Javascript motion picture experiment, part 2

I wasn’t very happy with the result for my first take on the motion picture so I decided to revisit them. I did the following:

  • Remove the precision timing requirements by just calculating the film speed, position it correctly and have the shutter be triggered when the frame is passing through it.
  • Fix the shutter so that it’s not open/closed 50% of the time, instead it opens for 10 milliseconds and closes back, regardless of the desired frame rate.


Much better! if frame rate is high enough this looks pretty fluid, but may be too dark! (Note that the 1FPS example is skipping some frames, that’s an artifact of the animated GIF)

To compensate for the short shutter speed I added a white mask to simulate stronger lighting, then I increase the contrast of the film to make it look sharper under the increased lighting.

This also added a natural vignette effect to the movie. The final change I did was simulating a bit of imprecision on the shutter, making it randomly open a bit too late for some frames.

It actually looks much better when running directly (and at higher frame rates), things are happening just too quickly for the GIFs to get all important frames. I’ll clean up and push it to github soon for the curious, for the moment you can check it out online HERE.

I think I achieved what I was aiming for first, however for a real application it may be too tiring for the eyes… may be a hybrid approach (faking part of the visual effects) would be more appealing.

JavaScript motion picture experiment

While developing Curse of Wallachia, I was assaulted with a great curiosity: Would it be possible to emulate the way traditional film movies work using javascript?

The idea was pretty simple: Emulating the “film strip” as individual frames moving quickly (very quickly) on the screen, and then having an overlay area act as a shutter, synchronized with the film strip so that it showed a single frame at a time.

I decided to stream my adventure, which involved a lot of exploring the different options. You can check it out here and here

The goal was to make it so that the movie played at lower FPS than the actual game was running. I ended up doing the following calculations:


  • SHUTTER_HEIGHT in Pixels.
  • TARGET_FRAME_RATE in Frames per second


    • in Milliseconds per shutter cycle
    • Each shutter cycle consists on it being opaque and then transparent for the same amount of time.
    • in Pixels per millis
    • How quick should the film move so that a single frame is shown for each shutter cycle.
    • Converted to pixels per frame.
    • All sprites in the film strip move this distance on every frame.

Here are my observation after the first try:

  • It’s very hard to time the sprites correctly to move at this high speed and sync their position with the shutter. This is caused in part by the varying real frame rate and the high precision required for the timing.
  • Even if this was possible, having the shutter block the image 50% of the time reduces its brightness a lot (if I’m correct, they fixed this using stronger reflectors historically).
  • Ultimately, I missed the fact that the persistence of vision effect wouldn’t be achievable at low frame rate speeds so in order for this to work I’d have to work with higher frame rates, complicating the emulation even more.

I decided to give up this idea. I realize I may be doing something wrong so if someone wants to take on the challenge (or elaborate on why it’s not feasible) please post in the comments!

Later on I thought on alternatives to achieve my goal, I figured the only way to go was is faking both the Phi phenomenon and the Persistence of Vision effect as follows:

  • Keep the motion of the “film strip” using the same previous calculations.
  • Remove the shutter altogether, instead put a “still frame” sprite on top of the film strip. (This simulates the persistence of vision effect)
  • As the sprites from the film strip come close to a the “still frame” sprite, “burn” the sprite image into it. Since the film strip is moving quickly, this will simulate the phi phenomenon at lower speed (giving it the desired “retro” feel).

Here are the results:


I’m pretty happy with these results, admittedly I could have cheated and just put a blurb of pics as the film strip, since they are barely noticeable when over 8FPS… but this was fun and I think it feels more authentic 🙂

Finally, I made the still frame move around a bit when captured to simulate a bit of “jankiness” and imprecision.


If you have followed the development of Curse of Wallachia, you may have an idea what I’m going to use this for.

“Voyage” is born, and how it handles land border tiles

Thank you all for your feedback regarding my last post, after much debating here’s my current mindset:

  • Current version of Expedition, while not covering the whole planned scope, is already a playable and potentially enjoyable game which requires some UX fixes to be shipped.
  • The gameplay ideas which composed the original scope for Expedition are worth implementing in a different format which can be appreciated by a broader audience.
  • I won’t be able to work extensively in the full version of expedition in the following months, thus it will likely be released in 2018.
  • The current version of Expedition can be released soon, freeing myself of the burden of having wasted trillions of dev time milliseconds.

That brings two games I’ll be playing in the following months…

Game 1: Release “Voyage”, the current version of Expedition

First thing I did was rolling back a lot of the changes made in the last months of development on 2012 for both Expedition and SERF when trying to modify the engine to run continuously and show animated sprites, thanks to the power of git (and a well done migration from SVN), I was able to roll back to about the status of the last public version (0.5)

Then after giving the game some playthroughs, I defined 3 macro areas to work in:

  • Minor and effective UX changes: Remove redundant data and interaction steps that were in place to allow future functionalities which will no longer be. Polish appearance without investing a lot of time on it.
  • Polish mini colonization facet: Remove clutter, simplifying the way settlements work while at the same time integrating them with the game winning conditions.
  • Balance game: Experiment with data to ensure the game can be won in around 5 voyages.

Upon examining the Java code I found out it isn’t THAT bad. There’s a nice structure, an engine which was unfortunately not meant to support animation from its onset.


One of the things people suggested and I thought would have a strong impact was adding the “beaches” or land borders to the overworld. I toyed around with many ideas while I familiarized myself again with the code, and in the end decided to include it as part of the “rendering” process instead of it being part of the map model itself. At first I tried to do something similar to what I had done with Ananias walltops: Analyzing different scenarios and deriving rules based on them.


However, I thought that approach may not be needed in this case since this was simpler… doing that “2.5D” appearance for Ananias was sure a lot of work, but here it is an overhead view so I figured there may be a simpler solution. After some googling I found an old article which was pretty useful and in which I based my approach.


What I’m doing is, for every visible water map cell I’m checking the surrounding cells to see if there’s land around. Each one of the 8 directions has a weight assigned as a power of 2 (with some additional tweaks for the ordinal directions), the sum of these weighted values determines what tile to draw over the ocean.

boolean[] mask = new boolean[]{
    upLand || leftLand || upLeftLand,
    upLand || rightLand || upRightLand,
    downLand || leftLand || downLeftLand,
    downLand || rightLand || downRightLand
int sum = 0;
for (int i = 0; i < mask.length; i++){
    if (mask[i])
        sum += POW_2[i];

There’s a map which maps values for this sum with base indexes on the tileset as follows:

POWER_MAP.put(128, 1);
POWER_MAP.put(224, 2);
POWER_MAP.put(32, 3);
POWER_MAP.put(148, 4);
POWER_MAP.put(41, 5);
POWER_MAP.put(4, 6);
POWER_MAP.put(7, 7);
POWER_MAP.put(1, 8);
POWER_MAP.put(47, 9);
POWER_MAP.put(151, 10);
POWER_MAP.put(233, 11);
POWER_MAP.put(244, 12);
POWER_MAP.put(239, 13);
POWER_MAP.put(191, 14);
POWER_MAP.put(247, 15);
POWER_MAP.put(253, 16);
POWER_MAP.put(255, 17);
POWER_MAP.put(5, 18);
POWER_MAP.put(132, 19);
POWER_MAP.put(160, 20);
POWER_MAP.put(33, 21);



Additionally, there are three variations for the beachfronts, what set to use is determined by using a hash function over the location of the cell on the world.

I also cleaned up the UI removing redundant info, changing the font for something more readable and relaying out everything to avoid wasted screen space. In the end I decided to support only the “Denzi” 32×32 tileset, which looked pretty good when I added the “beaches” and resized the viewport to 600×450.

I also worked on trying to add a full screen mode to the game. So far I have had partial success on this, I was able to scale part of the game but the engine works by having two layers: one where graphics are drawn (which I could successfully scale) and another one with UI components based on Swing which I think will be too hard to work with. I also found out the current way of finding the screen dimensions is troublesome on dual screens or scenarios where there are system menus taking part of the screen (although I think this could be fixed by using actual window measures instead of display size)


This is a hard one… I’m thinking on ditching fullscreen and make it work just windowed, although I recall some experiments on CastlevaniaRL back on… 2004-2005? which made full screen work without manually scaling (and which scaled Swing components as well)… I’ll have to dig a bit on it and see how it works in modern machines.

I’m planning for a release of this in around 2 weeks.

Game 2: Restarting work on the full version of Expedition

Expedition will play and look a little bit like a RTS, with miniature AI-controller units (and probably lots of them in some scenarios), following the player around an infinitely large world where Exploration is the main concern. It will NOT be a RTS, you will have direct control only over a single unit, and the game won’t focus on finding and exploiting resources on the world, nor placing building strategically or even tactical battles. In a sense it will be more of a toy, a miniature world you can explore with your miniature explorers.

Some initial ideas for the game, although my current vision would be a bit different with smaller looking units and a different art style.

Player created content will be a huge part of it, it will include an editor where players can build their own scenarios and worlds, themed in their favorite series or historical events.

It will feature seedable procedural world generation and most of the features defined in the current roadmap (which will soon be updated to remove some things that defintively won’t go)

Given these requirements, I am still not sure if Phaser is the way to go… I’m considering using Unity for it, but that’s a choice that may still wait for a bit.

Ananias introspection: Content Creation and Balance

This new series of blog posts will be based on /r/roguelikedev FAQ Fridays, a long standing series of discussions where roguelike developers share their techniques and experiences around a single topic.

FAQ Fridays Revisited # 6 Content Creation and Balance (original)

How do you decide what mobs/items/abilities/terrain/etc to add to your game? In any good roguelike content creation is inseparable from the concept of balance, so your methods of balancing content are certainly within the scope of this discussion.

Ananias has a fairly static collections of monster races. They were first added based on the original rogue monsters and with a single criteria on mind: each race should have an unique feature or ability.

Sometimes implementing an ability is costly and there’s the temptation of parameterizing it so it can be reused with slight variations, but I think it gives more character to the monsters having their distinctive skills. This means Ananias doesn’t have Ice, Fire, Water, Earth and Thunder dragons whose only distinction is the “type” of their attacks, I’d rather have a single Dragon monster distinguished by a strong ranged attack.

The uniqueness of an enemy race is not defined only by their active skills, their stats are also put in consideration. In this case they are assigned relative values first (i.e. orcs have high attack and medium hp, Lizardmen have extreme high attack and low hp). This is balanced so that races without cool active skills get some advantage stats-wise.

The dungeon is then split into 5 areas with increasing difficulty. Mob races are grouped thematically on these areas and then assigned final values for their stats by scaling their relative values to the difficulty level of the group they are in. In order to do this, I do a projection of the average stats for the player on each one of these areas and then I apply some simple general rules (for example, a strong monster may kill the player in 5 hits, a monster with low HP should be killed by the player in a single attack). These define ranges within which the stats of the final monster will be placed.

Items follow a similar model. For weapons and armor I started with a list of preexisting graphics (the artist made them on advance for a different game using his own creative criteria) then based on they appearance I assigned them relative values (high/mid/low) for damage and integrity (how likely they are to break), and then I grouped them on power tiers to define their final stats. They also get assigned a generation weight representing how likely they are to be added to the levels, this value is used in level generation along with the power tier to select the items to be added.

Player abilities are guided by the same principles of uniqueness. Ananias is strongly classed, and each class has unique passive skills that guide players into adapting different playstyles for each one. The process for player classes is similar as with the monster races, they are balanced based on their skills and relative values for their stats. (Except for the shepherd ;)).

On a final note, I’d like to say that while seeking to balance the different stats is worthwhile (to prevent your game from being utterly broken), it’s also to some point a futile exercise, since the variability of the game and the player’s choices create a lot of unpredictability, specially as journeys progress in games which provide long and open experiences. This is not necessarily a bad thing, and a little bit of unbalance is not always harmless since it allows the players to find strategies and challenges within the game.


A better build and deploy process for hybrid apps?

The current build and deploy process for Ananias takes a lot of time and requires lots of focus and bandwidth. Everything is done manually (and is thus prone to errors). Most of times I just can’t afford to release for all platforms, and I forget to announce thru all channels.

The parts are a bit cumbersome since they don’t have a CLI and it requires some back and forth, while also adding a dependency to an online service (for how long is it going to work?) I’m going to experiment with some native crosswalk builds to see if that step can be saved.

But probably what takes more time is the manual process to be done for each different storefront via its own web interface. Each one requires different info, and all uploads have to be started and monitored manually. It’s pretty uncommon for a store to supply a command line tool.

May be I should automatize parts of this? Someday I may do that, in any case it’d simplify packaging but wouldn’t make distribution any easier.

This is the current process executed for each new release of Ananias:

  • Mark the new version in the source code (client and server)
  • Generate a new JS bundle using browserify
  • Upload new build to web ( (About 15MB) (Only Standard edition)
  • Deploy new server version and restart (About 1MB) (including executing migration database scripts)
  • Use nwbuild to generate the executable packages for Windows, Mac and Linux
  • Rename the directories and zip them
  • Upload to via web interface (About 200MB )
  • Zip web directory
  • Update config on for next version
  • Upload web directory to (About 15MB)
  • Hit the build button on, wait for build to finish
  • Download APK packages from (About 150 MB)
  • Unzip package, copy release APKs (one per architecture, x86+arm7) to APK directory
  • Run script to sign and align APKs
  • Sign in to google play developers console
  • Upload both APK (About 100 MB)
  • Build change log from git commit messages
  • Summarize change log for Google Play
  • Upload both APKs to Amazon via web interface (About 100MB)
  • Upload to indiegamestand via web interface (About 200MB)
  • Upload to gamejolt via web interface (About 200MB) (Only Standard Edition)
  • Upload to IndieDB via web interface (About 200MB) (Only Standard Edition)
  • Set for iOS builds
  • Hit the build button, wait for build to finish
  • Download xcarchive (About 50MB)
  • Open xcarchive in xcode organizer
  • Submit to App Store
  • Wait for processing
  • Go to iTunes Connect
  • Go to Testflight / External Testing
  • Select new build to test
  • Wait for beta review
  • Go back to Testflight / External Testing
  • Set the new build as active.

The process should be executed twice, once for the Standard Edition and then again for the Fellowship edition.

THIS IS A LOT OF WORK. WHY CAN’T IT BE SIMPLER? This process takes out HOURS (Not exaggerating) of valuable and scarce development time for an Indie dev.

Why can’t I just simply update a single web endpoint, and have all the clients deal with the updating? they have to deal with it anyways, they just have to do it with their own, different store.

Also, the game is already multiplatform, if your platform has an HTML5 browser, like all modern platforms, you can play the game (Yes, you can even play the game on a PS4), then why go through all this?

I understand the advantages of having a downloaded app… people wants to feel they own the app, and they want to play their games while offline or in poor network conditions.

It would be awesome if the app could automatically check and download the updated scripts and required assets. This is not a new idea… some people has already tried but there are some obstacles:

  • Both Play Store and the AppStore are not very clear about their support of this model. You may be risking your app being taken down for not complying with the terms of service. They are also not MEANT to work like this, so you are always fighting against their nature.
  • For in-dev games, the player wouldn’t be notified a new version exists unless he runs the game or you implement some kind of push notifications.
  • The system has to work perfectly, if it doesn’t then your players will be stuck with an old version, or will be unable to play offline, or will end up with a malfunctioning app.
  • Another thing to consider is that this would prevent players from updating the web runtime in which the game runs, although I guess that may be fixed via a normal update.
  • If the player uninstalls the app or erases its data cache, they will have to redownload all assets.

There is a cordova plugin (cordova-app-loader) which adds support for “hot updates”. It seems to work but has some issues (based on what people reports). I don’t know of any similar tool for node-webkit / NW.js, I guess it’d have to be done manually.

Any thoughts?