Prophetic Sky

8/27/2009 – Update Pack 1 Released for Townrs Defender, download it if you already own the game, or buy it here!

Highlights:

- Sound and Music added!  Now you can listen to an epic score whilst surrounded by thunderous battle.
- Save and Resume! No longer will you lose your game if you want to take a break, or are interrupted.  Simply choose resume, and pick up automatically from where you left off!
- Interface updates! Now you can tap and hold to run in a direction, rather than tapping continuously.
- Gameplay balance, and many bug fixes.  The game is now even more fun!

Settings Panel:

Added a panel in the settings app to control preferences.  You may toggle on and off the music and sound effects individually.  In addition, you can elect to have errors and gameplay statistics uploaded to our servers, so that we can better improve our game!

Gameplay:

Easy is now easier.  Medium and Hard have been rebalanced to distribute the difficulty better.

User Interface:

Tap and hold to run in a given direction.  Releasing over an enemy will still attack that enemy.
Heroes should run around less when casing the second (cone) skill.
Added additional messages to remind a player to level up, and why a spell doesn’t cast when it is still recharging.

Artificial Intelligence:

Fixed several bugs where enemies would stand around after the player died in certain situations.

Crashes:

Fixed a bug in the map code that would cause a crash.
Fixed a bug in the position code that would cause a crash.

Save and Resume:

Automatic saving is now implement at the beginning of a wave, and whenever the game is terminated.  Choosing resume on the main page will restore a previous game.

Sound:

Sounds added for all combat and game effects.  Title music will play in the menu screen, and several combat music pieces will play as long as there is sufficient memory available.  In the event the iPhone is low on memory, you will be alerted, and the music will discontinue.

August 20th, 2009

Townrs Defender, typically $4.99, is now only $2.99 (US) until our Update Pack goes live!

Our Update Pack will add sounds to combat, epic music, save and resume and many many bugfixes and improvements.  Buy early and save some money! Pick it up on the iTunes store at http://bit.ly/PurchaseOnline

Townrs Defender is the iPhone’s first real Hero Defense game, with tactile combat and role-playing elements.

Hero Character in Blender

Once we’d figured out our implementation details, we needed to pick the tools to get us there. We quickly determined that Blender was well suited to our needs.  Blender is an open source modeling program, whose abilities span modeling to video editing to being an entire game engine.  It has most of the features of 3dsmax or Maya, all of the useful ones, and many more to boot.  Of course, the fact that it’s free helps a great deal.  But honestly, out of all of the open source alternatives I’ve tried over the years (Gimp, Open-office, Thunderbird) Blender is the model of “getting it right” (Alongside, perhaps, Firefox).

Particle Effect in Blender

Our modeling and rigging is done in Blender, and textures are created in Photoshop.  From there, we render out a series of individual frames in the standard 8 directions to a PNG format.  We then use ImageMagick, a command-line tool that comprises a lot of the functionality of Gimp or Photoshop.  ImageMagick gives us the ability to run batch manipulations on the images, and compose them together in interesting ways.

From the resulting PNG format, we compress to PVR, using apple’s texturetool program.  PVR is an interesting format; in a nutshell, it’s a highly regular compressed image format that can use either 4 bits or 2 bits to represent pixels.  The huge advantage to this format is that the iPhone supports it natively, and can render directly from the compressed format.  We found that PNGs didn’t work because a) decompressing the PNG format takes up a ton of CPU time and b) when uncompressed, a 1024×1024 image will be stored at its native size of 4MB.  When you only have 20MB or so to work with, that’s pretty limiting.  For comparison, a 4bpp PVR of the same image is only 512kb – yes, that’s 1/8^th the size.  However, for small images the compression artifacts become very noticeable, so for those we actually double the resolution of the initial images.  For those keeping track, the compressed double-resolution image is still only ½ the size of the original resolution uncompressed image.

BlenderNation also has a quick writeup on us.

We’ve had a lot of requests for insight into our toolset and development process here at Prophetic Sky, so I thought I’d write a few entries to summarize some of what we do here. We’re typically a Windows/Linux workshop, and so we had to make a few adjustments to work on an OSX platform for iPhone development. Fortunately, OSX overlaps a great deal with Linux, and we tend to use a lot of great open source tools.

There aren’t a lot of real statistics for the performance of the iPhone out there, but you can get a rough feel for it by just looking at the existing games out there. Our tests let us to conclude that 3000 triangles/second was a good maximum (we’ve read 6000, but couldn’t reproduce that to be comfortable with it). Even assuming our physics, game logic, AI and special effects didn’t eat into that time at all, if we wanted to fit 20 characters on the screen at once, each character had to be 150 triangles or less. That’s not terrible; many games run with those limitations. But once you realize you still have to fit terrain, trees, towers, walls and spell effects in there, it starts to become very cramped.

Better detail, but less flexibility

So we turned to sprite assets. There are many advantages to sprites – namely that 3000 triangles equates to 1500 sprites on the screen at a time. Also, we can render the characters in much higher detail initially, from source models in the thousands of triangles. The feedback that we’ve gotten on the game leads us to believe that this was the right choice; universally we hear that the game looks beautiful.

There were drawbacks, as well. While we aren’t limited by the rendering power of the iPhone, we are limited by the available memory, and sprites take up a lot of space. In addition, it means our art is limited to running at a fixed frame rate, and in fixed directions – the characters can only run in one of the 8 standard directions, for example. Also, we cannot change the perspective – moving the camera will just show that the sprites are flat.

We’re twittering – follow us for up-to-the minute news, and some promo code giveaways!

The latest glowing review is out, over on TouchMyApps.com! The verdict… Grab It!

“I find myself coming back to it just to see if I can make it a little further…”

In response to requests and feedback, we’re issuing a roadmap that we’ll update over time, detailing what we’re working on now, and working towards in the future.

Update Pack 1:

• New Content: Sound effects! No longer will you have to play in silence.
• Save and Resume: Resume your game after an interruption, or recover from your device running out of battery power.
• Bugfixes: Improved gesture response, reduced crashing, gameplay balance.

Long term:

• Additional Content: Maps, maps, many more maps!
• Additional Content: New elemental weapons to wield, each with a unique playstyle and powerful spells.
• More to come…