Windows port

[AltVanguard]

Hi,

I've made a basic Windows port of DM-VIO. I wanted to check how much I have broken in the Linux build (e.g. I most likely broke sse2neon in the CMake), but I regrettably haven't got around to it in the past months so I've decided to open this pull request so you can take a look at it as is. No hard feelings if this doesn't get merged :)

My changes fall into these 3 categories:

• Get dependencies via Conan: This provides a consistent way to acquire dependencies and the same versions of them on all platforms. I updated the build instructions in the readme accordingly. Meanwhile, I modernized the main CMake a tiny bit (e,g, not pulling in *_INCLUDE_DIRs, and instead relying on target_link_libraries). Conan only had a newer version of GTSAM and there were some breaking API changes in it that had to be resolved.
• Use stdlib APIs: This one was pretty straightforward. No new thirdparty dependencies, all Linux APIs were replaced with their standard counterparts.
• Fix warnings: Some warnings actually impacted the ability to link with the library under MSVC, so there are some changes that seem superficial, but were required. I left the less impactful MSVC warnings ignored in the CMake, but of course I recommend removing the ignores and eliminating the warnings themselves.

Let me know if you are interested in this port at all. If you have a specific issue with it, I'll see what I can do about it.

[lukasvst]

Hi,

thanks a lot, it's great to see a version that can work on Windows!

I think merging it with master could be complicated without breaking building on other systems, and unfortunately I'll be very busy the next weeks.

But I think it is already very useful to other people as is, with this PR open :)

[djblazkowicz]

Hello,

I couldn't find a more appropriate discussion thread for this so I thought I'll comment here so that people interested in this might be able to find it.

I am using this fork on Windows, compiled on Windows 10 20H2 with Visual Studio 2019.

When building dm-vio, I was getting a bunch of "M_PI undeclared identifier" errors, which I was able to fix by adding _USE_MATH_DEFINES to preprocessor definitions.

With the associated fork of Pangolin 0.6, I was getting build failures due to errors in include\mpark\variant.hpp.
Related issue and fix: stevenlovegrove/Pangolin#609

When using the TUMVI datasets, I noticed that the symbolic link in the dso/cam0 folders do not work on windows, so I had to move the images folder to dso/cam0 to solve the problem.

Once all this was sorted, I was able to successfully run dmvio_dataset.exe with the following windows command line

dmvio_dataset.exe ^
files=path to dataset/dso/cam0/images ^
vignette=path to dataset/dso/cam0/vignette.png ^
imuFile=path to dataset/dso/imu.txt ^
gtFile=path to dataset/dso/gt_imu.csv ^
calib=path to dm-vio/configs/tumvi_calib/camera02.txt ^
gamma=path to dm-vio/configs/tumvi_calib/pcalib.txt ^
imuCalib=path to dm-vio/configs/tumvi_calib/camchain.yaml ^
mode=0 ^
use16Bit=1 ^
preset=0 ^
nogui=0 ^
resultsPrefix=path to results ^
settingsFile=path to dmvio/configs/tumvi.yaml ^
start=2 ^
useimu=1

I hope anyone interested may find this useful!