Tuesday, May 28, 2013

My First Go at AI

The main driver my AI routines is the distance the player is from an enemy. The visible board size is 10 tiles now and the total map size will vary from level to level. A distance value of 4 is the starting point for the enemies to activate. It's an arbitrary value an will probably change in the near future after some play testing. The trick here is to balance the timing of the enemy movement with the player movement. Right now they all move at the same speed. See the video below.


This is my first attempt at tracking an object. There are some issues with the AI timer firing while the enemies have a target. For a first pass it is a good starting place.

Everything is going to be event driven. I have 2 timers now. One for the object movement, firing every 2 seconds, and the other one is for the AI to update the movement. Currently the AI has a nasty show stopping bug that I will need to address. When it fires the second time, after a distance check from the player, the Astar start and end values are getting set to nil somewhere. (Print statements here we come). I need to separate the enemy movement out of the object timer and make it independent. The choice I need to make is a hard one. Do I have every object have timed value and a running timer, or several timers at different intervals. I think the latter is less processor intensive and will allow swarms of enemies. A running timer would need to check every object every frame or have a way to register objects and their fire time. Time will tell.

Monday, May 27, 2013

The pathfinding bug is dead...Long live the pathfinding

For the last week I have been sick with a sinus infection and could not concentrate on programming, but yesterday I found the pathfinding bug. It is the small things kill you in programming. When I called the pathfinding method it worked with one object but when I used it on more than one object all hell broke out. Part of it was me and part of it was me and part of it was Codea's debug printouts. The error was with the object using the same path for everythinig. I first thought the list copy function was not working but I was using the same path for everything. A simple change from path = listCopy(path) to v.path = listCopy(path) fixed the error.

The only other bug related to movement is when he map is scrolled the pathfinding checks the wrong cordinates. That should be relatively easy to fix

Tuesday, May 21, 2013

Fighting a loosig battle with Codea Debugging

If you program for the Ipad with Codea then you are familiar with the print statement. The debug tools is a command line(a good start) and runtime errors that may or may not point to a relative piece of code. As a former Flash programmer I love the flexibility LUA has with data types and functions. I wish I was an uber programmer; to take advantage of coroutines and passing in functions as an argument would rock. But alas, this will not be. I guess the reason for this rant is I hate debugging. It's  probably a sign I'm a smart guy who can program, and not a programmer who is smart. Add in a time based play mechanic that can be real time or fire off timed intervals.

The mantra of every article I have read states, "Build a simple game first". I agree and all, but will I not follow that advice. If i am going to go through this grinder of a process then it had better be worth it.

On the programming front:
debugging the astar pathfinding return value are assigning wrong when called repeatedly.
The aster will not search the correct start and end values when the map is scrolled
Fixed various player movement issues with touch movement.
Decided to not add a mesh pool for dynamic enemy creation.
Enemy AI now knows when you are within 5ish squares of them and call a path to you. then start to move to your location. Still some major bug to squash. Arrrghhhh! So close

Monday, May 20, 2013

Realtime movement is a pain to keep track of

Today I was working AI of the enemies and I have several flags assigned to the player class. Every non-map object is a player and the tileType is keyed off to get see what tile it is. For example,

2 = Player
3 = enemy
4 = open
5 = Point of Interest
player = Player(id,tileType,isActive,target,path,pathCount)

The AI checks if the tileType is an enemy and then checks if the the distance to the player is <= the activation distance. The enemy then calls the astar to the position of the player and returns a list of coordinates. This path is assigned to the player.Path list and is updated every enemy clock cycle, currently 2 seconds(enemy speed). When the player/enemy moves path count is updated and the character moves closer to the target. When the target is reached the list is removed. A few bugs not withstanding it works. But when the player moves the enemy AI does not adjust to the new player location. I do not want the enemy to poll the player position every draw call and it would be good to update the pathfinding when an enemy is moved.

I will post a video when I get something working.

Saturday, May 18, 2013

Too 3D or Not to 3D

While reading a blog, project zomboid 's I think, there was a discussion on the amount of frames it would take to animate the characters. It was in the thousands. Not even possible on a Ipad. This thought arrived while programming the movement on the game. The current movement is tile based and the character moves the entire width of the tile. See the videos in previous posts. I think I want to have pre-rendered 3d characters, very low poly, and 5 frames of animations per character. It would not be wise to have your first project contain any 3D. Programming is hard and programming 3D, while possible, is harder out of the scope of this project.

I have not written about my background before. I studied fine art at Arizona State University, have programmed Flash professionally and was a professional comic book colorist.  Here is an old portfolio from 2006. http://www.freewebs.com/vidopiac/ My introduction to programming was a Pet CBM learning Fortran and Pascal in the mid 80's. I had a Mac 128 and an Amiga (awesome machine). On the 3D side I am a decent box modeler, and texture artist. I use Modo for 3D and on the 2D side I use Photoshop, Procreate, and Artrage. 

The 3D can be done me, time permitting. 

TO be contiued... Star Trek is calling me.... Phasers on Awesome

Thursday, May 16, 2013

More thoughts on movement

This post will be mainly be about player movement. Currently I have the player move when you press to select the player and drag your finger to where you want him to go. This works fine but it leaves your tacticle options at the mercy automatic pathfinding. To fix this I will add the ability to select,an empty tile next to the player, and draw your parth the  player will follow. The tiles will so show they are selected. so you can see the path. To stop the movement early tap the player to stop or maybe drag another path and clear out the old one. It should be easy to implement  and when I get home after work I will try it.

Monday, May 13, 2013

Movement is in with lots of things to fix

It is not as bad as it sounds. I have the Astar pathfinding working with the character and a flag goes off when ever the player walkes over a game object. The idea is every time the game clock fires the enemy will move. The enemies check a random direction to move one square and if that position is a walkable tile then the enemy moves. I need to also check the list of enemies to see they don't walk over themselves or other things that block movement. This is the starting state of an enemy and when they are activated then calculate the astar to the point of interest

I also need to start a thinking about the z sorting of the objects and get rid of some troublesome bugs.
Another video


I speed up the time so you can see them move in the green walkable areas

Food Will Have To Wait

While implementing the movement for the character I needed to decide what to do when the character moves over a tile that is not an enemy. Every game object is drawn above the map and when you walk over it I currently set the uv cordinates to a transparent and it dissappears without having to translate it or destroy it. This is not the best solution, but I design on the fly, and I feel a pool of objects is needed so I can just reuse the objects and save cpu time creating and destroying them on the fly. This will help when I need rectangles for a particle system (you can't have a zombie game without blood splatter) or with dynamically adding game objects to avoid memory leaks.  

Here is a video of the objects being removed and rember this is pre- alpha.


Well I need to go to my day job. One day I hope to make a living from game development 

Sunday, May 12, 2013

A thought about movement.

I was thinking about how movement would work in my tile game. As the map is right now it is tile based with a total map size of 100x100 and a visible area, the actual tiles you can see, about 10x13. The game starts with the map entierly black and as you tap the adjacent tiles to the player to reveal the map. Think the gameplay for Dungelot, http://dungelot.com/, on how to reveal the tiles. Revealed tiles have a chance of giving something usefull for gameplay. I am considering two ways to implement the movement/tile reveal mechanic.

First, the payer has 5 reveal points and 5 movements points to use. As you reveal reveal tiles those tiles become available to move to. If the player has no more reveal points they must use their movements up before the reveal points are reset. This design leads to the player turtelling up, revealing all of the map and missing the sense of urgency a survival game should have. The player has the right to do this and it is my job to make if fun for them.

The second way, reveal as many tiles as you want before moving but for every tile removed the chance of an enemy appearing randomly will increase. This way you force the player to keep moving and they can still loot tiles with out moving if they choose. This brings up a point of what besides surviving will push a player to give up their comfortable kill zone on the map. If the walking dead has tought us anything about zombie survival --then the answer to this question is FOOD.

The next post will talk about how Food is being inplmented in the game

Saturday, May 11, 2013

Project Z update

I know there are hundred of zombie games out there. Why would I make another one. Well, because I want to. Every article I read about indie game development states I should make a game I want to play. I want to play a rouge like zombie survival base building game with some secret sauce to make it unique. On to the game update.

The timer is in but needs some work with looping.
Selection of game objects is working and I need to process the begin touch and end touch on the map
I had multiple objects working with the astar pathfinding but the second object had it's start position get mixed up with the the last object that called the pathfinding routine. I need to implement a queue so I dont have 2 pathfinding routines running at the same time.

Things related to movement:
     the position of the objects need to be checked before a player or enemy is moved.
     If the player has a ranged weapon and taps on a enemy calculate the line of site.
     If the player is adjacent to a corner wall the damage of a ranged attack will be halved if the wall is
     infront of the player.
General things to think about:
     the interface
     the player inventory
     exploration of the map
     implement the button class
     the role of NPC's
     fire and how it can spread and damage tiles
     same screen multiplayer

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Monday, May 6, 2013

Still no fun yet but...Progress

Thing on the next up list:

The timer is being re-examined to see the proper way of implementing it with the game objects. The game objects have an animation class attached to them and I will also attach the timer class.  After I figure out the callback routines used in the class I am  using.

A gameState for holding various game controlling variables.
    currTile to tell what tile to animate/show selection
    prevTiles to tell the last selected tile to stop from playing the list of UV cordinates and go to the
    gameState playing, menu, paused, map, gameOver, splashScreen.
The game timer will fire every 1 second but it is a variable and can be changed
     the enemy timer will fire every 5 seconds to start
     this will decrease with the noise level
     the enemy can move or attack but not both
     the hero's energy variable will add to the enemy timer
     the hero's will move every second as a baseline

Need to implement the "Secret Game Play" map and inventoty stuff.

The a-star and los fire needs to be reimplemented

First I need to get the checkNeighborTile working when it finds something in the grid[][] map

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Thursday, May 2, 2013

Bug fixing and cleanup

I took a week off from programming, it is a part time hobby of mine, and now I am ready to attack the next set of issues. One bug that killed 5 hours of productivity is finally dead. I use counters to add rectangles to my map mesh. So, 1-100 are the tiles of the map and counter 1000 on up was for the items and player and enemies. I found out the hard way there can be no gaps in the numbering of rectangles being added to the mesh. If you have a break in the numbering then the rectangle shows up and is textures with the whole image map. As soon as the numbering was sequential without gaps...poof texturing worked.

The next issue is the tileType id from Tiled map editor needs to be hard coded so the map draws the correct objects.

Thing I finished:
Game Timer is in with start and stop events on and individual
animate objects with their own framerate
map scrolling in the x direction now works correctly tile updates