[XMark]

I've jumped back into work on the ARC Legacy Gold engine, and currently I'm trying to get collision detection to work. The way I'm doing it is over the 128x128 map is another map which shows where you can walk and where you can't. I figured the best way to do it is for only 1 bit of data to be used for each tile (0 = not wall, 1 = wall) but there doesn't seem to be a binary data type in C++. I've googled bit manipulation and found some really confusing algorithms to isolate individual bits using bitwise AND and OR operations, but I was wondering, is there some kind of standard C or C++ library to hold a really big chunk of bits in an array-like structure?

EDIT:

Oh, also, my research led me to making a struct to hold variables in individual bits like
typedef struct {
unsigned char switch1:1;
unsigned char switch2:1;
} switches;

Is there anyway to make a switch array within the struct? (so I could access it like switches.switch[4] = 1)
Setting it like unsigned char switch[8]:1; doesn't seem to work.
_________________
Mark Hall
Abstract Productions
I PLAYS THE MUSIC THAT MAKES THE PEOPLES FALL DOWN!

[Rainer Deyke]

Since, using 'unsigned char', you're only looking at 16K, I'm not sure why you even care. However, the template class 'std::bitset' in the C++ standard library might be what you're looking for.

[XMark]

yeah, I know it's a bit overkill but I have a history of extremely poor and messy coding style which I'm trying to eradicate using any means possible :) Thanks for the pointer.

EDIT:

heh, on second thought, maybe I'll just stick with chars. There's some wasted memory space but it leaves it open in case I want to extend the collision detection to include different movement types (like going slow through a swamp or something)
_________________
Mark Hall
Abstract Productions
I PLAYS THE MUSIC THAT MAKES THE PEOPLES FALL DOWN!

[Mandrake]

boolean values are always a nicety, and a standard...not sure if they are only 1 bit apeice though.

[Bjorn]

Never, it wouldn't even be faster. The following piece of code:

printf("%d byte(s)", sizeof bool);

outputs:

1 byte(s)

[mandrakeooo]

well that's pointless. why the hell would a bool need to be a byte? seems like a lot of wasted space to me.

[Rainer Deyke]

'bool' must be at least one byte so that its address can be taken. (Pointers can only point to whole bytes.) Moreover, some compiler actually have 'sizeof(bool) > sizeof(char)'. They justify it by calling it a speed optimization.

[janus]

yeah, some compilers use unsigned ints for booleans. Visual Basic uses a signed integer. >:) It's actually quite useful in that case.

[DrunkenCoder]

Actually if you wan't the best of both worlds use vector<bool> whats confusing about it is that it's really not a vector of bools, every element takes only one bit but if you later decide that you need extra bits to carry extra information you just change from bool to char and voila 8x memusage but lot's of extra bits to put data in.

isn't STL a wonderful thing?
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If there's life after death there is no death, if there's no death we never live. | ENTP

[Hard Rock]

[Mandrake]

hmm, that vector bool thing is nifty....i'm loving STL more and more i learn about it...only wish MSVC++ was up to date on the STL standards....there is so much cool stuff you can't even dream of accessing in VC++...which sucks.

[janus]

VC7 is supposed to have excellent STL support.

[Mandrake]

right, but i don't have the money to cough up dough for VC 7 or .net dev studio or whatever that package is called now. Purely a GCC man as of late.

[white_door]

well I have MSVS .NET (that's version 7) and while it has support for most of STL, it doesn't cover everything. like using custom function objects for sorting .. and other stuff. And it doesn't have any of the sgi extentions to STL either.

the hash_map is really quite cool :p

[XMark]

Is anyone else getting a popup asking for username and password for fury.rpgsource.net when they view this thread?
_________________
Mark Hall
Abstract Productions
I PLAYS THE MUSIC THAT MAKES THE PEOPLES FALL DOWN!