2011-04-23

Second Life creativity: Bald Eagle and USA (satire)

eagle usa flag 1-s

Bald eagle holding a machine gun with US flag. The eagle avatar is made by An Ballinger, and the nest, machine gun, flag, is a creativity by Kristian Kit.

2011-04-22

2011-04-21

What's PunkBuster & What's System Requirements Lab?

What's PunkBuster & What's System Requirements Lab?

Habitually i clean my computer. Here's my installed software as a list from 〔Control Panel\Programs and Features〕. installed_programs_mswin_2011-04-19.txt

Here's software i'm deleting. When you download games, they often comes with a bunch of garbage.

  • PunkBuster Buster Services Even Balance, Inc. 2009-11-12 0.988 • A anti-cheat software
  • System Requirements Lab 2009-07-30 0.38 MB • game requirement checker.

I use CClean to generate the list. It is a great too. See: List of Great Windows Software and Windows Starting Too Slow? Disable Windows Startup Apps with msconfig.

2011-04-20

Second Life Problems: llSitTarget as Teleporter

Perm url with updates: http://xahlee.org/sl/lsl_llSitTarget.html

Second Life Problems: llSitTarget as Teleporter

Get your Xah Particle Maker today!

Xah Lee, 2011-04-20

Second Life is The Worst Software Possible

Second Life is the worst software possible since 2000s. I can't start to list the problems. The whole design, every aspect, sucks major. Crashes every few hours, for the past 4 years.

Yesterday i did a project of scripting teleporters for a guy. It's quite ridiculous, that in-sim teleporters are done by using a sit hack using “llSitTarget”. Here's a sample script:

// 2011-04-20
// sample simple in-sim teleporter

vector targetPos = <96, 199, 31>; //The target location

tp_setup()
{
    vector sitOffset;
    
    sitOffset = (targetPos- llGetPos());
    llSitTarget(sitOffset, ZERO_ROTATION);
    llSetSitText("Teleport");
}

default
{
    state_entry()
    {
        tp_setup();
    }
    
    on_rez(integer startup_param)
    {
        tp_setup();
    }
    
    changed(integer change)
    {
        llUnSit(llAvatarOnSitTarget());
        tp_setup();
    }    
}

There are quite a few ridiculous things going on.

Teleport are done by setting up a object's sit behavior with a offset. The typical usage is like this: avatar sits on a object, due to the offset, he actually is sitting somewher far away, then, once sl detected the sit as a change, the script bumps off the avatar from sitting. The final effect from the user's point of view is teleportation!

Can't be more bizarre than this. SL is like this, all over. Scripting, building, just about every aspect. The most idiotic possible, and with bugs everywhere.

Geometry: Ellipses, Linkages, and Solids of Constant Width

Perm url with updates: http://xahlee.org/math/solids_of_constant_width.html

Geometry: Ellipses, Linkages, and Solids of Constant Width

Xah Lee, 2011-04-20

Various very interesting mathematical objects.

In particular, it shows various shapes based on properties of Ellipse, and various linkages. Peaucellier Linkage, and Hart's Linkage, based on properties of Geometric Inversion. (see: Geometric Inversion). What's interesting about these linkages is that they are mechanical means to convert between circular motion and straight line motion, important in the industrial revolution era. (think of the linkage on the wheels of steam-powered trains) The video alse feature curves and solids of constant width. Imagine, you can roll a book on top of several marbles. The marbles are spheres. However, there are also shapes that's not sphere but still lets you roll the book smoothly.

Their website howround.com features these objects in more detail, also with a book How Round Is Your Circle?(2011) John Bryant, Chris Sangwin. amazon

Drilling a Square Hole

One particul thing i found very interesting in the video is that they showed a drill that is designed to drill a square hole.

square drill

Square Drill. See: Source web.mat.bham.ac.uk

Train's Wheel Linkage

Walschaerts motion

Walschaerts motion. See Steam locomotive. Source en.wikipedia.org

See also: Linkage (mechanical).

2011-04-17

emacs: ErgoEmacs keybinding version 5.3.9 released

New version of ErgoEmacs keybinding is out, at 5.3.9 (2011-04-17). Major changes since 5.3.7 (2010-11-15):

  • Added a hotkey 【Ctrl+Shift+t】 for open-last-closed in ErgoEmacs keybinding package. This key follows browser convention. But won't work in Terminal...
  • If you load ErgoEmacs keybinding files before turning on cua-mode, some keys with Shift will also highlight text. Fixed.
  • Also fixed a minor bug when used together with auto-complete-mode.

See _HISTORY.txt for full detail.

Download at: ErgoEmacs Keybinding.