Auto Assault

At the time, the intent was to change the sky color a bit and perhaps add some fog or dust in the distance, but as the potential for variety became clear, the idea went a lot further – we found that more extreme weather effects were possible and could lend a great sense of presence to each area.  Modifications were made to the particle system to enable emission using the camera as a base location – these particles can travel along with the camera at all times, or they can be spawned into worldspace based on the camera's position and stay where they're put.  These two approaches can be mixed and matched even within individual weather systems.  For example, a rainstorm might be made up of a tall cylinder of quickly falling rain that travels with the camera, as well as a wide disc of constantly-generating fog that always spawns based around the viewpoint but remains stationary so that it can be driven through.  In addition, tags were added to the particle system that allowed any particle that strayed too far from the camera viewpoint to teleport directly to the other side of its emitter zone, meaning that we can now use far less particles in an effect than would normally be possible – in fact, as dense as the weather systems appear to be, almost all of them top out at 300 particles total. 

As we began to implement the new code and play with the possibilities it afforded, each zone became its own little world with a lot of unique character; an overall map could hold to a general environmental theme while its sections could vary widely.  Instead of subtly-changing sky color and a choice of light, heavy, or no haze, our horizons were expanded, and the game came alive with all kinds of weather and environmental effects – there could now be low-hanging smog in cities, shimmering heat waves in painted deserts, and curtains of freezing drizzle slowly falling in sheets from the sky.  In one zone, a huge pile of burning garbage smolders away, and high winds whip black smoke, hot streaking embers, and blowing trash across the land in a torrent of soot and filth.  In another, yellow radioactive haze from heavy nuclear fallout is alive with the subtle crackle of electrical discharges.  Areas steeped in alien contamination are awash in floating green spores that seemingly defy both gravity and wind, spreading to cover the Earth, and blinding sandstorms sweep across barren wastelands dotted with slowly moving dust devils.  Especially fun are the areas controlled by the TemperNet, whose ubiquitous red glows now underlight the clouds above and cast an eerie, sullen red over all the land.

To give a specific example of how much better one area has become, let's focus on a Biomek zone called Flash Freeze for which I created an entirely new weather system.  As the name implies, it was meant to be a very cold and inhospitable place, but the lack of moody lighting and precipitation kept it from evoking a strong response.  Before the change, the only thing that conveyed the chill was the presence of snowy ground textures.  Now, though, the area truly reflects its name.  I began by making a special particle texture that allowed many hundreds of snowflakes to be believably placed on one card.  To make the snowfall read as more complex than it is, I used a simple trick – I mixed some high-resolution single snowflake particles into the overall tempest.  It's effective – the viewer's brain picks out the high-res images and interprets them as being closer to the camera, while accepting the lower-res particles as more distant.  I generated the snowfall high up and to the west of the camera, then set up a fierce wind with a lot of swirling randomization, blowing the snow right into the area of the player's car.  I also added some snowy powder blowing up from the ground in the direction of the wind. 

One other trick was utilized as well – I brought the snow's render order up in the chain, which means that large snow blowing past in the background also appears to be small snow moving in front of nearby objects.  Four different lighting and fogging schemes were created for our four times of day (dawn, daytime, dusk, and night), and when all lighting and particle effects were combined together, the zone became something far different from what it had been before.  Snowy textures still blanket the ground, but in addition, all the missing pieces of the puzzle are now present.  The sky is an impenetrable mass of featureless cloud.  By day, what little light there is appears pale and gray, and at night, muted and washed-out blues blanket the ground.  Visibility is poor at all times – a thick white fog envelops everything in sight – and a massive blizzard is in full swing, the wind swirling in violent gusts as a nearly solid wall of falling snow blasts out of the west.  The area's chill mood and windblown storminess almost make you think you can feel your car's heater blowing on your feet as your tires fight for traction on the ice.

Creating the new look and feel for the game's maps has been very satisfying, and the new look and feel of the zones has been more effective than any of us would have guessed.  The sheer number of weather systems, environmental effects, and world lighting variations that we've had to create has been daunting at times, but there is no question that it has made Auto Assault into a much better game.  We can't wait to see how players react to all the surprises they have in store for them as they hit the road and explore our world.  Happy driving, and try not to get hit by lightning!