Category Archives: C#

Giving up on MongoDB from C++ for now

I’ve tried building this thing using CMake and Visual Studio and CMake seems to keep picking up cygwin headers for Visual Studio builds and I can’t seem to make things better. For now not worth the pain. I’m probably going back to C# with C++/CLI to get this working with C APIs and C# for MongoDB access.

I’m certain that I could get this building with enough effort. The code looks reasonable and I can put together the projects myself. I’m not all that inclined to go there though as I’d have to re-do this every time through. I’m not familiar enough with CMake to try modifying that part of the process.

Ok…not quite giving up. I did find that CMake appears to be adding a cygwin header folder to the projects. If I manually remove this from them the build goes further. The default build configuration appears to be 32 bit which is also an issue for me. Perhaps I’ll do a little more before I completely give up.

Unity, Daydream, VIVE and some more VR

Spent some time after hours doing some work with unity and blender with my friends Sam and Malcolm. We’re all trying to become more proficient in putting together virtual spaces and using these tools to build more interesting assets.

I’ve got a daydream headset now to complement my HTC Vive. I really want to reach the point where I can build things that work on flat PC screens and both the vive and daydream (cardboard might be nice as well, but it is less interesting as its control capabilities are quite limited).

Malcolm and Sam are focusing on the daydream for now. We’re all going after different sorts of content. I’m aiming for a computer mediated, turn based, multi-player game inspired by some of the old board wargames I played in high school and college.

Malcolm and Sam helped me get my phone and computer loaded with the daydream development tools and mostly running (I left my daydream headset at home so I’ll have to fill in the remaining details later). I still have quite a bit of coding to do in order to get a working initial environment for my game going. I’m also going to have to work to keep the graphical intensity at a level that the phones can handle…I expect the PC and vive will want a different sort of assets for practical purposes.

Once the base game is working, I’ll need to put together a PHP/MySQL back-end to connect the game-board implementation to other players. Details here remain to be worked out, but I expect the initial version will be hosted here with some hand coded PHP managing the back-end. I am still split on how to partition up the game rules logic. Ideally the local copy of the game would only handle display and rendering while the server side code would handle random number generation and rules logic. Placing that much complexity in the PHP code may not be an ideal solution…I’ll have to play with things more in order to be sure.

Looking at building a simple game with unity

I’m looking at building a game similar to stellar conquest (without borrowing any copyrighted content) using unity and then setting up a multiplayer capability through an internet connection (likely my hosting with some PHP persisting moves to a MySQL database).

I’ve got the basics figured out for laying out the playing surface and it looks as if prefabs work for creating stars, planets and ships. I can see how the player interface would work in VR (either room scale or three axis) but I’m going to have to dig in to work out hit-testing for on-screen mouse activity.

I’m going to be thinking about how to handle star generation. The game that is providing the inspiration used a fixed map with the star located at mostly symmetrical positions. I’m inclined to have my game place the stars using a random number generator but with a defined distribution of star types to ensure some level of balance.

I’m going to do the same sort of thing for planets…not cards from a deck as with the board game but again, randomized with appropriate probabilities to yield the right sorts of planet mix.

I think the next step is probably to build the star cluster and scatter some colored lights about through space…I’m really tempted to go with a three dimensional star cluster for the final version if VR is the main target.

More adventures with C++/CLI

I’ve been working with C++/CLI to get access to native API functionality from C# some more lately. I’ve been running into cases where something compiles flawlessly when I create the project but then fails miserably when pulled from GIT clean and rebuilt. I’m looking at various build issues that might be contributing to this and will hopefully find the right recipe soon.

Some notes here related to parts that matter and APIs that I’m looking to use…half of this for my own reference as I mess with solutions to see what works:

Marshaling strings the (relatively) easy way:

 #include <msclr/marshal.h>

System::String^ myPath = "ABC";
std::wstring path = msclr::interop::marshal_as(myPath);

File information:

typedef struct _FILE_ID_INFO {
ULONGLONG VolumeSerialNumber;
FILE_ID_128 FileId;
} FILE_ID_INFO, *PFILE_ID_INFO;

FILE_ID_INFO info;

BOOL ok = GetFileInformationByHandleEx(myHandle, FileIdInfo, &info, sizeof(info));

Alternate string marshaling:

inline void MarshalString(String ^ s, std::wstring& os) {
using namespace Runtime::InteropServices;
const wchar_t* chars =
(const wchar_t)Marshal::StringToHGlobalUni(s)).ToPointer();
os = chars;
Marshal::FreeHGlobal(IntPtr((void)chars));
}

Volume information:

BOOL ok = GetVolumeInformationW(path.c_str(),
volumeNameBuffer, MAX_PATH + 1,
&serial,
&pathLength,
&flags,
filesSystemName, MAX_PATH + 1);

File attributes (can be used on c:\ to find things like volume creation time stamp)

WIN32_FILE_ATTRIBUTE_DATA info;     
BOOL ok(GetFileAttributesExW(path.c_str(),
  GetFileExInfoStandard,
static_cast<void *>(&info)));

creationDate = gcnew System::DateTime((long long)(info.ftCreationTime.dwLowDateTime) | ((long long)(info.ftCreationTime.dwHighDateTime) << 32));

Additional volume information:

    wchar_t volumeName[1024];     wchar_t fsName[1024];     DWORD vsn;     DWORD fsflags;     BOOL ok(GetVolumeInformationW(path.c_str(),         volumeName, 1024,         &vsn,         nullptr,         &fsflags,         fsName, 1024));

and

    ULARGE_INTEGER free;     ULARGE_INTEGER total;     ULARGE_INTEGER totalfree;     BOOL ok(GetDiskFreeSpaceExW(path.c_str(), &free, &total, &totalfree));

and basic info

FILE_BASIC_INFO info;
BOOL ok(GetFileInformationByHandleEx(handle, FileBasicInfo, static_cast(&info), sizeof(info)));

Started adding mongodb support to C# code

I started adding in concrete MongoDB support to the tool code I’m building. Last night I incorporated the drivers into the solution and set up the connection code for the database. My initial attempt to directly use the C++/CLI object to push a record into the database failed but I expect to add a class that is properly serializable to BSON tonight and get volume information persistence working. I still need to get a better handle on updates in MongoDB. I know there are various sorts of atomic test and set sorts of operations on documents and in order to make this work properly with concurrent access, I need to understand those operations and use them to ensure that updates don’t ‘walk’ on themselves.

When I have a bit more time to type, I’ll add in more details on the MongoDB driver work and the approaches I’m using.