Technical Talk

During the development of Army of the Damned we also started another first person shooter project. The plan is to create a similar game like the zombie game, but with a more arcade type of gameplay and graphics. Today I want to talk about how we are going to do the 'Shooting' in this game. You might think, 'Well it is a first person shooter just like all the others, so what is the point of discussing this?', which in fact is pretty much true. But what we want to do is make all of the bullets visible. Not just instant hits, as we did in the zombie game. The main reason for this is to amplify the arcade feel of the game. It also changes the experience slightly, because it takes a slight amount of time for the bullet to hit it's target.

The technical difficulty of these visual bullets doesn't come with the bullets themselves. They just function on their own. When spawned they move forwards, if they hit something they die. And while a bullet is 'a life', it is visible to the player.
The problem comes when shooting the bullets, or better said, spawning the bullets, from the first person perspective. Normally what you can do to 'shoot' from a first person camera, is just to shoot a ray down the center of the camera's transform into the 3D world. If it hits anything create a bullet hole, hit an enemy or something else depending on what the ray hits. But when having visual bullets, and a visual weapon in view where the bullet appears to be coming from it isn't that simple.


This figure shows our problem:

If we just spawn a bullet at the end of the weapon's barrel, and shoot it in the direction the barrel is facing it will never get to the target the player's aiming for. It does go in the correct direction in general, but this will be unusable when having targets on a decent distance. It will also look very strange because the fired bullets won't move towards the displayed crosshair in the interface, which makes the crosshair in fact pretty useless.

The solution is to shoot a ray first from the camera, the same way you would do when shooting 'directly'. This should give you some sort of intersection point in 3d space. Then it is time to cheat a little. The bullet we are about to create should spawn at the end of the barrel, but not be pointed in the same direction as the barrel. Instead it should be pointed at the intersection point we got from the ray. This will make sure that bullets always travel towards the target or object the player is aiming at. It will look correct because the bullets will always move towards the crosshair in 3D space.

The only problem occours when the first ray fails. We don't have a reference point. A simple but yet effective solution to this problem is to calculate a intersection point far a way from the camera. And then point the bullet to that new location.

Until next time,

-Joep

Pimping art for stills and print

The past week we've been finalizing our zombie shooter "Army of the Damned". At this stage we need to prepare the artwork for marketing and print purposes, which of course has to look much better then in-game screenshots or standard renders and also must have a much higher resolution. Luckily I took this into account when creating the game's main menu which in-game is displayed at a resolution of 800x450. For this image I tripled the size to 2400x1350 pixels, which is more then enough for what we want to do with it.  

It's always good to figure out what you want to achieve with the image before starting on the artwork, this will keep you from creating art which in the end you don't need.

For this image I wanted to show a detailed player character, some zombies closing in on him and a plane dropping a bomb in the background while keeping in mind the title and menu would be displayed on top. I also wanted the image to have a grindhouse look. After some quick layout sketches I posed the 3D characters and rendered an image which can be seen below.

As you might have noticed the rendered image looks a bit bland, the big zombie on the left has too little contrast and there is no clear light-source, no problem we're going to fix all this in Photoshop!

First we need to determine where the light comes from, in this case most of it will come from the explosion in the background. In Photoshop I placed a layer on top of the character where I painted the lit areas with an orange color and set the layer to color dodge. 

On another layer I painted the shadow area's with a dark color and set the layer to multiply.

Next I added the background which is composed out of a sky, mountain, plane and explosion image. I also added some smoke coming form the gun muzzle. 

The image is getting there but it still looks too clean and the background looks too detached from the foreground. First I added some noise on top of the image and a "scratched film" layer to make the whole thing look old.

When you look closely you might notice the left side of the image has a red hue and the right side a green hue (red=bad guys, green=good guy). This is achieved by adding layer on top set to color dodge (of soft light) and lightly using a red and green brush. 

Finally I placed another layer on top which is set to overlay, with a white brush I painted over the area's which needed to be more brightly lit. These where mainly the explosion area and the players chest.

So that's how you pimp an image!

Cheers, Matt

The zombies are coming..

Hello!

Time for another blogpost today. First of all I want to bring some good news.. Our zombie shooter is nearing completion, it is almost done! Last week we did some playtesting to find and fix bugs and glitches. But we actually couldn't stop playing the game itself! Stay tuned, the trailer is coming soon ;)

  

Screenshot Zombie Shooter

The playtesting, or QA (Quality Assurance), is very important. A game, when released, should work. And not just be filled with bugs. During this process bugs are found and listed to be fixed after the QA session. If someone encounters a bug while testing. He or she creates a so called 'QA Ticket'. The bug or glitch is explained in the description of the ticket and also the steps to reproduce the bug are written down. This in particulary is important, because the programmer who's going to fix the bug can reproduce it for debugging. Imagine something very simple like this:

Problem: The sound isn't muted when pressing 'Mute Sound' in the options menu.
Procedure: 1. Start the game 2. Go to the 'Options' screen 3. Clik the 'Mute Sound' button.

This is a straight forward bug, and probably not so hard to find and fix. Bugs that occour during gameplay are much thougher to reproduce. Sometimes the player needs to be at a specific location within the game world. If so, we add a screenshot to the 'QA Ticket'. So the programmer can go to that location in-game, and follow the steps to reproduce the bug. Instead of starting a process of 'Trial and error' just to reproduce the bug in the first place.

The next step is to fix the bugs ofcourse. First the blocker ones, the bugs that cause game freeze's or prevent the player from making progress. What I mean by 'Making process'; A gate for example that should open after some actions, and it doesn't. The player is then not able to walk through it towards the end of the level, and thus not able to finish the level. Then the other critical bugs are fixed. Such as sound/music bugs, graphic issues, getting behind the boundaries of a game level where the player shouldn't be etc.

If the blocker and critical bugs are fixed, a new QA session is behing held. The QA process starts again until the game is ready for release.

Happy QA'ing ;)!
-Joep

Tell me who you are

Hello developers/fans/people who accidentally landed on this site,

Today we have tested one of our new games, which is (surprisingly) a super secret game.
Of course this is a very interesting process. If you like to read more about test days, you can read about it in an earlier post of Stijn.
But unfortunately for this project there's not much to tell, because the game is such a big secret. Instead of boring you by telling how great this game is going to be and that you can play it really soon, I like to tell you about something else: target audiences.

Target audiences? Why?
As you may already know, at Xform we like to make games that we ourselves love to play. But that doesn’t mean we don’t listen to our player base. We just want to know who they are, where they are from and why they especially like to play our games.

Target audiences are very important. For every product. For every game. Whether you are creating console games, mobile games or browser based games, you need to know what kind of people (are going to) play your games.
Are they kids or adults? Male or female? At what age? When do they play games and how much time do they spend on it? Do they play alone or with friends?

Knowing who they are and what they like is very valuable information when making a game. It’s most common to use this information for marketing and promotional activities, but you can also use it for game design.
This doesn’t mean you should base the entire game production on target audience facts. After all game development is a creative process and it is fun to surprise your audience with things they don’t expect. But, for example, if you know that your type of game is mostly being played by people that do not spend more than half an hour per day on gaming, then it doesn’t make sense to create levels with loads of side quests and fights that will take at least two hours to finish. Although this may seem quite obvious, there are just too many games that don’t match with their target audience.
You can also use your target audience analyses to treat your audience on extras like special enemies or funny easter eggs. They will appreciate it!

How to define my target audience?
To define your target audience you have to do research. And of course there are millions of options to start with this.
If you have a lot of money you can spend it on an exclusive research institute that will do all the work for you. Or you can hire some specialists and start a research department at your own office. Unfortunately, at Xform we don’t have this opportunity yet. We have to do the research by ourselves, which is actually very interesting.

My advice for starting with your research is to keep it small and simple. Stay close to your company and take advantage of all the information about game target audiences that already exists. Believe me, you can spend hours on reading books and web articles about this. Now it’s your task to find out which information is valuable for your game.

If this is the first game you’re working on you might start to take a closer look at similar games from the same type of platform. What kind of people play this games? They might want to play your game too.
When you already developed some games you can also do research on these games. Find out what’s the target audience from your previous games. Internet offers you some interesting tools that might be useful for this. Every social media site has an option to track down user data and information from your fans.

We also started to use Google Analytics for our Xform website to see who are interested in our company and games. So now we can see how many and for how long people visit our site, if they were looking for something in particular or that they just accidentally stumbled upon it.
A lot of information might surprise you. I didn’t know most of the visitors on our homepage are from Brazil:

visits on the Xform website (last two weeks)

Have a nice weekend!

- Shirley

Replay fun

Dear readers,

I've been working on another car game and last friday afternoon after doing some boring stuff I felt like doing something fun and that could be done quickly: a replay function. None of our games currently have this, but for the game I'm doing now I think it would really add something.

Before we can replay anything of course we need to record. The first thing that comes to mind is to simply store our key input and on replay the stored key input is used as input for the car. But as we're using a physics engine which I don't trust to be deterministic (the same input results in the same output) it would lead to a different replay which of course is not what we want.

Another approach which is easy and sure to work is to store the transforms of the car each frame in a list and when on replay simply go through the list and setting the car model to the stored transform. This is what I currently do and it works well. But let's analyze it. We're running at 30 frames per second and thus storing 30 transforms per second. For each minute of replay we store 30 * 60 = 1800 transforms. Assuming each transform is stored as a 4x4 matrix of floats, so 16 floats at 4 bytes per float: 64 bytes per matrix. And so for each minute of replay 1800 * 64 = 115200 bytes. Considering today's RAM capacity in computers this is peanuts. But this of course is only for a single car and additional actions have not been recorded (for example car damage, firing of weapons, etc). One way to reduce the size of the replay list would be to store the transform every X frames and interpolate between transforms, although you do lose accuracy with this approach. Another way is to only store transforms when they've changed 'enough' with respect to the previously stored transform. In this way a car that does not move would not cause the replay list to increase in size.

With a replay you can think of simply watching what you (or someone else) did. Currently I implemented it as a replay while you're playing: like a ghost rider (See image below). In this way you get the feeling you are competing which in my opinion adds to the fun and I hope the option will be there when we release the game.

Image from 'BMX Ghost'. A ghost rider is shown displaying the best round you previously played.
-- Stijn

New prototype

Hi all,

A few weeks back Stijn started programming a new game prototype which is basically a downhill ski-game with a special Xform twist. Last Monday I was put on the project to create a track and some (temporary) graphics for this prototype. The game just needs to look and play good enough to get a good impression of what the final product could be, therefore I won't put a lot of time in designing and fine-tuning the track. I'll keep you guys updated on this project when (and if) it goes into full-development.

Cheers, Matt

New Game Sneak Preview

When you don't have anything to write about you can always post a super secret screen of an upcoming game!

Greets,

Diederik