Al's Game Programming Blog

I have just about reached the limits of what I can hope to achieve with my C# to C++ translator project. There is so much more I would like to do but it is getting to the stage where I cannot make significant progress in weekend time alone. I'm also extremely busy at work and have little energy left. Maybe I'll pick up where I left off in a few months.

I did pretty well in the time available I think. I can translate simple C# programs to C++. The build process is well integrated into my IDE. I can do C# source level debugging using a standard C++ debugger. It took 6 days solid work to get this far.

This is a summary of what I have learned and what I think the benefits of C# would be in console game development. I'll probably round it off with a review of the disadvantages and the alternatives once my enthusiasm has had a change to die down a little!

Reflection

• Custom metadata annotations
• Can be queried at compile time for automatic code generation or at runtime
• Supports automatic serialization and deserialization
• Class factories
• Can be used to eliminate redundant code, e.g. visitor pattern or prototype pattern
• Automatic file format / schema generation
• Automatic binding of game code to tools such as RDBMS or level editor
• Automatic binding of game code to scripting languages such as Lua
• Automatic generation of multiplayer network protocol

Faster build times

• Game code can be run, tested and debugged on a .NET virtual machine for full rebuild times probably less than 1 minute
• Generated C++ code has minimal physical dependencies and automatically applies the pimpl idiom without programmer intervention

Reuse existing C# and C++ development tools

• Visual Studio 2005 would be a suitable IDE
• It provides basic editing like syntax highlighting, error checking as you type and code navigation
• Integrate into IDE using custom build rules, NAnt or Jam
• Automatic refactoring tools for rename, extract method, encapsulate field, etc
• C# source level debugging with any C++ debugger on any platform
• Profile C# program with any C++ profiler on any platform
• C# programs can be disassembled to native assembly language for optimization purposes

Testing and test driven development

• C# unit testing tools have a slightly more concise syntax than those of C++
• Support for automatically generated mock objects
• Automatic code coverage analysis

Fast, safe and fully automatic memory management

• Corrects flaws in reference counting by means of weak references and compile time analysis
• Memory leaks (unreachable allocations) are impossible
• Dangling pointers are impossible
• Better performance than garbage collection but not as flexible
• Reference counting constraints will not prevent the program from running in a garbage collected VM

Comprehensive class library

• Modify key classes in the Mono class library to work with reference counting
• Unrestrictive MIT license
• Easier to use than STL and boost (IMHO)

Compiled code should have similar performance to C++

• There is no reason to expect worse performance for constructs that have a direct equivalent in C++. They will be translated into exactly their C++ equivalents.
• Some constructs are higher level than C++, e.g. arrays are always variable length. Expect poorer performance in these cases.
• Expect improved performance for some constructs. For example, C#'s simplified inheritance model can support more efficient reference conversions. This is essential for effective use of interfaces.

Higher level language features

• First class language support for the observer pattern through events and delegates
• First class language support for thread synchronization constructs
• Support for interfaces
• Memory leaks and dangling pointers are impossible
• Runtime checking on array bounds, null dereference, arithmetic overflow
• These can be disabled in optimized builds
• Generics are an alternative to templates. There are pros and cons. Templates support meta-programming / generics reduce code bloat

Automatic code generation framework

• Compiler plugins generates code from C# metadata at build time
• Serialization
• Bindings
• Diagnostic stack traces
• Remote procedure call
• Other schema languages / DDLs

C++ / C# interoperation

• Methods can be implemented in C++ by using the "extern" qualifier
• Classes can be defined in C# so that their metadata is reflected but then actually implemented in C++
• C++ can call C# methods directly and access C# fields and properties directly because they are translated into C++

Miscellaneous

• C# game code can be reused directly in a C# tool, such as a level editor
• Translator could actually translate any .NET language to C++, e.g. F#, VB.NET or even Managed C++ or C++/CLI

# posted by Alastair Patrick : 4:41 PM