eye of the beholder engine mechanic explanation

EYE OF THE BEHOLDER ENGINE MECHANIC EXPLANATIONTHE DUNGEON CRAWLER ENGINE.

PART 01 GOOD GAME PLAY FUNDAMENTALS.

Let’s say, this is the original interface of the game with players and the dungeon window.

But you don’t like this one and change it with this one, to make a different game.

Or you are a totally Eye of the Beholder Freak like me, and have a lot of fantasy and create this one.

You can also change and interface and the players faces, you will find a lots of faces in the internet. Generally , make a lots of changes create another game , a completely new.

You can put some compass with real motion, remember Lands of Lore. I don’t like the compass from Eye of the Beholder, create or find other compass from internet.

You are in the Dungeons and dragons Game RPG. Put some money system in your game. Gold coins, Silver coins and Copper coins. Make changes more than Lands of Lore. Put some markets in the game. Some Merchant in the woods.

In my lesson I will use this interface in the examples.

Put some spell system. Make your game intelligent for players. Make players find rune stones and compel the players to remember the rune sequence to cast the spells. Put some overland map in your game and some Automap.

In your dungeons create a lots of portals, more than Eye of the Beholder I, II, III, Lands of lore does not have wall portals.

Make your portals, activated with rune pressing sequence. If you make a wrong sequence summon some evil monster , or transfer your party in other place in the map. Put some vortex in the portal. REMEMBER STARGATE.

And your deep levels of your dungeons , make then dark and Use torch to see inside them.

Now all of them does not explain the Dungeon Crawler engine, gives an Idea how to create another Eye of the Beholder game. Graphics, sounds, music, spells, intro, cinematics, finale and game play will attract many players. Make your game Masterpiece, make the

EYE OF THE BEHOLDER IVI am creating the EYE OF THE BEHOLDER IV make the EYE OF THE BEHOLDER V … hehe :o)

PART 02 EXPLANATION OF THE GAME ENGINE – WALL SIDES

The party is moving in a map, a map with squares like chess. In to the original Eye of the Beholder(EOB) you are traveling through a grid of 30x30 squares. In your own game you can change the dimensions of your map, you can make 30x50 100x100 etc. I recommend to live the dimension equal 30x30 or 40x40 or 200x200.

In this article, there will b some technical language for programmers, like pseudo C++ code. I will explain how to make it a playable game.

When the game starts, computer makes some initializations in memory and prepares the position of players, (Position in the map in X,Y), status of the player (Health , experience, weapons etc) , put the party somewhere in the game in one floor (The level), initializes the direction, (North, south, east, west), put the monsters, prepares the graphics and begin the game.

All of these things are familiar to programmers as variables and groups of variables (Structs).

With this information you will receive, you will learn with approach, how to understand the engine core.

But you need some other libraries to make sounds, music, graphics and cinematics.If you have choose your language , I recommend c++ or c. And you choose your

graphics engine then start your core.Programming libraries are stucks of ready programmed functions, which help you to

make the boring parts of the game , like , draw the sprites, play the music, manage your keyboard and mouse events.

If you are programming with c++ , I recommend DEV C++ or Visual C++ 6.I recommend Allegro library for your , Sprite Drawing functions ,your music and

keyboard and mouse events. This library does almost everything you want to create very easy your desirable Eye of the Beholder, it has a lots of 2D function for your graphics.

The Eye of the Beholder engine is not 3D , is 2D only and is easy to create this kind of game.

Lets start explain thing and what happened, behind the scene. The space of the (Eob) are the levels , as a programmer I will say , I am in the big

skyscraper with a lots of floors Levels. If I want to say to the computer with c++ , create for me one big skyscraper with 100 floors I will say. Int Levels[100][30][30][4];

This means I said to my computer to create an array, a fourth dimensional table, but the game is neither 3D nor 4D why I am creating the fourth dimensional array?

Is my skyscraper 4D , like time traveling? No. No I will not create a sci-fi space game, but I need to explain to my computer that.

I want every floor of my game… Int Level[Number_of_Levels][x_size_in_squares][y_size_in_squares][four_sides];

This means, my capacity of my game is a big adventure with 100 levels , each level has 900 squares 30x30=900 , equal in size 30 horizontal , 30 vertical and four sides.

The fourth dimension is the direction of the wall, (North, South, East, West).Each square is a cube, a hollow cube, with four sides, each side has one wall.

I render the walls in 3D to understand how the engine works.

Each square is hollow, has 4 sides with walls. Each wall is a distinct element.In each side you can put different graphic. The render bellow figures in 3D how wall will

appear if you put other graphics in each side.

Here you see, one the left texture with Curtain and on the right neat wall.If you see the colors between the wall up and the wall down are different.With one word, you don’t need to play with color palette, to change dungeon. In the

original (EOB) engine, program plays with color palettes, when you are changing dungeon layout. In my engine all are in 16 bit colors so you don’t have to play with palettes when you change a dungeon. Look the example bellow. Mix of Dungeons with Azure Darkmoon walls.

Remember the Dungeon with some turtles and a labyrinth with some medusas. I hate this level.

In the figure you see azure level graphic wall, with deep dungeons together in one wall.

So now you can recognize this, there is no limit how many graphics you can put in only one level. You can make a grand mix of graphics from all (Eobs) and create a totally strange new level without need to play with palettes, because we don’t have 256 colors , we have 16 bit colors.

All of these squares if we put them in our floor side by side we will create this 3D figure. This is our map and this is the way that the Eye of the beholder engine makes corridors and dungeons. Look the figure and I will explain how the graphics appeared in the (EOB) engine.

If I cover then on the top, you will see a beautiful labyrinth with corridors.

Imagine my skyscraper, has 100 floors like this one, is a big chaos

All of them that I explained are in the way to understand how the wall appears with four sides, but when you play the game you are looking the graphics in front of your eye, like first person RPG. Lets Change Perspective view and now we will see the Dungeons, as we usually see them in the game play.

PART 03 – THE GAME ENGINE ON THE SCREEN OF THE PLAYER.

This is the interface of (EOB) This is my example in my engine.

The game action take place in a smaller window in the upper left corner on your screen. In (EOB) and on the upper right corner in Lands of Lore and in my example.

In this screen this Smaller window, are the eyes of the players. The first person.You are see the floor with marble tiles and the ceiling. This is your Back Drop.With this backdrop understand where are you, in the game, if you see marbles you

understand, you are in a temple, if you see old dark stones or rocks, you are in the caver or dungeon, if you are seeing other kind of backdrop for example if you are seeing flowers and trees, you understand you are in the woods. (Forest).

Here in the figure there are some kinds of backdrops.

But you can make some mix of them and create other ones.

When you play you see the backdrop of the dungeon you are.Now computer calculates the walls in front of you, when you are in the dungeon. There

are some images that put in front of backdrop, in special positions like a puzzle and creates the illusion of 3D perspective of dungeon crawler view. Every wall has a small sprite of its position if the wall is near or if the wall is far.

The walls put in front of the backdrop and covers the backdrop. The walls put in the hierarchical sequence, first put the far away walls, the nearer walls that covers the far away walls below, then put the near wall in front of the nearer walls and covers the nearer wall. And the left and right wall puts in front of the player square.

The normal walls hierarchy is these :First there are far-far side wall, are the smallest with the deepest color and are on far sides.

These tiles are 2 and is difficult to see with your eyes.Second the far away walls, are the smallest with deep dark color.

These tiles are 5.Then there are far away side walls, are small but little bigger than the far-far away wall.

These tiles are 4.Then there are nearer wall, little bigger than the side wall, and its color is little whiter.

These tiles are 3.Then there are nearer side walls are bigger than the previews wall to cover then in front and are more whiter in color.

These tiles are 2.

Then there the walls in front of player.

These tiles are 3At the position of the player there are visible only the left and right walls.Are the biggest of the kind.

These tiles are 2.The font and the side wall in front of player and in the sides of the players are the biggest

and most beautiful graphics of the game, because are very-very close and are big and clear. And you can play with them better. In this part all game takes the action, because in this distance you are able to pull levers, push button, pull ropes, activate key locks, open doors, put items on wall niches, windows, and any kind of decoration, can be visible and very clear.

Some very beautiful walls in front of the player.A beautiful tapestry with element of air.

A beautiful sign on the wall, to read and take information about some warning or some riddle.

Also make it gold in upper left. If you are in a palace.A beautiful window in the nigh or in the day.

Window, with wall mix.A beautiful frozen key lock

A beautiful new graphic mix. A window with good rotten key lock.

or you will need 3 keys to unlock one door.So you can imagine, there is no limit in your fantasy.

Now its time to say something technical.When the game starts, computer initialize a group of variables in about your player. The group is assigned as struct in C++ language. If I want to say I have my party I need to say to the computer.

struct Party { int party_pos[100][30][30][4]; int direction; int x; int y; int player1_hp; int player2_hp; int player1_mp; int player2_mp; int armor_class;};

This is small code, I say to computer create one group of variables numerical and then initialize them.In this group, I say the party can be in my big map with floors.I define some direction.Some position in x,yAnd some characteristics for players as , hit points, mana points for mages, armor for fighter etc.

The next step is to load some map in memory and start fill the floors of my skyscraper with walls, doors traps, levers, but only as graphics. They will not work.If you want to make them work, the mechanism is more complicated.

My map file could be a text file , or you can make it encrypted with a special algorithm to not be accessible by cheaters. Hmm this door is locked, lets remove the door from map file.No-no never. Stay and play.

Also you can put your map files in one zip file and lock the zip with password if don’t you want to make encryption algorithms,

The map file format in my engine is similar to the original, the original , is in binary format, mine is in special text format.

Each square has four sides for each wall direction. If I want to create horizontal 30 squares I make this.

Each 00 is the palette of wall from 00 to 99 different kind of walls, lock, levers, stairs etc.The _ character is the mark of my program to know if the square is end and lets go to next square.

This example appears one simple map with 6x6 squares 36.The palette of :00 is an empty square – Means player pass through.01 is a solid wall with some marbles.02 is a solid wall in flip, about this I will explain later on with is flipped.03 is a illusion of solid wall, but this wall is fake, need special (True seeing spell to see it).04 is one window.05 blah blah…

01.01.01.01_04.01.01.01_01.01.01.01_01.01.01.01_01.01.01.01_01.01.01.01_00.00.00.0001.01.01.01_00.00.00.00_01.01.01.01_01.01.01.01_00.00.00.00_00.00.00.00_00.00.00.0001.01.01.01_00.00.00.00_00.00.00.00_00.00.00.00_00.00.00.00_00.00.00.00_01.01.01.0101.01.01.01_00.00.00.00_01.01.01.01_01.01.01.01_01.01.01.01_01.03.01.01_01.01.01.0101.01.01.01_00.00.00.00_01.01.01.01_01.01.01.01_00.00.00.00_00.00.00.00_00.00.00.0001.01.01.01_00.00.00.00_01.01.01.01_01.01.01.01_00.00.00.00_01.01.01.01_01.01.01.0101.01.01.01_00.00.00.00_01.01.01.01_01.01.01.01_00.00.00.00_01.01.01.01_01.01.01.01

With this map file you see some 01 and 00 that means there is a corridor which turns to the right and there is one window at the end of the corridor.The red color , the map file will be black and white there are no colors in map files.I made the 04 in red to explain. Why only the first is 04 and other three are 01?This means the wall which faces on the north will have one window texture and other sides will be only solid wall.I made the 03 in the map with blue.This means , in this square there will be an illusion wall that faces only on the south. So if the player passes the illusion square , there is no return, because the green 01 is the north solid wall and you can’t pass through a solid walls. So you are trapped and you are enter in other map which leads you perforce , to a corridor with a stairs which leads down to the other level with dungeon and very evil monsters.

So from this you can understand, when you create your map, you are create your own adventure.

Now I will explain how the graphics are appeared on the screen with this map.

This map load the level 20 on my big skyscraper.So if I want to say to my computer, that I am in the 20th floor I need to say with pseudo code, with my own created function.Loadmap(“c:\eob4\map20.maz”);

In the similar way, original (EOB) loads the .maz files in the memory and creates the illusion of wall an the levels.

But the real mechanic is more complicated.You need to make a loop to scan whole 6x6 squares.

First you need to say to your program in which level you are , to make a relation of the .maz file with the correct map.You can put some header strings before you start scanning your file and create your map.You can say to the program read first the header strings , what I mean.This file will not have only the wall, but will have and the info of the level.So you can read the square bracket bypass this and then read 5 ascii characters , I mean you pass the bracket then read the word “Level” so the program understand the next info are about map file. Then read the 20 with 2 ascii characters only and stores the string “20” in a variable.Active_Level=atoi(string(5,2)); this is a pseudo code. You will create a function that saysPass the first 5 characters and take the last 2, the only “20”. The atoi function is real in c++ , means alp arithmetic to integer. Convert one word in number. In my file the Word Level20 are without spaces so I need to take only the word Level and only the number 20.I keep the string “Level” and now I know this is about the level and I store the number 20 in one integer.

My map array I had said before is a fourth dimension table. Int Levels[100][30][30][4];

And put my active level in my skyscraper like this.

Levels[Active_level][30][30][4];

[Level20]01.01.01.01_04.01.01.01_01.01.01.01_01.01.01.01_01.01.01.01_01.01.01.01_00.00.00.0001.01.01.01_00.00.00.00_01.01.01.01_01.01.01.01_00.00.00.00_00.00.00.00_00.00.00.0001.01.01.01_00.00.00.00_00.00.00.00_00.00.00.00_00.00.00.00_00.00.00.00_01.01.01.0101.01.01.01_00.00.00.00_01.01.01.01_01.01.01.01_01.01.01.01_01.03.01.01_01.01.01.0101.01.01.01_00.00.00.00_01.01.01.01_01.01.01.01_00.00.00.00_00.00.00.00_00.00.00.0001.01.01.01_00.00.00.00_01.01.01.01_01.01.01.01_00.00.00.00_01.01.01.01_01.01.01.0101.01.01.01_00.00.00.00_01.01.01.01_01.01.01.01_00.00.00.00_01.01.01.01_01.01.01.01

Now I know that , this map will fill the 20th floor of my dungeons.Then I need 2 loops.For in c++ and other languages are very useful.

After that if I know , the info which will follow are about the wall. My code will be like this.For (map_x=1; map_x<=30; map_x++){ For (map_y=1; map_y<=30; map_y++) { read_wall(north); read_wall(south); read_wall(east); read_wall(weast);

Now I am reading the file with each wallsThen I call some function to bypass the “_” character

Levels[Active_level][map_x][map_y][read_wall];

Remember is a pseudo code.Looks like c++ but some functions need to be created by you.And I close the brackets. }}

Now the level 20 map filled.

Then now we need to check If we are facing in north. We had this struct in the program before.

struct Party { int party_pos[100][30][30][4]; int direction; int x; int y; int player1_hp; int player2_hp; int player1_mp; int player2_mp; int armor_class;};

if we need to put the player in the map.We need to say.

Party.x=2;Party,y=3;

And the party will stay at the yellow square.

Remember the file

[Level20]01.01.01.01_04.01.01.01_01.01.01.01_01.01.01.01_01.01.01.01_01.01.01.01_00.00.00.0001.01.01.01_00.00.00.00_01.01.01.01_01.01.01.01_00.00.00.00_00.00.00.00_00.00.00.0001.01.01.01_00.00.00.00_00.00.00.00_00.00.00.00_00.00.00.00_00.00.00.00_01.01.01.0101.01.01.01_00.00.00.00_01.01.01.01_01.01.01.01_01.01.01.01_01.03.01.01_01.01.01.0101.01.01.01_00.00.00.00_01.01.01.01_01.01.01.01_00.00.00.00_00.00.00.00_00.00.00.0001.01.01.01_00.00.00.00_01.01.01.01_01.01.01.01_00.00.00.00_01.01.01.01_01.01.01.0101.01.01.01_00.00.00.00_01.01.01.01_01.01.01.01_00.00.00.00_01.01.01.01_01.01.01.01

The player will see this on the screen.

This was a very good remix of walls and backdrop.

Why is this happened and how?

When the party is facing to the north and if there is a wall in front of players, you are checking if in on square in front of you there is a wall.

On the Map players are moving in x and y positionsIf you are facing to the north and you have a wall in front of you, check the party y position -1 on the map and the x position is the same.If I want to do this with code I will write this.

If (Levels[20][Party.x][Party.y-1][1]==04){//This is your function of printing sprites on the screendrawsprite(screenx,screeny,”Wall_texture”); }

If you want to check if there is a wall 2 squares far from player you need to check your party Y position – 2 you will write this code.With order first the far sprites and then the nearer sprites to cover each other.



The screenx and screeny variables are the variables in pixels to plot your sprite on the screen.

Let’s explain this better if you don’t understand.

In this figure we have the map as a grid. The blue square is the position of our part.The white lines on the grad are the visible walls in our eyes and these walls are drawing on the screen for now.The wall A is the left wall this wall appears in the party_x-1,party_yWe plot the sprite of Wall A 133 pixels horizontal and 7 pixels vertical to put correct on the screen and make the graphics good.

The code here could be

If (Levels[20][Party.x-1][Party.y-1][3]==01){//This is your function of printing sprites on the screendrawsprite(133,7,”Wall01a”); }

Now you are checking the next wall in front of you 2 squares in front and 1 square to the left.The sprite will plotted on the screen 158 pixels horizontal and 15 pixels vertical.The code will be like this.

If (Levels[20][Party.x-2][Party.y-1][3]==01){//This is your function of printing sprites on the screendrawsprite(158,15,”Wall01b”); }Now the next wall will be plotted on your screen but the code will change a little.

The code Levels[20][Party.x-2][Party.y-1][3] The “3” will change now.The new code will beIf (Levels[20][Party.x-3][Party.y][1]==04){//This is your function of printing sprites on the screendrawsprite(182,27,”Wall04c”); }This means in the fourth dimension the table Levels[First][Second][Third][Forth] is the direction of the wall.

In the map file I had this. 00.00.00.00_00.00.00.00_...The fourth dimension of my array when if is 1 means the wall face NorthThe fourth dimension of my array when if is 2 means the wall face SouthThe fourth dimension of my array when if is 3 means the wall face WestThe fourth dimension of my array when if is 4 means the wall face EastIn our example the Window square is 04.01.01.01 that means the wall that faces in North is 4

If (Levels[20][Party.x][Party.y-3][1]==04)We are on Level20If (Levels[20][Party.x][Party.y-3][1]==04)We are on square x position of our partyIf (Levels[20][Party.x][Party.y-3][1]==04)We are checking in 3 squares far in front of our party is somethingIf (Levels[20][Party.x][Party.y-3][1]==04)We are checking the North side of square for us.If (Levels[20][Party.x][Party.y-3][1]==04)We are checking the palette of the wall, no the color palette we check the kind of wall.

This is the only the one quarter of the wall engine.If you want to turn to the left right you are changing directionIf you where North and turn left, now you will facing to the WestIf you where South and turn Right, now you will facing to the East

The difficult part is only the North and West. The South and East are almost the same with negative sign.The North Code wasIf (Levels[20][Party.x][Party.y-3][1]==04) //Check for NorthNow will change a +3 andThe South code will be like this one.If (Levels[20][Party.x][Party.y+3][2]==04) //Check for SouthYou need to assign some direction flag with value from 1 – 4If (Direction_Flag==1) { then draw_walls_North(); }If (Direction_Flag==2) { then draw_walls_South(); }If (Direction_Flag==3) { then draw_walls_West(); }If (Direction_Flag==4) { then draw_walls_East(); }

And then use the code. Like a function

Draw_wall_West(){ If (Levels[20][Party.x-1][Party.y][3]==01) { //draw the sprite correct on my screen…. }}If you want to check the East wall , negative the singsDraw_wall_East(){ If (Levels[20][Party.x+1][Party.y][4]==01) { //draw the sprite correct on my screen…. }}

So you will have this on your screen.

This is the West wall not North wall.If you want to appear the East wall , just negative your sings.When I mean Negative I mean Reverse when some sing is “-“ minus turn it to the “+” PlusWhen a sing is “+” plus turn it to the minus “-“When turning your player check the last direction_flag variable. You can put the direction variable to your party group struct.Like this;

struct Party { int party_pos[100][30][30][4]; int direction; int x; int y; int player1_hp; int player2_hp; int player1_mp; int player2_mp; int armor_class; int direction_flag //This variable added now};

check: If you facing to the North.When you press 7 key to turning to the leftIf (Party.direction_lag==1) { Party.direction_flag=3; } //New Direction is WestWhen you press 9 key to turning to the rightIf (Party.direction_lag==1) { Party.direction_flag=4; } //New Direction is East

This was the Map Explanation only , how the graphics appear on the screen.I will post how the event are working with game , how to push buttons on the wall, how to open door and how to interactive change one wall in runtime. In other document

eye of the beholder engine mechanic explanation

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