Bad Demo, Good Demo

So, here's the final update about Space Combat Sim as a school project. I'll follow up with a postmortem and a bit about what I'm doing in the future.

Bad Demo
The first presentation was to faculty and some industry representatives (fortunately their thing seemed to be anything but games.) It was originally going to be in a classroom setting but moved to the lounge in the student life center due to the number of people attending. The lounge, which happened to have one, maybe two, network ports. Both which were in use by other equipment... sigh. Without being able to play with someone all I could do was crash into scenery. Not much of a demo.

I was able to re-show the project in a lab, with a proper network, but the damage was done. My kingdom for Fraps... and the time (and people) to use it effectively. The fact I didn't have a fallback in case of network failure was a pretty major oversight on my part. Still that last minute venue change was really frustrating.

The most frustrating issue though was the fact the most vocal representative was most interested in how a project was supposed to make money. The fact he seemed more impressed about a group wearing suits than their actual project (which was quite slick) was particularly rankling. Why in the fuck are superficial details such as what the presenter is wearing even considered relevant? Caring more about clothing than the product demonstrated is not something to be proud of!

The impression he left me is that I could have run a pre-rendered video (not a recording of the game) and made up some bullshit about online gaming being worth billions and not been called on the fact I didn't even present a product. That would have saved a couple months of effort... At least the other members of the panel were willing to ask some technical questions during all the presentations.

Good Demo
The second demonstration was at the technology program showcase for the college. This was a 3 hour affair where a large number of people in the various technology programs at the school got to show off their projects. This time a lot more time was given to setup, last time there was a token effort in setting up a router which didn't work at all when used for wired networking. The project was set up on two PCs and running with proper Live accounts. There was some pain as some old bugs managed to magically un-fix themselves, and I didn't actually have the passwords for the Live accounts that were set up for the demo, but that got worked out early on.

The big lifesaver was having Heather (from Slime Cat Blog) and her sister to demo playing the game while I could talk about what it was and how it worked. They would fly around, shoot at each other, be silly, laugh and generally have fun. This attracted a lot of attention from the various people attending the showcase. It also nicely showed what the project was without me having to go into crazy amounts of detail describing how it worked. I'm glad they were there because a lot of the people coming to see the project weren't gamers.

By the way, if you're wondering how those photo****d textures turned out; here's a rendering of the three fighter types.


Not great but still decent for about 2-3 hours per ship I think.

Particles - Part Deux - The Sequel

The Movie - The Game - The... I'll stop now.

It's been another long hiatus since my last entry where I discussed a bunch of semi-boring crap about how stuff gets loaded in Space Combat Sim. Last week (that is the week ending on the 13th) I worked out the protocol for sending the initial game state from one player to another. That part is running somewhat nicely though I've got a bunch of other broken crap to fix before I can really give the details of what I'm doing.

This week, as you may guess, I'm going to talk about particle effects! Yay! Celebration!!! Peanut butter!

Ahem. Last part I discussed some basic theory on particle effects and had a pretty screenshot from an old project. Now I was hoping to talk about a clever method I had devised for making really versatile effects with relatively little shader code and some HLSL snippets. The idea was to store positional, colour and scaling data in the form of textures. Unfortunately this method turned out to be less than workable.

The idea originated when I was mulling over using cubics, or higher order functions to define the movement and other functions for particles. I figured this would result in a great deal of operations since the function would have to be completely integrated every time a particle gets rendered. At some point I began thinking about such functions in relation to producing complex colour gradients that the particles would run through as they did their thing. I got the idea that if I used a texture I could get a great deal of versatility. By using one texture co-ordinate to represent time and using a random value for the second I could have a particle effect with tens or hundreds of subtly different colour gradients with the hardware doing all of the hard interpolation work practically for free.

After a little more thought I figured this could be applied to particle positioning. Much in the way a normal map texture's colours represent vectors instead of actual colours I could have a texture whose colours represent a position in space. Depending on implementation this might add expense in the form of providing a normal, tangent and binormal to individual points sprites. Lots of floats but makes for very simple math in aiming a particle effect in a particular direction.

So, where did this go wrong? A few places. The first, and biggest, was that doing texture lookups in the vertex shader (which is where effects are applied to points sent to the graphics hardware) is apparently unsupported. If anyone knows a way of doing texture lookups in the vertex shader PLEASE TELL ME. This wasn't enough to prevent me from using the texture to provide fancy colour gradients however. Instead of looking up the colour in the vertex shader I'd simply pass the co-ordinates (time, and a random value) on to the pixel shader. So, it's not a complete loss.

I have yet to implement the gradient texture due to some stupidity on my part (I used a texture co-ordinate at first which the hardware happily interpolated for me utterly destroying my lookup values.) I can probably salvage it by passing the lookup in a colour semantic since those aren't interpolated. For now I am lerping between a randomly selected starting and ending colour.

What I have now is basically a stripped down version of Microsoft's Particle3D sample which I'm mutating into a setup that meets my needs. I'll leave you with a screenshot of my particle effect editor tool to finish.

Another Nasty Bites the Dust

As I mentioned in previous blog entries. This development cycle has been far more involved than the first. Mostly due to the fact that it involves a great deal of interdependent parts which all have to be developed at roughtly the same time. In this case I'm getting controls shared across multiple objects, object relationships and physics all working at once to support movement by simulating thrust.

I've figured out most of the math for the physics but it took several hours of effort to learn the basic math enough to even start. It was a few hours ago that I realized I'm starting to seriously diverge from what I want to be working on. What I'm trying to do is make the game look believable. I didn't originally intend to make the game accurate. *forehead slap* Out goes the physics, back to the drawing board.

My new method of simulating thrust is essentially a cheat. I'll just have thrusters appear to turn on and off in relation to the controls. Instead of simulating the behavior I'm simulating the appearance of the thrusters. This is far easier to build saving probably a day or more of work implementing it plus who know how long in getting it to be fun.

First Nastyish Problem Part 2

A nice bit of bone-headedness on my part. I spent around 40 minutes scratching my head trying to find how to get the VertexBuffer from ModelMeshPart so I could render it... only to find that it's in the ModelMesh that owns it. D'oh.

It really helps to look in the right place.