csnorwood

csnorwood

1 2 3 12

Perfect Maze now working

After a thorough going over of the code, I’ve managed to get this one working. Although painfully slow, at least it works. In the future I will be looking at other algorithms which are much faster. I only remembered this one from a long time ago so I just thought I’d have a go on my own without any help with implementing it.

// File: generate.agc
// Created: 19-09-21

/*
	Attempting to generate a maze using a decent algorithm.
	Unfortunately this particular algorith is painfully slow,
	but for the time being, it does work.
*/

type MAZE
	seed as integer
	wid as integer
	hgt as integer
	maze as integer[0,0]
endtype

function maze_get_odd_random(max as integer)
	val = random(0, ((max - 2) / 2)) * 2 + 1
endfunction val

function maze_not_visited(obj ref as MAZE, xpos, ypos)
	val = obj.maze[ypos, xpos]
endfunction val

/*
	The width and height have to be even numbers.
	NB: In AGK this means 0 to width (as even) for example
		NOT 0 to width - 1
*/

function maze_gen(obj ref as MAZE, wid as integer, hgt as integer, seed as integer)
	obj.seed = seed
	
	SetRandomSeed(seed)
	
	obj.wid = wid
	obj.hgt = hgt

	/*
		Wierd way of assigning a multidimensional array
		Assign the first dimensions length
		And then assign the length of each separate part
		ie.
		a[0].length = 5 (giving a[0,4])
		is not the same as
		a[1].length = 10 (which gives a[1,9])
		
		Also, AGK arrays end with the value assigned.
		ie. length is 10 so the array goes from 0 to 10
		instead of 0 to 9.
	*/
	
	obj.maze.length = hgt

	for c = 0 to hgt
		obj.maze[c].length = wid
		
		for x = 0 to wid
			obj.maze[c, x] = 1
		next
	next c
	
	/*
		If I remember correctly, I choose a random cell.
		But, it has to be, erm, ODD or EVEN???
		I will find out...
		
		It has to be odd.
	*/
	
	currentx = maze_get_odd_random(wid)
	currenty = maze_get_odd_random(hgt)
	
	// set position to 0
	
	obj.maze[currenty, currentx] = 0
	
	done = 0
	
	repeat
		
		// iterations to run through (might increase)
		for route = 0 to 63
			
			/*
				Basically direction is UP, DOWN, LEFT or RIGHT
			*/
			
			direction = random(0, 3)
			
			select direction
				case 0:
					if currenty - 2 > 0
						if maze_not_visited(obj, currentx, currenty - 2)
							obj.maze[currenty - 2, currentx] = 0 // clear path
							obj.maze[currenty - 1, currentx] = 0 // between
						endif
						dec currenty, 2
					endif
				endcase
				
				case 1:
					if currenty + 2 < hgt
						if maze_not_visited(obj, currentx, currenty + 2)
							obj.maze[currenty + 2, currentx] = 0
							obj.maze[currenty + 1, currentx] = 0
						endif
						inc currenty, 2
					endif
				endcase
				
				case 2:
					if currentx - 2 > 0
						if maze_not_visited(obj, currentx - 2, currenty)
							obj.maze[currenty, currentx - 2] = 0
							obj.maze[currenty, currentx - 1] = 0
						endif
						dec currentx, 2
					endif
				endcase
				
				case 3:
					if currentx + 2 < wid
						if maze_not_visited(obj, currentx + 2, currenty)
							obj.maze[currenty, currentx + 2] = 0
							obj.maze[currenty, currentx + 1] = 0
						endif
						inc currentx, 2
					endif
				endcase
			endselect
		next
		
		/*
			Print this mazes iteration (just for testing)
		*/
		
		Print( ScreenFPS() )
		maze_print(obj)
		print("Calculating...")
		sync()
		
		/*
			Check if maze is done (the silly bit)
		*/
		
		done = 0
		
		for h = 1 to hgt - 1 step 2
			for w = 1 to wid - 1 step 2
				if obj.maze[h, w] = 1
					done = 1
					exit // quick exit if not done
				endif
			next
			if done = 1 then exit
		next
		
	until done = 0
	
endfunction obj

function maze_print(obj ref as MAZE)
	print (obj.wid)
	print (obj.hgt)
	//print (random(0, 2) - 1) // HUH
	
	for h = 0 to obj.hgt
		s as string = ""
		for w = 0 to obj.wid
			if obj.maze[h, w] = 1 then s = s + "#" else s = s + " "
		next
		print (s)
	next
endfunction

Hmm… Almost…

// File: generate.agc
// Created: 19-09-21

/*
	Attempting to generate a maze using a decent algorithm
*/

type MAZE
	seed as integer
	wid as integer
	hgt as integer
	maze as integer[0,0]
endtype

function maze_get_odd_random(max as integer)
	val = random(0, max / 2) + 1
endfunction val

function maze_not_visited(obj as MAZE, xpos, ypos)
	val = obj.maze[ypos, xpos]
endfunction val

/*
	The width and height have to be even numbers.
	NB: In AGK this means 0 to width (as even) for example
		NOT 0 to width - 1
*/

function maze_gen(obj ref as MAZE, wid as integer, hgt as integer, seed as integer)
	obj.seed = seed
	
	//SetRandomSeed(seed)
	
	obj.wid = wid
	obj.hgt = hgt

	/*
		Wierd way of assigning a multidimensional array
		Assign the first dimensions length
		And then assign the length of each separate part
		ie.
		a[0].length = 5 (giving a[0,4])
		is not the same as
		a[1].length = 10 (which gives a[1,9])
		
		Also, AGK arrays end with the value assigned.
		ie. length is 10 so the array goes from 0 to 10
		instead of 0 to 9.
	*/
	
	obj.maze.length = hgt

	for c = 0 to hgt
		obj.maze[c].length = wid
		
		for x = 0 to wid
			obj.maze[c, x] = 1
		next
	next c
	
	/*
		If I remember correctly, I choose a random cell.
		But, it has to be, erm, ODD or EVEN???
		I will find out...
		
		It has to be odd.
	*/
	
	currentx = maze_get_odd_random(wid)
	currenty = maze_get_odd_random(hgt)
	
	// set position to 0
	
	obj.maze[currenty, currentx] = 0
	
	done = 0
	
	repeat
		
		// iterations to run through (might increase)
		for route = 0 to 3
			
			/*
				Basically direction is UP, DOWN, LEFT or RIGHT
			*/
			
			direction = random(0, 3)
			
			select direction
				case 0:
					if maze_not_visited(obj, currentx, currenty - 2) and currenty - 2 > 0
						obj.maze[currenty - 2, currentx] = 0 // clear path
						obj.maze[currenty - 1, currentx] = 0 // between
						currenty = currenty - 2
					endif
				endcase
				
				case 1:
					if maze_not_visited(obj, currentx, currenty + 2) and currenty +2 < hgt
						obj.maze[currenty + 2, currentx] = 0
						obj.maze[currenty + 1, currentx] = 0
						currenty = currenty + 2
					endif
				endcase
				
				case 2:
					if maze_not_visited(obj, currentx - 2, currenty) and currentx - 2 > 0
						obj.maze[currenty - 2, currentx] = 0
						obj.maze[currenty - 1, currentx] = 0
						currentx = currentx - 2
					endif
				endcase
				
				case 3:
					if maze_not_visited(obj, currentx + 2, currenty) and currentx + 2 < wid
						obj.maze[currenty, currentx + 2] = 0
						obj.maze[currenty, currentx + 1] = 0
						currentx = currentx + 2
					endif
				endcase
			endselect
		next
		
		/*
			Check if maze is done (the silly bit)
		*/
		
		for h = 1 to hgt - 1 step 2
			for w = 1 to wid - 1 step 2
				if obj.maze[h, w] = 1
					done = 1
					exit // quick exit if not done
				endif
			next
			if done = 1 then exit
		next
		
	until done = 0
	
endfunction obj

function maze_print(obj ref as MAZE)
	print (obj.wid)
	print (obj.hgt)
	print (random(0, 2) - 1) // HUH
	
	for h = 0 to obj.hgt
		s as string = ""
		for w = 0 to obj.wid
			if obj.maze[h, w] = 1 then s = s + "#" else s = s + " "
		next
		print (s)
	next
endfunction

Not quite working… Need a nap… Not well…

A Perfect Maze

So I got an algorithm done last week that produced a perfect maze. Unfortunately though, I wiped my 2 x 1Tb SSD’s on my PC and didn’t back up the code.

So I am starting again.

(I’m not too good by the way, so I am documenting this)

I didn’t want a recursive algorithm because I think that on low end architecture this would be bad for memory usage. This meant that the algorithm would possibly be slower. For a 40 by 40 maze it would still be instant, even though there was a silly check in there.

Here goes. (back soon with some snippets)

I’m using AGK and will port everything to C.

Back to these C++ tuples

Okay, now that Christmas and New Year is finally over and I’ve got pockets like a white eared elephant, I decided to have another blast at these tuple things because they were doing my head in.

All along I’ve been thinking that a class/struct would be much better. In most cases I would be right, but then I thought, “Hang on, this is C++. Let me check if I can return a tuple from a function.”

Hey, turns out I could.

#include <cstdlib>
#include <iostream>
#include <tuple>

using namespace std;

auto get_tuple(string name) {
    return make_tuple(name, 1);
}

int main(int argc, char** argv) {
    auto t3 = get_tuple("FOO");
    auto t4 = get_tuple("BAR");
    
    cout << get<0>(t3) << endl << get<0>(t4) << endl;
    
    return 0;
}

And voila, just like that I can now return multiple values from a function.

The one thing you have to be careful of is the setup. A typo mistake or a type mistake can and will cost hours of debugging so be wary of things like this:

    auto t1 = std::make_tuple("foo", 1, 2);
    auto t2 = std::make_tuple("bar", 1.0, 2);

Now even if I added to the first tuple “foo”, 1f, 2, this would not match the second as the second tuple uses a double value. A pain for debugging.

Just the fact you can return multiple values of data without having to define a complete struct or class is actually quite a nice addition.

I have done some research into tuples now and found that these use cases are good, but for larger data, it is so much better even to still use a struct/class because with the above examples you still are having to use index values to access the data items. Where as a struct/class, the data items are named.

Although this however can be overcome by using enums, larger tuples are very likely better off being converted to a struct/class.

Even after 35+ years of programming I’m still learning.

Time to move onto something else… Bigger…

Some C++ tests

Well, after a while of faffing about with other things, I thought I’d go through some of the new features of C++17 and just a quick play about I found some very interesting new features.

#include <cstdlib>
#include <iostream>
#include <string>
#include <vector>
#include <tuple>

using namespace std;

int main(int argc, char** argv) {
    vector<string> strings = {
        "Hello",
        "World",
        "This",
        "is",
        "the",
        "best",
        "I",
        "can",
        "do"
    };
    
    for (string str: strings) { // I now know
        cout << str << endl;
    }
    
    cout << strings.size() << endl;
    
    // https://www.geeksforgeeks.org/tuples-in-c/
    // makes it more interesting with tuple_cat
    
    auto mytuple1 = make_tuple("triangle1", 't', 10, 15, 20); // interesting...
    auto mytuple2 = make_tuple("triangle2", 'b', 1, 2, 3);
    cout << get<0>(mytuple1) << endl;
    mytuple1.swap(mytuple2);
    cout << get<0>(mytuple1) << endl;
    cout << tuple_size<decltype(mytuple1)>::value << endl;

    return 0;
}

First off the std<vector> initialisation can now be done as it is with Java, but more interestingly is the for loop which works with any class list. That makes life so much easier for C++ handling data.

The next bit was the tuples. For some reason I always associated tuples with a set of 3 items. But after this… This allows for a quick, and maybe dirty way, of avoiding setting up a new class to handle short bursts of data. Very simple.

Now I’m going to play around with some more C++17 features. I may end up moving completely back to C++ and away from Java again.

EDIT:

The output:

Hello
World
This
is
the
best
I
can
do
9
triangle1
triangle2
5

RUN FINISHED; exit value 0; real time: 0ms; user: 0ms; system: 0ms

Java ‘long’ to C++ ‘int64_t’

Hallelujah!

For the last two weeks I’ve had an intermittent problem with my C++ version of the crypto socket client, and tonight I finally cracked the issue.

The Java version is using ‘long’ for doing it’s calculations and the C++ version was using a 64 bit integer, which should have been fine until tonight I realised that Java was using its ‘long’ values as signed. Whereas I had been using ‘uint64_t’ in the C++ version.

This caused the C++ version to work once in every 5 to 10 tries. Just by removing the unsigned, it now works flawlessly.

Phew! Now I can blitz the rest…

(Yep, it has been a while since the last post)

csnorwood.com

It was tough to accept the change from my old website (wlgfx) to this new one (csnorwood), but I couldn’t ignore the benefits.

Yes, this is going to affect the search engines for some time but I’m used to that. I can still slowly build stuff in the meantime while the web crawlers do there stuff.

It’s highly unlikely that the the old web address is even going to link back to this new one, but what the hell. Time to move onward and upwards.

Rewrite from Java to C++

Okay, so my server is currently running on Java and makes use of DataOutputStream and DataInputStream. And whilst I’m on a rewrite, I need to wrap those into C++.

Which I thought might be a tad difficult…

It turns out that Linux automatically handles UTF-8 strings out of the box, so sending and receiving string is of no consequence. Which was one of my main worries before I looked into everything else which slowed down the transition. Java’s DataOutputStream writes it UTF-16 strings as UTF-8 strings over the wire. That’s that problem solved.

The other problem was wrapping the socket connection. Sorted. Easily done by returning the error status on every call and handling the active status of the socket.

The last problem was wrapping the Java functions for sending a Long, Int, Byte, String, etc… These need to be in network byte order, which is not little endian. I’m just going through that now.

Oh yeah, encryption using a Cryptographic Secure Pseudo Random Number Generator. Done and implemented to match perfectly the Java version… For now.

So hopefully soon, I’ll be able to test run this wrapper ready for a production run.

Amazing feeling

“I feel almost like a god!”

To have my own software running in the cloud and being able to serve its purpose, ‘feels good’.

Yes, I’ve had one of those moments of personal successful achievements accomplished.

Or something like that.

1 2 3 12