Tag: game development

Weekly Round-up, March 16, 2024

John Winkelman

Looking East across the Grand River at the Sixth Street Bridge Dam, at sunrise.

[The photo this week was taken from the fish ladder on the west side of the Sixth Street Bridge dam, facing east into the sunrise.]

This past Sunday, feeling exhausted and also nostalgic, I dusted off an old Lenovo ThinkPad 11e, fixed some issues it had with continually dropping its internet connection, and turned it into my retro gaming machine. I have scores of games purchased over the years from GOG.com, so I installed a few of them – Hammerwatch, Ultima IV, and others.

One of my favorite games from back in the 1980s was Telengard, a sort of graphic roguelike which I played A LOT on my Commodore 64. There are a few ports and remakes available now, but while I found a few that could be played online, I didn’t find any which I could successfully install on the ThinkPad. No big deal; there are ways to get around this, including porting the Commodore BASIC source code to Javascript and having it run in the browser. It wouldn’t take long; anything that could run on a C64 is miniscule compared to even the most rudimentary of games available now.

But my research turned up one interesting bit of trivia: Back in 2005 someone released an updated version of Telengard, which I had downloaded and played once upon a time. That person was Travis Baldree, who wrote the absolutely wonderful book Legends and Lattes. Baldree is one of the developers of Torchlight, also one of my favorite games, and one which I played A LOT back around 2012 – 2015.

Reading

Loaded: A Disarming History of the Second Amendment, by Roxanne Dunbar-Ortiz. I picked this up in June 2018 at City Lights Bookstore, when my partner and I spent several days in San Francisco at the end of a two-week vacation that started with stops in Las Vegas and Phoenix.

Writing

Another week with little writing, though I do have a plan to start some deep worldbuilding for the rewrite of my 2022 NaNoWriMo project Cacophonous. Just too much noise in the world right now.

This Week’s Writing Prompt

Subject: Reincarnation, Fae
Setting: Frontier
Genre: Literary Fiction

Listening

John Zorn, Baphomet.

I’ve been a fan of John Zorn since I first heard his album The Gift while sitting in Common Ground Coffee House in the early 2000s. “Baphomet” is a single track and also an album, prog rock by way of avant-garde jazz, and a fantastic listen. I think the theme music for writing Cacophonous, when I finally get around to it, will be Zorn’s oeuvre, mixed and randomized and on heavy rotation.

Interesting Links

Yet Another New Old Project : Procedural Terrain

John Winkelman

[CLICK HERE to see the Procedural Terrain Explorer]

From 2004 to about 2009 I spent a lot of time playing around with procedural generation, generative art, and game design and development. Naturally at one point all of those interests came together and I began to research ways that game maps could be built using procedural generation techniques. I started several games but they never went beyond the planning or rudimentary prototype stage. I learned a lot about programming and wrote a lot of code, but never really had much to show for it.

In November 2007 I successfully created a 3D-ish height map using Perlin Noise as generated by the built-in Actionscript functionality. Since a grayscale image is made up of 256 possible colors, it is simple to interpret the values as heights. And with 256 values to choose from it is simple to come up with color substitutions so that instead of something which looks like clouds you have patterns which look like lakes, plains and mountains.

Now I have successfully recreated and expanded upon that experiment, using plain Javascript. Instead of Perlin Noise, this version uses Simplex Noise, though if I move toward turning this into a full game I will switch to OpenSimplex or something, because Perlin Noise and Simplex Noise are copyrighted.

With the basic generator in place you can add whatever colors you want, to make the height map look like whatever you want.

More blog posts and detailed instructions will follow, but for now head over to the labs and enjoy the experiment!

 

 

Procedural Generation X – User Modified Content

John Winkelman

Having all the content in a game created dynamically simplifies many aspects of game design. One code base can potentially create an infinite number of unique gaming experiences. However, what if you want to include a save game feature? If the game content is created anew every time the game is loaded, how is it possible to close the game, then pick it up tomorrow without losing all my progress?

Fortunately, the very act of creating locations and objects can be used to allow data to persist across multiple sessions. Here is an example:

Imagine you have created a dungeon crawl in a procedurally generated cave. The player has the option to dig through walls to reach e.g. deposits of minerals. You want to have a save-game feature, but you don’t want to have the caves reset to new every time the game is reloaded.

Every location in the cave has a unique x/y coordinate, starting at the upper left corner with (0,0) and ending at the lower right with (63,63). Each of these points is either a wall or a floor tile. Now here is the brain-twisty part: you don’t need to store the individual tiles of the original state. Every time the tile map is regenerated, it will be exactly the same. It doesn’t need to be stored.

Your character blows up a chunk of wall, say, at (20,20). Suddenly, the tile map has changed. It has history. It exists in a state different from the one which was produced by the algorithm which created it. Does that mean the entire map needs to be saved now? No! The only piece which needs to be saved is the piece which has changed. And this can be done by creating a data file which saves only the changed pieces of the map.

{
x:20,
y:20,
z:0
terrain:0
}

Reading the above data, we can see that the map coordinate 20,20 on level 0 should be to the terrain-type 0. So a workflow would look something like this:

  1. generate the initial map data
  2. look for a save game file
  3. iterate through the save game file and, where necessary, change the tiles.
  4. render the map to the screen

 

Mersenne Twister in Actionscript

John Winkelman

A few years ago I attempted to create a game for the GameDev.net Four Elements Contest. I had an idea that I wanted the game to be a cross between Nethack and Elite – and maybe a little Spore – which is to say, loads and loads of procedurally generated content. I never got past a very rough prototype of the world-building engine, but I learned a lot about procedural generation, and game development in general. Specifically, that it takes a lot more time than I generally have available.

One of the artifacts of this experiment was an extremely useful Mersenne Twister class, which I ported over from a C class I found on Wikipedia. A Mersenne Twister is a seeded pseudo-random number generator. In other words, for a given input n and a range r, it will return a random number between 0 (or whichever number you designate as the lower bound) and r, using n as the seed.

How is that useful? If you want to be able to, for instance, save a game which is based on random number-seeded procedural content, you want to be able to return the same seed every time. And if someone wants to start a new game, you want that seed to be different, but also repeatable. If you can’t reload a saved game and have it be based off the same random number as before, then loading a game would be no different from starting a new one.

Anyway. Here is the Actionscript 3 class:

/*
   A C-program for MT19937, with initialization improved 2002/1/26.
   Coded by Takuji Nishimura and Makoto Matsumoto.

   Before using, initialize the state by using init_genrand(seed)
   or init_by_array(init_key, key_length).

   Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura,
   All rights reserved.

   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions
   are met:

     1. Redistributions of source code must retain the above copyright
        notice, this list of conditions and the following disclaimer.

     2. Redistributions in binary form must reproduce the above copyright
        notice, this list of conditions and the following disclaimer in the
        documentation and/or other materials provided with the distribution.

     3. The names of its contributors may not be used to endorse or promote
        products derived from this software without specific prior written
        permission.

   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
   CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.


   Any feedback is very welcome.
   http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html
   email: m-mat @ math.sci.hiroshima-u.ac.jp (remove space)

     -------------------

     Converted to Actionscript 2005 by John Winkelman
     Feedback welcome at john.winkelman@gmail.com
*/


/* Period parameters */
package org.eccesignum.utilities {
    public class MersenneTwister {
        private var N:Number = 624;
        private var M:Number = 397;
        private var MATRIX_A:Number = 0x9908b0df;   /* constant vector a */
        private var UPPER_MASK:Number = 0x80000000; /* most significant w-r bits */
        private var LOWER_MASK:Number = 0x7fffffff; /* least significant r bits */

        private var mt:Array; /* the array for the state vector  */
        private var mti:Number;

        private var seed:Number;
        private var returnLength:Number;
        private var maxSize:Number;

        private var returnArray:Array;


        public function MersenneTwister():void {

        }

        public function twist($seed:Number,$returnLength:int,$maxSize:int):Array {    //    seed number, number of values to return ,max size of returned number
            seed = $seed;
            returnLength = $returnLength;
            maxSize = $maxSize;
            mt = [];

            returnArray = [];

            mti = N+1; /* mti==N+1 means mt[N] is not initialized */
            var i:int;
            //var initArray=(0x123, 0x234, 0x345, 0x456);    //2010.04.20    modiied to the below
            var initArray:Array = [0x123, 0x234, 0x345, 0x456];
            init_by_array(initArray,initArray.length);
            for (i=0; i<returnLength; i++) {
                returnArray[i] = genrand_int32()%maxSize;
            }
            //returnArray.sort(16);
            //trace(returnArray);
            /*
            trace("\n1000 outputs of genrand_real2()\n");
            for (i=0; i<returnLength; i++) {
              trace(" " + genrand_real2());
              if (i%5==4) trace("\n");
            }
            */
            return returnArray;

        }


        /* initializes mt[N] with a seed */
        private function init_genrand($seed:Number):void {
            mt[0]= $seed & 0xffffffff;
            for (mti=1; mti<N; mti++) {
                mt[mti] = (1812433253 * (mt[mti-1] ^ (mt[mti-1] >> 30)) + mti);
                mt[mti] &= 0xffffffff;
                /* for >32 bit machines */
            }
        }

        /* initialize by an array with array-length */
        /* init_key is the array for initializing keys */
        /* key_length is its length */
        /* slight change for C++, 2004/2/26 */
        //    void init_by_array(unsigned long init_key[], int key_length)

        private function init_by_array($seedArray:Array,$seedArrayLength:Number):void {
            var i:Number = 1;
            var j:Number = 0;
            init_genrand(seed);
            //init_genrand(19650218);
            var k:Number = (N>$seedArrayLength) ? N : $seedArrayLength;
            for (k; k>0; k--) {
                mt[i] = (mt[i] ^ ((mt[i-1] ^ (mt[i-1] >> 30)) * 1664525)) + $seedArray[j] + j; /* non linear */
                mt[i] &= 0xffffffff; /* for WORDSIZE > 32 machines */
                i++;
                j++;
                if (i >= N) {
                    mt[0] = mt[N-1];
                    i=1;
                }
                if (j >= $seedArrayLength) j=0;
            }
            for (k = N-1; k; k--) {
                mt[i] = (mt[i] ^ ((mt[i-1] ^ (mt[i-1] >> 30)) * 1566083941)) - i; /* non linear */
                mt[i] &= 0xffffffff; /* for WORDSIZE > 32 machines */
                i++;
                if (i>=N) {
                    mt[0] = mt[N-1];
                    i=1;
                }
            }

            mt[0] = 0x80000000; /* MSB is 1; assuring non-zero initial array */
        }

        /* generates a random number on [0,0xffffffff]-interval */
        private function genrand_int32():Number    {
            var y:Number;
            var mag01:Array=[0x0, MATRIX_A];
            /* mag01[x] = x * MATRIX_A  for x=0,1 */

            if (mti >= N) { /* generate N words at one time */
                var kk:Number;

                if (mti == N+1)   /* if init_genrand() has not been called, */
                    init_genrand(5489); /* a default initial seed is used */

                for (kk=0;kk<N-M;kk++) {
                    y = (mt[kk]&UPPER_MASK)|(mt[kk+1]&LOWER_MASK);
                    mt[kk] = mt[kk+M] ^ (y >> 1) ^ mag01[y & 0x1];
                }
                for (;kk<N-1;kk++) {
                    y = (mt[kk]&UPPER_MASK)|(mt[kk+1]&LOWER_MASK);
                    mt[kk] = mt[kk+(M-N)] ^ (y >> 1) ^ mag01[y & 0x1];
                }
                y = (mt[N-1]&UPPER_MASK)|(mt[0]&LOWER_MASK);
                mt[N-1] = mt[M-1] ^ (y >> 1) ^ mag01[y & 0x1];

                mti = 0;
            }

            y = mt[mti++];

            /* Tempering */
            y ^= (y >> 11);
            y ^= (y << 7) & 0x9d2c5680;
            y ^= (y << 15) & 0xefc60000;
            y ^= (y >> 18);

            return y;
        }

        /* generates a random number on [0,0x7fffffff]-interval */
        private function genrand_int31():Number    {
            return (genrand_int32()>>1);
        }

        /* generates a random number on [0,1]-real-interval */
        private function genrand_real1():Number    {
            return genrand_int32()*(1.0/4294967295.0);
            /* divided by 2^32-1 */
        }

        /* generates a random number on [0,1)-real-interval */
        private function genrand_real2():Number {
            return genrand_int32()*(1.0/4294967296.0);
            /* divided by 2^32 */
        }

        /* generates a random number on (0,1)-real-interval */
        private function genrand_real3():Number    {
            return ((genrand_int32()) + 0.5)*(1.0/4294967296.0);
            /* divided by 2^32 */
        }

        /* generates a random number on [0,1) with 53-bit resolution*/
        private function genrand_res53():Number    {
            var a:Number = genrand_int32()>>5;
            var b:Number = genrand_int32()>>6;
            return(a*67108864.0+b)*(1.0/9007199254740992.0);
        }
        /* These real versions are due to Isaku Wada, 2002/01/09 added */
    }
}

And it is called like this:

var twister:MersenneTwister = new MersenneTwister();
twister.twist(17436,100,50000); // seed number, number of values to return, maximum size of a given value

Since I wrote this, many other people have made versions in Actionscript. There is a comprehensive list on the Mersenne Twister page at Wikipedia.

Procedurally Generated Map With Shading

John Winkelman

Procedurally-generated map

Click here to load the map. Once it launches, click the movie to activate it, then use the arrow keys to move around. Clicking “reset” will create a new map.

This is a quick update to the tile game experiments of days past. I worked up a better color palette, and figured out a way to include shading to provide a better sense of depth and scale.