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The Vectrex Game

Dark Tower



Introduction

Like the Fortress of Narzod, the source code for Dark Tower was broken into several files to compartmentalize the code and make it easier to edit. The top-most file (the one that was submitted to the assembler) was DRKTWR.ASM and in-turn it would would link to the associated files.

The top most file for Dark Tower:

DRKTWR.ASM

The associated files:

BRGAND.DRK FRGMNTE.DRK MAP.DRK TOWER.DRK
COLIDE.DRK GOBLIN.DRK PACKS.DRK WARIOR.DRK
FIGHT.DRK GRDSCN.DRK SCENRY.DRK WIZARD.DRK
FLAMER.DRK INVENT.DRK SOUND.DRK  
FOREST.DRK MAGIC.DRK SUBR.DRK  

Just a comment:

  • I wrote the following Dark Tower description for Lee Chaden.

Game Description

Object of Game

Ultimately the player is required to unlock the door of the Dark Tower by solving the Riddle of the Keys. To solve the Riddle, the player must find four different keys that are scattered about the forest (or by bribing the Magician) and once in the player's possesion, the Dark Tower must be found (located at the centre of the map).

The keys are Gold, Silver, Bronze and Brass (one other treasure is to be found - the Crystal Crown).

Start of Game

After selecting the desired game option, the player's warrior appears at a random position within the forest. The warrior will not appear in the Zone of Death or near the map boundaries.

The player starts each game (independent of game option) with 2 bags of gold and 5 replacement warriors (6 total).

Options

1 = Player starts with no keys

2 = Player starts with the silver key only

3 = Player starts with the silver and bronze keys

4 = Player starts with the silver, bronze and brass keys

When selecting options 2 - 4, the player does not receive points for those keys initially given.

Forest Sequence

Forest Map and Boundaries

The forest is derived from a fixed map (the map does not change from one game to another). The map is laid out as 4 sectors, each containing 32 x 32 grid points (nodes). A node may appear as an object (ie - trees or boxes) or as a game play trigger (ie - scenery fog or plague). Any given sector can be identified by its characteristic tree type (the tree types are: elm, pine, lolli-pop and dead trees).

Note: other types of trees can be inserted within a sector without changing the characteristic tree.

There are a total of 4,096 objects on the map (64 x 64 nodes) consisting of the following break-down -

 
Total
Dead
Forest

Pine

Elm

Pop

Mixed
 
Brigand boxes   =   26 4 7 6 9 0
Magician boxes   =   17 4 5 2 4 2
Plague boxes   =   5 2 0 2 1 0
Fog boxes   =   5 2 0 1 2 0
Plague triggers   =   12 7 0 2 1 2
Fog triggers   =   5 0 2 2 1 0
Do-Nothing boxes   =   21 4 5 6 4 2
Treasure boxes   =   10 1 4 2 2 1
Scenery Keys   =   4 1 1 1 1 0
Scenery Gold   =   38 9 4 12 11 2
Dark Forest   =   4 2 0 0 1 1

Since the forest map is finite, something had to be done to define the boundaries of the map. Using a fog to define the boundary, the player may not leave the map without first being thrown back into the map (randomly). The boundary fog differs from the scenery fog in the following ways:

1. The boundary fog occurs even if the player holds a scout (and the boundary fog does not affect the use-counter of the scout).

Approaching a border is best indicated by the lack of any trees or objects (this appears the same as entering the Dark Forest).

Zone of Death

One entire sector of the map has been set aside for a Zone of Death. This area is apparent because of the dead trees. In the Zone of Death lies several of the treasure and magician boxes.

Within the Zone of Death, the plague (scenery or box) occurs with great frequency - therefore, it is only safe to enter the zone with a healer in possesion.

One game play function of the Zone of Death is that it increases the hazard associated with the fog (scenery or box). During a fog cycle, the player has a 25% chance of appearing within the Zone and if not prepared, can lose the game by plague alone.

Dark Forest

The Dark Forest is a zone where no trees or objects exist. There are several of these zones within in the map. In the largest such zone (located at the centre of the map), hides the Dark Tower. If not careful, the player can be lost in these zones. Because the zone looks like the border, entering one of these zones can be quite exciting for the player who has not learned the ins and outs of the map (because they may be entering a border fog).

Warrior

While in the forest sequence, a pedometer is displayed at the top of the screen. This pedometer indicates the number of steps since the warrior made his last turn. Direction of motion is also indicated (N, NW, W, SW, S, SE, E, NE).

Under some set of conditions, the warrior may not move. They are -

1. If the warrior is being drawn into or returning from a box or while the box is cycling.

2. If the warrior has been killed and awaiting replacement.

3. During the Magician sequence.

4. During the Brigand sequence, the warrior must stop motion to throw a flamoid.

Healer

The healer prevents the fatal effects of the plague (scenery or box).

A healer is available only from the magician (given enough gold).

A healer can be used only 4 - 6 times and is then lost. It may be regained from a magician again if the player has not used all the magician boxes and has sufficient gold.

Scout

The scout prevents the player from becoming lost during a fog (scenery or box). A boundary fog is not prevented by the scout, the player is lost if trying to cross the border.

A scout is available only from the magician (given enough gold).

A scout can be used only 4 - 6 times and is then lost. It may be regained from a magician again if the player has not used all the magician boxes and has sufficient gold.

Scenery Fog

Scenery fog is implemented as a mapped game trigger, with no warning (it does appear as a missing tree, but no one is likely to notice).

When the scenery fog is triggered, the fog ramps up from the bottom of the screen; the warrior and background are ramped down in intensity. At that time, a new position on the map is calculated and the process is reversed so that the player can see his new position within the forest.

Scenery Plague

Scenery plague is implemented as a mapped game trigger, with no warning (same as the scenery fog).

When the scenery plague is triggered, the plague ramps up from the bottom of screen; the warrior breaks up and ramps down in intensity until it becomes invisible (a dead player and a replacement is requested).

Following a scenery plague, subsequent encounters with the scenery plague trigger are inhibited for 25 seconds. This prevents a lost player from stumbling directly into a scenery plague almost immediately following the previous plague (but this does not prevent the player from finding a box plague and suffering its full effects). The scenery plague is also inhibited for the first 25 seconds of the game (so that the player does not get hit at the very beginning of the game).

General Box Behavior

The player must place the box immediately before the warrior on the screen before it can be opened. Pressing button #4 causes the box to start opening (pressing this button a second time closes the box, so long as the box has not opened completely). The box cannot be opened if the plague or fog is cycling or if a tune is pending.

While a box is cycling, the warrior cannot move.

All boxes appear alike, there is no clue toward the box contents. Since the boxes are determined by the map, it becomes very important that the player learns to map the forest and keeps track of his progress. This is the only way in which a player may avoid dangerous boxes.

Box Fog

When the box has fully opened, a fog cycle is initiated (similiar to the scenery fog).

Box Plague

When the box has fully opened, a plague cycle is initiated (similiar to the scenery plague).

The box plague is effected by the plague lock-out timer.

Do-Nothing Box

As the name implies, this type of box does nothing. It merely opens, pauses for a moment and then closes. I feel that it adds anticipation for the player.

Treasure Box

This box contains a no-risk treasure for the player and is very rare. The following treasures are possible for this box -

Bags of gold (1 - 9 bags, determined randomly)
        points = bags of gold x 100 pts.

Replacement Warriors (1 - 4 warriors, determined randomly)
        points = new warriors x 100 pts.

A treasure box can be opened only once per game, subsequent openings will take the player to the brigand sequence (once again, it is important for the player to learn how to map the forest).

Scenery Keys

In each sector of the map, lies one of the keys necessary to open the Dark Tower. As with all map objects, these keys are in the same position for each game. The key picked up is determined randomly at the time of the pick up and will vary from game to game.

After finding one of these keys, the player can pick up the key by walking toward the key. The player must walk directly to the key to pick it up (the player cannot back or turn into the key, but the key may be picked up during a fog or plague).

Any given key may be picked up once only once per game. If the key has already been picked up, it leaves a blank spot on the map that looks like a plague or fog trigger.

The actual number of scenery keys depend on the starting option, if the player has selected option #2 - then only three scenery keys are to be found in the forest.

Scenery Gold

After finding a bag of gold, the player can pick up the bag by walking toward it. The player must walk directly to the bag to pick it up (the player cannot back or turn into the gold, but the gold may be picked up during a fog or plague).

Any given bag of gold may be picked up once only per game. If the bag of gold has already been picked up, it leaves a blank spot on the map that looks like a plague or fog trigger.

Inventory Page

The inventory page reflects the status of player progress -

Player score

Number of replacement warriors

Amount of gold held

Treasures held

The inventory page can be requested at any time by depressing button #1. If a tune is pending, the inventory page is delayed until the tune is over.

Control Definitions

Joystick = Move warrior forward / backward or right / left

Button #1 = Inventory page

Button #2 = No defined function

Button #3 = No defined function

Button #4 = Opens the box (the box must be in front of the player)

Scoring

See treasure box description

Scenery Gold Key = 1000 pts.

Scenery Silver Key = 900 pts.

Scenery Bronze Key = 800 pts.

Scenery Brass Key = 700 pts.

Scenery Bag of Gold = 100 pts.

Brigand Sequence

The brigand sequence begins when the player opens a brigand box. The player is drawn into the box and must fight for the warrior survival. The player must destroy a randomly determined number of brigands (up to about 20 brigands). If the warrior is successful (kills all the brigands), then the player may receive a randomly selected treasure (see below).

If the warrior is killed, the player is returned to the forest outside of the brigand box. If the player is feeling brave, the brigand box may be attempted again. The player may enter the box as often as warriors are available.

Under certain conditions, the last brigand may flee the box instead of fighting. If this happens, the brigand sequence is still over. This should be a rare condition and represents a programming problem that could take a long time to fix.

The brigands throw most of the flamoids directly at the player, but some are thrown randomly (hoping that the warrior will move into them, while trying to evade the directed flamoids).

The warrior has an unlimited number of flamoids.

The warrior cannot be destroyed by his own flamoids. And the brigands cannot be killed by flamoids thrown by themselves or other brigands.

Control Definitions

Joystick = Moves warrior right or left only

Button #1 = Inventory page

Button #2 = Throw flamoid left

Button #3 = Throw flamoid straight

Button #4 = Throw flamoid right

Scoring

125 pts. for each brigand destroyed

Score depends upon treasure found

New warriors = number of warriors x 100 pts

Bags of Gold = number of bags x 100 pts

Be Gone = no points / no treasure

Magician Sequence

The magician sequence begins when the player opens a magician box. The player is drawn into the box and is open to the will of the magician. If the player has sufficent gold, a key or other treasure may be granted by the magician (the magician might just tell the warrior to bugger- off).

The amount of gold necessary is detailed below -

Gold Key   =   60 - 69 bags
Silver Key   =   50 - 59
Bronze Key   =   40 - 49
Brass Key   =   30 - 39
Crystal Crown   =   60 - 69
Healer   =   15 - 30
Scout   =   20 - 30
Warriors   =   10 - 20

A magician box can be opened only once per game, subsequent openings will take the player to the brigand sequence (the player must learn how to map the forest and keep track of which boxes have already been opened).

Control Definitions

Button #1 = Inventory page

Button #2 = No defined function

Button #3 = No defined function

Button #4 = No defined function

Scoring

Score depends upon the treasure granted

New warriors   =   number of warriors x 100 pts
Gold key   =   1000 pts
Silver key   =   900 pts
Bronze key   =   800 pts
Brass key   =   700 pts
Crystal Crown   =   1500 pts
Healer   =   300 pts (plus bonus warrior)
Scout   =   300 pts (plus bonus warrior)

Dark Tower / Riddle of the Keys

The Dark Tower is visible only when all four keys are in the possession of the player. The Dark Tower is located at the center of the map in the largest of the Dark Forests. This Dark Forest is surrounded by a forest of heavily mixed trees (all four tree types and trees alternate).

The Riddle of the Keys is entered by walking into the entrance of the Dark Tower (the Dark Tower may not be entered if a fog is pending, if the player is backing or turning into the tower). If the player does not answer the riddle correctly, the player is informed which of the guesses where correct and then is thrown back into the forest (the fog mechanism). If the player has a scout, then the warrior appears outside the Dark Tower for another chance (all the conditions for the scout still apply - it can only be used a limited number of times).

The combination for the Riddle of the Keys is determined randomly at the beginning of the game and does change for the duration of the game. Because of the way that the random number generator functions, certain combinations will occur more often than others and this bias will be machine dependent.

Control Definitions

Joystick = No defined function

Button #1 = Inventory page

Button #2 = Step to next key position (left to right)

Button #3 = Step to next key type (Gold, Silver, Bronze, Brass)

Button #4 = Test player defined key sequence against hidden key riddle

Scoring

3000 pts for correctly guessing the riddle.



 
 
 
 
 
 

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This page was last modified: 12 Jan 2017
By John Hall