Rates Given

101

Quake / Re: Carter glitch on q2dm1?

Frag of the Week

Okay, a couple key concepts for understanding Quake:

• Quake uses a right-hand coordinate system where positive X is "north" positive Y is "west" and positive Z is "up".
• Quake BSP is a partitioning of 3D space by two volumes, recursively, until every volume is convex. The barriers that describe these volumes are planes.
  
• Planes in BSP are described by a normal vector (direction in 3D space) and a distance (offset from origin, or the negated center of the "surface", if it helps to visualize it that way).

So an axially-aligned (read: flat, non-sloped) floor surface that's at -128 units would have a plane definition of (0, 0, 1) @ 128. That's a normal vector of positive Z and a distance of 128 units. Quake planes use inverted distances for some reason.

The dot-product of any two vectors essentially determines if they face each other, and how much. Vectors with a dot-product less than 0.0 face one another (read: collide), while those with dot-products greater than 0.0 would never intersect. But that's assuming the vectors start at the origin (0, 0, 0). So each plane's distance from the origin must be factored into the equation to determine sidedness correctly (consider two surfaces where one faces east and the other west, but they are "behind" each other -- e.g. the outward facing surfaces of your average column or pillar or door).

You can find this "dot-product minus distance" test throughout the Quake code base, in everything from pmove to the BSP compiler to the renderer:
http://jdolan.dyndns.org/trac/browser/quake2world/trunk/src/client/renderer/r_bsp.c#L142

The origin has no "pull" on your player's position in pmove. There is intentional precision loss (conversion of 32 bit floating point to 16 bit integer) to save network bandwidth. And gravity in Quake's pmove is nothing more than a constant acceleration applied in negative Z (which is probably the least crude approximation in all of pmove.c ).

Hope this helps!

Edit: So, after I wrote this, I thought for a moment about the intentional precision loss in pmove (converting to 16 bit ints), and re-checked the code. It does in fact favor rounding your coordinates towards the origin. I don't think this could be considered significant, but there is not a measure in place to counter it:
http://jdolan.dyndns.org/trac/browser/quake2world/trunk/src/pmove.c#L993

102

Quake / Re: Carter glitch on q2dm1?

Demonstrates Exceptional Knowlege of the Game

Bugs like this are all a consequence of floating point math done at 32 bit precision and / or large time intervals. The way that Quake works, basically everything from physics interactions to determining visible surfaces relies on calculating plane-sidedness (dot-product of origin or view vector against plane / surface normal vector, offset by plane distance).

Physics interactions in Quake happen once every client-packet for players (variable, generally 8-30ms) or, for AI and items, once every server-packet (100ms fixed). That's plenty of time for collisions to fall through the cracks, so to speak, particularly for fast-moving objects (ever shoot a rocket through a really thin wall?) On top of that, 32 bit floats provide plenty of precision loss for near-misses to be counted as collisions and vise versa.

Where something should have hit and slid along the wall or maybe exploded, it instead passes [partially] through the wall. For rockets, this is generally harmless unless the wall is very thin. For grenades, they might stick to the floor in unusual ways. In the case of your player model, passing only partially through the wall results in you being stuck inside the wall at the very next frame.

The player movement code doesn't cope with these conditions, and continues to build up bounce-off velocity (which, under normal circumstances is what keeps you running at normal speed when you intentionally run along walls). When that bounce-off velocity finally builds to a high enough value to again trigger a missed collision with the wall you're stuck in, you shoot out of the wall at a ridiculously high velocity and instantly crater

Math is fun.

103

Science / Mr. Fission: Salt reactor runs on nuclear waste

Informative

The Waste Annihilating Molten Salt Reactor (WAMSR) runs on materials the industry currently discards as waste:

http://www.theregister.co.uk/2013/03/14/nuclear_reactor_salt/

Most conventional nuclear reactors – in the US at least – are light-water reactors, but this design has a number of disadvantages. The reactors only use about 3 per cent of the potential energy stored in the uranium pellets that power them, and the resultant waste still contains enough energy to be radioactive for hundreds of thousands of years. The average US plant produces 20 tons of such waste a year.

They also suffer from safety problems, since an external power source is required to cool the reaction chamber and to shut down the plant if necessary. It was the failure of these power systems (owing to the tsunami cutting both power to the plant and swamping the backup generators) that caused Fukushima's reactor problems.

The WAMSR takes "waste" fuel pellets and dissolves them in molten salt. The fluid is then pumped into a graphite core to induce a reaction and generate heat, which is extracted via a heat exchanger and used to drive steam turbines and generate power.

The design is much more fuel-efficient than light-water reactors – using 98 per cent of the potential energy in uranium pellets – and a WAMSR unit would produce just three kilos of waste a year that would be radioactive for only hundreds of years rather than hundreds of thousands.

With around 270,000 tons of nuclear waste available worldwide, the reactors would be enough to supply all the world's projected energy needs for the next 70 years. As a side benefit, this could also reduce nuclear proliferation since countries would no longer have to manufacturer nuclear fuel.

As a safety feature, WAMSR's liquid-fuel pipes are connected to a drain plug of salt that has been frozen solid. If humans aren't around and the power to the plant fails, the plug melts and the nuclear fuel drains into a holding tanks, cools, and solidifies over the space of a few days.

It's also supposed to be less expensive to build than prior reactors.

If this thing really works, what a freakin win-win.

104

tastyspleen.net / Re: Ratings

DO YOU EVEN LIFT?

Um,how do you get rid of the huge grey box that appears in every post?

105

Trouble Shooting / Rofl, wtf a tdm bug?

Racist Ignoramus

Didnt note this when i was playing but look at 8:34 when i am at lift and
chaingun stairs at 8:11.

Havent seen it before so is it
some kind of frame bug?

 

106

Quake / Re: Possible Pak File?

Whoosh! You done missed the joke thar Cletus!

Who elected you to be fried anyway?

Who had a job application for a haunted house?

107

Q2 Training Camp / Re: Mod Explanation - Railwarz CTF

Redundant

well railz is a particular mod. good for practice but not much else. loses it's luster after a while. one weapon 1 strategy. why not just choose Lithium CTF? lithctf.yolasite.com 

108

Q2 Training Camp / Re: Mod Explanation - Railwarz CTF

Whoosh! You done missed the joke thar Cletus!

Hmmn, maybe. Do you know if my dodge bot will work or not in Lithium CTF first? I don't want to install it and find out it doesn't.

Maybe which version do you have installed ? 

Quite a few logical fallacies in these statements.

http://www.don-lindsay-archive.org/skeptic/arguments.html#coincidence

Argument by slogan followed by outdated information,
Ad Hominem: Argument To The Man (Needling)
Reductio Ad Absurdum:
Argument by Rhetorical Question:

just to name a few. 

109

Quake / Re: Sum people on dm

Amazing Conspiracy Theory Bro

On a real note, I heard the 1%ers have gotten a bad rep like the Hell's Angels and several other biker communities.  Like a lot of what people think about them is either straight-up made up, or misconstrued from something that happened ages ago.  Like the whole thing about treating women like property and female slavery, yet when you talk to the women in the 1%ers, a lot of them actually love being in it and the last thing they are is slaves.  I kinda wonder where this shit starts up to begin with.

110

Jump & Trick Demos / Re: for 2dum

Appears Not to Comprehend Game Fundamentals

Hey man, there's no official definition of Q2 terms out there that I know of.  Kinda hard to come up with a perfect name for this shit.