* On slow hardware either rfps > nfps or an implicit rfpc == nfps is
given.
While the bugfix in a6f4a3b made the steping prediction working for
stairs, elevators are still stuttering. r1q2s code solves this problem
and is a little bit faster. Use it instead.
Yesterday I chose setting cl_async to 0 since I saw some movement
changed with the async client enabled. Especially when clipping against
bevels the game started to stutter and there were small rendering
problems. After some debugging I realized that it is caused by slight
inaccuracies in the move prediction. When cl_maxfps is too low, the
movement error between two render frames becomes to big, leading to
misspositions. There're two ways to solve this problem:
* Processing more client frames. Most async clients I've looked on
process 60 or even 90 render frames. I chose to stay at 60 since
I was unable to see differences with higher rates.
* Changed to pmove.c and the pmove_t struct. Some multiplayer focused
clients go that way. But there's a very high of breaking singleplayer
movement and pmove_t is part of the server <-> game API. Additionally
the network code must / should be altered. So this is unsuitable for
YQ2.
Please note that there's still a change in movement. Before 4ae8706 and
when cl_async is set to 0 movement is dependend on the render framerate.
At low framerate bevel clipping isn't working too good, at high
framerates prediction causes physics changes like the famous 125hz bug.
With cl_async set to 1 the network framerate is stable, leading to a
more consistant behahiour.
Most (all?) clients implement the synchronous and the asynchronous
client by seperate code pathes. Instead of doing that we force the
asynchronous path to process one network frame for each render frame.
We're missusing the current frame to pass data from the input subsystem
to the movement prediction without a server frame. While we can use the
current frame for the movements itself, it's not finished and thus
unsuitable for stair step prediction. Also oldframe is determined
wrongly. As a result the player "jumps" over stairs.
This is a slighty revised version of id Software original code. Icculus
code may have some advantages on broken drivers or underpowered GPUs.
Today it's just a performance hook. This is a first step in fixing #147.
This is more than enough for everyone and prevents wasting CPU time.
Without this change as many client frames as possible are rendered,
Quake II uses a complete core.
This is based on work submitted by Scott "pickle" Smith. It's said that
vertex arrays are somewhat faster and more compatible than the old way.
This may remove support of some very, very old GPUs like the Riva128.
This is more less cosmetics since gl_tex_solid_format == GL_RGB and
GL_LIGHTMAP_FORMAT == GL_RGBA. No measurable FPS change on Nvidia and
Intel. Based upon the OpenGL ES patch by Scott "pickle" Smith.
This is based upon the original OpenGL ES patch by Scott "pickle"
Smith. This change gives about the same frame rate on an 750TI but
about 3% more frames on an Ivy Bridge IGP with Mesa3D...
This is largely based upon the cl_async 1 mode from KMQuake2, which in
turn is based upon r1q2. The origins of this code may be even older...
Different to KMQuake2 the asynchonous mode is not optional, the client
is always asynchonous. Since we're mainly integrating this rather
fundamental change to simplify the complex internal timing between
client, server and refresh, there's no point in keeping it optional.
The old cl_maxfps cvar controls the network frames. 30 frames should be
enough, even Q3A hasn't more. The new gl_maxfps cvar controls the render
frames. It's set to 95 fps by default to avoid possible remnant of the
famous 125hz bug.
I'm not quite sure if this really makes a difference. But it's the only
idea I have regarding several "Quake II hangs at shutdown when OpenAL is
run with Pulseaudio backend" bugs.
The game code does not include common.h, so it needs to redo this
part for builds without SOURCE_DATE_EPOCH, where BUILD_DATE will
not have been passed in from the outside.
Signed-off-by: Simon McVittie <smcv@debian.org>
In Linux distributions, having the executable depend on the right
libraries and arrange for them to be installed is straightforward,
and there's a lot of infrastructure for tracking which library
version a particular executable needs, including making sure we have
a version that contains all of the symbols that were used. Loading
libopenal at runtime defeats that infrastructure.
The ability to substitute a different-but-compatible libopenal,
or operate with reduced functionality without libopenal, might
still be desirable for generic/portable binary releases.
The CMake build system already linked the executable to
${OPENAL_LIBRARY} anyway, so it is already a hard dependency in that
build system.
For deterministic/reproducible builds (where the same source and
toolchain can be verified to produce the same binary, allowing
maliciously substituted binaries to be detected) it is desirable to
take the software's idea of the build date from the build system;
otherwise, the real-time clock at the time of building affects the
result, making it non-reproducible.
SOURCE_DATE_EPOCH is a distribution-neutral specification for how
to do that. It is meant to be set by meta-build systems such as
dpkg or RPM, using a date/time that is already part of the source code,
for example the date of the latest git commit, the date in
the package's debian/changelog, or the date in the RPM spec file.
See https://reproducible-builds.org/specs/source-date-epoch/ for the
specification of SOURCE_DATE_EPOCH, or https://reproducible-builds.org/
for more information on reproducible builds in general.
