My natural selection module works pretty well but one concern was how to make it a bit more interesting. One obviously way to do that would be to make Cami's that move so that they are harder to spot and catch.
So since I really don't know a whole lot about making things move in Second Life, the first thing I did was develop a cami that will roam around randomly but stay in my land.
The strategy I developed builds on a function I had previously scripted for random movement of a prim:
//--------------------------------
vector newcoodinates(vector pos ,float pathlength, integer start)
{
integer icount;
float deltax;
float deltay;
vector temp;
float ground;
temp = llGetPos();
if (start = TRUE)
{
deltax = llFrand(pathlength)-pathlength/2;
deltay = llFrand(pathlength)-pathlength/2;
temp.x = temp.x + deltax;
temp.y = temp.y + deltay;
ground = llGround(<0.0,0.0,0.1>);
temp.z = ground;
if (llGetLandOwnerAt(temp) == llGetOwnerKey(llGetKey()))
{
return temp;
}
else {
return pos;
}
}
return temp;
}
//---------------------------------------------------
The idea is to take the prim's current position and update it with a "random" number between zero and some maximum path length. That's what this statement does in the one dimension:
deltax = llFrand(pathlength)-pathlength/2;
Since I want the cami's to hug the ground for the vertical dimension I use LSL's llGround function:
ground = llGround(<0.0,0.0,0.1>); the result is the vertical dimension.
One thing that flummoxed me for awhile was how to keep the cami in bounds. My original idea was to have the cami detect when it was on someone else's land and have it turn around and leave. But that turned out to be more difficult to script in a totally fool proof manner to this trigonometrically challenged scriptor. Besides, it seemed much better and nicer, to stop the cami from even entering someone's land in the first place:
So that's what this piece of code does:if (llGetLandOwnerAt(temp) == llGetOwnerKey(llGetKey()))
{
return temp;
}
else {
return pos;
}
The rest of the basic movement script is deceptively simple:
default
{
state_entry()
{
do {
newpos = newcoodinates(llGetPos() ,2,start);
llSetRot(llEuler2Rot(<0,0,-pi/2>)*llGetRot());
llLookAt(newpos,1,0);
llSetPos(newpos);
llStopLookAt();
}
while (start==TRUE);
}
}
The rotation functions are sort of trial and error on my part but the cami's end up with an interesting waddling motion, so I am pleased with that even if it wasn't quite what I wanted at first.
Deceptively simple because I also needed toggle that stops the cami's so I can catch them and for determining the cami genotypes and phenotypes. Fortunately my previous cami scripts are easily modified to to work with my cami movement script.
The result is Natural Selection the Predator version right now at:
http://slurl.com/secondlife/Carmine/123/151/135Just touch the light blue prim and 50 maddingly difficult to catch cami's will start swarming around:
The idea is to put yourself in the role of a predator selecting against one of the phenotypes. The phenotypes use my cami genetics scripts and it is possible to select against one of the phenotypes and eliminate the genes for that phenotype, but its harder than it looks.
This version will allow you to keep selecting until the the cami's derez at which point you must touch the blue prim again to rez the next generation of cami's using the ones you didn't get as the parent population. I may change this feature.
The main script in the cube again handles all the book keeping and generates a report tracking the allele frquencies when you touch it to rez the next generation.
By the way, when you touch one of the camis in your role as predators they explode red blood thanks to a little particle script...next will be sound effects.
So even if you don't know squat about population genetics or evolution, at least you get to blow up stuff. I guess there is a bit of adolescent even in the most prim and proper of us.
Oh if you visit, watch out for cami sharks.
This week I will be designing some suggested activities related to evolution using my cami system and also taking a few days for a trip to the Ozarks for springtime dogwood viewing, I hope.
Just down the road from my project is this collection of marvelous insects made with scupted prims...and they are flyable according to the menu options. But I guess you have to be the owner to fly them.
Been busy teaching in first life this summer but also with Second Life as well. In about 2 weeks I in my first life presence as Paul Decelles will be giving a presentation on doing simulations in Second Life to the SIDLIT conference in Kansas City. My topic is Scientific Simulations in Virtual Worlds and I will cover some of the stuff I did on my sabbatical, lots of which is on this blog, and also discuss alternative virtual world systems for doing simulations.
In Second Life there are often several ways to ummm build a cat. So it is easy to get stuck in one way of doing things. For instance, when I duplicate an object I always do it from the pie menu and had forgotten about the little shift and drag trick, which is actually a lot easier. Another example: our first homework assignment is to build a chair and while I have done some building had not built my on chairs-just quickly slapping things together not not being too concerned with the llSitTarget function.
Chromosome Build at JCCC site. This is part of the evolution unit being installed at the JCCC site. It currently includes the human chimp ideograms courtesy of ENSI. You can see two of my real simple viewers, the one on the left with some narrative and the one on the right with the human chimp chromosome ideograms.
As part of my evolution build I wanted to have an activity related to chromosomal rearrangements. We know these are important in evolution, some of the clearest examples are in our own evolutionary history. So I developed a series of human chromosomes similar to those over at Genome Island.
It's probably hard to see what's going on here. But the big white structure in the center represents huna chromsome 1, and the chimp chromsomes with regions of synteny for human chromosome 1 are shown to the left and right. Human chromosome one has synteny with most of chimp chromosome 1 with just a little region of synteny with chimp chromosome 2A and chimp chromosome 10.
This shows prophase, prometaphase, metaphase, anaphase and telophase. You can see me in the bottom of the picture. Each of the "cells" is 10m in diameter.
Speaking of collaborative activities, I also tweaked my predator natural selection module and installed it on my college land site. The module is packaged appropriately with a velociraptor texture so hopefully student predators will get in to the spirit of things.
Now that I have my drift and selection modules in hand, the next goal is to working on activities that can be fit around them. I know this is a bit backwards on the surface, but what I want to focus on in my evolution module is mainly the agents of evolution. These are basically:
To house the activities related to these agents, I have deviated from my photosynthesis and genetics design and come up with a series of open activity arenas. Each one will have a sensor driven script for tracking visitors, an simple activity rezzer of my own design, built into one of the corner posts. Rather than use my Carmine land, I am building the agents of evolution site at my College's island. The design challenge is to work with in a 281 prim limit.
Oh and my goal is to have this done by May 7th. At least now I can focus on design more rather than the arcanity of the LSL's llfrand function and other such issues. Plus I will have two radically different design approaches to compare, the module in a box approach of my photosynthesis and gentics builds versus my more open arena centered approach.
My natural selection module works pretty well but one concern was how to make it a bit more interesting. One obviously way to do that would be to make Cami's that move so that they are harder to spot and catch.
One thing that flummoxed me for awhile was how to keep the cami in bounds. My original idea was to have the cami detect when it was on someone else's land and have it turn around and leave. But that turned out to be more difficult to script in a totally fool proof manner to this trigonometrically challenged scriptor. Besides, it seemed much better and nicer, to stop the cami from even entering someone's land in the first place:
Well no, how about 30 Caminalcules after selection favoring a recessive allele for 8 generations. The natural selection module beta is finished and works very well. The basic strategy is to have the user or users act as visual predators removing camis from the population. The module might for instance be on a certain background where some cami phenotypes are real obvious while others are not.
So far I been working with my caminalcules in terms of genetics. But of course-and maybe someone ought to tell creationists about this-evolution and genetics are logically connected and evolution follows from genetics. So naturally I want to use my system to simulate the basic mechanisms of evolution.
Notice the pink and green phenotypes are becoming more common. The the genes related to the white caminalcules have apparently been eliminated. Since the genes related to the white photype are recessive the student might think (as did some geneticicts in the early 20th century)
Actually the picture shows the population after 14 generations since I wanted to make sure the other types were eliminated. This nicely shows that the effect of genetic drift is to reduce genetic variation in a population.
Not very different than the starting population from the previous run. But look what happens now! This is at generation 10. Note the large number of white caminalcules. Remember white is recessive.
Today Kira Cafe hosted a presentation by Nicole Yankelovich from Sun Microsystems about Wonderland, an environment for creating virtual worlds. Wonderland is quite different than Second Life in a number of respects. So I will briefly summarize my in world notes.
So much science in Second Life and so little time. But today I took a little side trip following Darwin's Voyage of the Beagle. This is a wonderful build and very appropriate for the 200th anniversary of Darwin's birth and the 150th anniversary of the publication of Origin of Species.
If you go, dress appropriately, my normal dress in SL is much too fancy and just to be safe I removed my Geisha hair attachment and skin and donned my Science Friday shirt.
There is lots of wildlife some of which are clues for the game and plenty of poisonous snakes which of course I think are cool. Here is a cobra. I don't recall Darwin mentioning cobras in Voyage, but I ought to check that. Needless to say good thing the SL health option was not on, else I would have died several times over from snake bites.
Of course there are the Galapagos tortoises, pretty much in scale. Here's one with Opuntia cactuses. The focus of the build goes beyond evolution and natural selection to include Darwin's hypotheses about coral reef formation and if you want you can even go diving.
By the way the interface includes a supply pack that provides you with a compass and journal. Both are lots of fun.
I suppose, now the creationists will follow suite and probably put up a Second Life Creation Museum. I wonder how they will show the intelligent designer. Oh I forget, you're not allowed to infer anything about the nature of said designer.
I really do need to blog more about some of the places and workshops I visit. One of my new places to visit is Kira Cafe sponsored by the Kira Institute. Kira Cafe is for discussion of science and more. As the institute's mission statement notes:
Continuing along with my Caminalcule genetics activity...
