That was the XNA 3.1. However, which XNA 4.0, Point Sprites have been removed. The reasoning behind this and some ways to get around this problem can be found here.

The new system has been rewritten to use triangles and triangle lists (as opposed to point lists). During initialization, the index and vertex buffers are created based on the Max particles value (Vertex Buffer = max particles * 4 and the Index Buffer = max particles * 6).

The particle array is a fixed sized array that uses a pair of pointers for rendering and creating particles. The first pointer, first active particle, denotes the first particle in the array that needs to be rendered. The second pointer, first free particle, denotes the first unused particle in the array so new particles can be added in the correct place. The array uses modulo arithmetic to handle these cases. First of all we can have the following:

0
1 - First Active Particle
2
3 - First Free Particle

In this first case, particles 1 and 2 are active while particles 3 and 0 are free. Using modulo arithmetic we can also have the following:

0
1 - First Free Particle
2
3 - First Active Particle

In this case, particles 3 and 0 are active while 1 and 2 are free.

Rendering these two lists has to be handled in different ways to make sure all the active particles are rendered correctly. With the first list (Fig 1) rendering is fairly straight forward, we would render 2 particles (4 primitives) starting from particle 1. With the second list, however, rendering is a little more involved as the particle list will need to be rendered twice. The particles at the end of the list, first active particle (3) to max particles (4), will be rendered first, with the draw call being set up accordingly. Then, with the second pass, the start of the list will be rendered from 0 to the first free particle.

One on the key considerations that were undertaking during the development of the particle system was where to store the emitter settings. Of the two solutions available, the first was to the particle emitter a base class with an Initialize Settings abstract function. The second solution uses a factory function to create the emitter with the desired effects. Whilst the inheritance solution is more flexible (a second function can be overridden for creating the particles) there is a size and speed hit for using virtual functions.

As the particle system is just going into a game, and not into an engine, we don’t require the additional flexibility required from the inheritance solution. This allows us to create the settings object external to the particle emitter and reuse the object to create new emitters.

Hopefully we should have all the tech and play tests redone by the end of the week at which point we will again try to submit the game to Microsoft.

We’ll keep you posted with updates!

- Ben

We tried to send it to Microsoft, only to find that we cannot submit XNA 3.1 stuff anymore. Bum…

So now we are working on the not small task of upgrading our engine to XNA 4.0!

This is a job that may take all weekend but come hell or high water, we will get it done!!!

Watch this space, we can see the light at the end of the tunnel. The game is too close to fail now!!!

- Ben

This is a play through of the first stable version of the game.

It has been a long bumpy road but we are finally nearly there!

You play as a new recruit to the Light Watchman Service. You are give control over several areas whose unlucky inhabitants need to be saved.

You have control of the lights in the area and must use them to save the people stuck there. The people will follow the path that you lay out for them, but they are scared and can get confused if you turn too many lights on.

+ + + + + +

The game is a thinking game. We wanted to present a challenge that is not usually seen in similar games. Each level is designed to be hard.

Are you up to the challenge?

Humankind still owns the day, and has even got used to the ever present danger. Everybody goes about there business, but they make sure that they are home and safe before the kerfew, when darkness falls.

However, every night there is always a few people who don’t make it home. They all know that the only thing they can do is find the nearest light and stay there. As long as they remain out of the darkness, the monsters can’t or won’t get them.

As the light of the sun fades, all unoccupied lights are switched off because power is in short supply. The people caught outside have no choice but to wait for The Light Watchmen to save them.

+ + + + + + +

The Light Watchman service, is an emergency service, much like the ambulance, fire or police services.

For those unluky enough to be stuck out at night the Light Watchmen are the only hope of safety. They take control of an areas lights and provide stepping stones of light towards the nearest shelter.

Some of them are good at this… and some are not so good.

The team met today to look over the game for any problems. It was the first time that we loaded every level in the build. We only found a few small problems, that we are aiming to fix over the coming week.

The most serious issue was lag in three of the levels. We think it is because we had quite a lot of people in the scene and the xbox was struggling to handle all of the update code. Other problems include audio trigger issues and fine resolution issues for those of us who dont have HDTV.

Either way, it all sums up to no majoy game killers! At least it now looks like it was worth Alex and I putting in the extra hours while we were finishing up our degrees!

More wioll follow as I know it

Ben

The time when the darkness descends!

The game is nearly ready to be sumbitted for peer review, and we have a treat for you, some screeshots of the game.

This is a video capture demonstrating our grouping and collisions systems. It was made some time ago and as we have a webspace now I thought it would be cool to share it with you all!

The red dots are those that are in collision with the shadow volume. Those that are white are not!

We were really excited once we got both of these systems working as they are the core systems required to start making our game.

We are making a game for the xbox indie marketplace! It’s called “The Light Watchman” and it’s going to be out soon.

Check back for updates soon!