video

example of using behaviors for Graphics

I made a master to demonstrate how to create some of the graphic effects (used by the flight404 project) using behaviors.

please update your code from the repository, and go to the initialize() mathod of GraphicEffects.java in the master package.

within this methos is a demonstration of how to subscribe behaviors to wetObjects. There is no limit to the number of behaviors you can subscribe, try to understand how they are used, and write your own wetObjects and behaviors.



For those of you don't code, I make some screen shots of graphic affects that we have right now, I would suggest to make a wish list, stating any geometric forms, or graphics effects or dynamics that you wish to create.

Interactive Particle Stuff UCLA

http://bodytag.org/fluid_bodies/

Get the Code(updated)!!!

This guide is only for people who use Eclipse. For those of you who use something else, you will have to find directions of how to add a cvs repository to your workspace. If you need help, just email me. I've tested this on a mac (leopard), windows (vista), ubuntu (gutsy gibbon).

1. Make sure you have Eclipse installed (http://www.eclipse.org)
2. Make sure you have at least JDK 5.0 installed on your computer. (http://java.sun.com/javase/)
3. In Eclipse, File->Import... Then choose CVS->Projects from CVS. Click next.
4. A screen may show up that lets you choose to create a new repository or use an existing one if you have one already. Choose to create a new one. Click next.
5. Fill in the form with the following information:

host: fathead.mit.edu
Repository Path: /school
User: <athena-user-name>
Password: <athena-user-name> (this can be changed if you want it to, just let me know)
Connection type: pserver
Use Default port should be selected

Once filled in, click next.

6. Select "Use an existing module". Select picasso and select finish.

You should now have a project in your workspace called picasso There should be no errors in the project but maybe some warnings.

Now you can run the application. I like using the view Package Explorer (Window->Show View->Package Explorer). Navigate to active->application->RunMe. Right click it and select Run As->Java Application.

There should be a pop up window that asks you use which? and num windows. If not, then something went wrong, so email me.

Another note. Si and I will be working on the core of the system and will be updating the system as the term continues. So because of this, you're going to want to "update" the code on your computer to reflect our changes as well as "commit" your changes to be reflected on other peoples computers. When you are done working on something and are ready to put it on the system, do the following:

1. In the Package Explorer view, right click on the project (picasso)->Team->Update. This should update your code on your computer with the changes that others have made.

To "commit" your code so that it is reflected on the server:
1. In the Package Explorer view, right click on what you want to add to the server->Team->Commit. Follow the instructions. This should add the changes you made to the server.

Anyways, enjoy. If you have any problems getting it running, let me know and I'll try to help you out. Si and I will be posting tutorials as we get them written.
Important Notice:
Please do not change the files in the "dev" folder. These are changed daily by Si and I. Most of everyones contribution will be in the "active" folder.

B005-Change the Look

Tutorial on changing only appearance of a wetObject.
link:
http://www.mit.edu/~seah/changeLook.html

Neat processing tricks...and some ideas

flight404

This is a blog of the videos posted by Kaustuv.  I've been reading through them and have come up with some ideas we can implement.

To create the beat ones, he would play the song through and manually hit the punches (assigning keys to different percussion instruments such as bass drum, snare, etc.).  We can do this in real time and have the audience try to use a wii to play the beat while the music is playing.  Every button is an instrument and each instrument would be certain visual effects (behaviors) in the system.

Also, another point I want to make about graphics and cool effects is textures.  You can use textures(images) to make the graphics in the system.  Instead of coding an awesome fire particle, you would use a texture that looks like an awesome fire particle in the system along with smaller graphics functions.  So for those visual artists in you, this is your calling.

Robert Hodgin - Magnetic Ink (Processing again!)

Magnetic Ink, Process video from flight404 on Vimeo.

Robert Hodgin - Solar with lyrics (Processing with Sonia)

Solar, with lyrics. from flight404 on Vimeo.

cellular soundscape!

B004-Writing a Behavior

the e blog does read HTML very well and destroys all my line format, so please go to the following link:
http://www.mit.edu/~seah/writingBehavior.html

B003-Making your first WetObject and give it a behavior

This tutorial lets you get started with wetObject and behaviors.

After this tutorial you should know:

1. How to create WetObject

2. How to alter the behavior of a wetObject by assigning behavior scripts to it

Before you continue any further, I assume you have read Mikey’s email
instruction about obtaining the code, and have downloaded the code from the
CVS repository. Also I assume you have used eclipse and java.

If you run the active_picaso project, you should see a popup window allows
you to choose different master. We will use “levitation” master
for this tutorial.

When you run with “levitation” selected as option, you should see
two boxes, one circulates around and the other looks at the moving box as it
circulates.

We are now going to look at the code of these.

1. Go to a package named “masters” and find levitation

2. Go to the method called “initialize()”

Within this method you are going to create a new box, and let this new box
also look at the circulating box.

1. create a new wetObject

(WetObject by default draws itself as a box, in this tutorial I am not going
to show how to change the appearance of wetObjects. Lets do that in another
tutorial.)

Within this method, At the end of all existing lines, add the following:

// This line creates a new WetObject instance called
o3.

WetObject o3=new WetObject();

//now add this to the scene

//the create() method adds any

//WetObjects or childrens of Wetobject into our world

o3.create();

//set the position of this wetObject

//by default it creates at (0,0,0)

o3.setPos(20,20,20);

if you run the application now, you should see three boxes instead of two.
If so, you have successfully created a wetObject

2. Make the new box look at the circulating box

We have make some simple behaviors in the package called “behaviors”.
If you are writing behaviors later on, you will be adding them to the behaviors
package.

Now we are going to assign one of the behaviors to the new box

Add this line:

o3.subscribe(new LookAtWetObject(o3,o));

if you run the application again, the new box will have a behavior which looks
at the circulating box. Don’t worry about what the arguments are at this
point.

The idea is, you are going to write different behaviors, we can subscribe multiple
behaviors to an object using the subscribe() method. And those behaviors are
what provides us different visual effects and particle dynamics

When you run you application, If you see three boxes, one circulates around
and the other two looks at it, you have completed this tutorial.

The next one is “Understand the Core of WetObject and Write a Behavior”

B002-A brief explanation of the system

Our system has relies on using different behaviors on particles to create visual affect

mostly everyone is going to contribute to behaviors for wetObjects. we will go over this in more detail tutorial, here is a overview of the tree kinds of scripts you will be writting.

dowload ppt from here:http://www.mit.edu/~seah/WetExplain.ppt

B001-moving things in 3D using the Vector3F class

Why do you need this tutorial?

This tutorial tells you how to move things in 3d using some basic vector math,
and introduce you to our Vector3F class. You can skip to the Vecto3F documentation
if you know vector math.

This tutorial includes:

A Concepts:

A1. What is vector?

A2. Normalizing vectors

A3. Adding vectors

A4. Subtracting vectors

A5. Scaling vectors

A6. Dot product

A7. Cross products

B HowTo:

B1. How to move a point from point A to point B?

B2. How to animate a point moving from A to B in N steps?

B3. How to find a normal of a plane?

B4. How to find a line perpendicular to a given line?

B5. How to scale a group of point with a base point?

---

A1. What is vector?

Vector

"vector, is a geometric object which has both
a magnitude and a direction"(Wikipedia)

A vector can be seen as point in space, it can be represented by three numeric
values, such as (x,y,z), that indicated the distance from this point to the
origin(0,0,0)

in our Vector3F class you can create a vector by calling:

Vector3F myPoint=new Vector3F(3,5,10);

this line creates a vector called myPoint at the
location x=3, y=5,z=10.

Direction

the direction from 0,0,0 to the point(x,y,z) is the direction of the vector.

Magnitude
the magnitude of this vector is the distance between (0,0,0) and (x,yz)
in our Vector3F class, you can find the magnitude of the vector by calling
the mag() method. For example:

//v is a vector

Vector3F v;

//get magnitude of v

Float magnitude = v.mag();

A2. Normalizing vectors

Normalizing a vector is to make the magnitude of a vector equals 1. This is
usually when we do different kinds of calculations such as scaling a vector
to a desire length or calculate angles

In out Vector3F class, you can use the normalize() method

Vector3F v=new vecto3F(0,5,0);

v.normalize();

the result is, v become (0,1,0);

A3. Adding vector

is best illustrated in this diagram

(hyperphysics)

in our Vector3F class, there are two ways to do this.

Assume we have two instances vector3F called A and B.

Vector3F A=new Vector(1,2,3);

Vector3F B=new Vector(2,3,4);

Case 1, we want to add B to A, so that

A=A+B

In this case, we can do:

A.add(B);

The result is A becomes (3,4,7)

Case 2, we want do want to change the values of A and B, we want to add them
to a new Vector called C such as C=A+B

In this case we do

Vector3F C=Vector3F.add(A,B);

The result is A and B are un changed, but C becomes (3,4,7)

See documentation for Vector3F.add(Vector3F) and
vector3F.add(Vector3F,Vector3F) for detail

A4. Subtracting vectors

vector subtraction can be described by this diagram:

(pearMath)

Simmular to addition, there are two ways to do subtractions:

Assume we have two instances vector3F called A and B.

Vector3F A=new Vector(1,2,3);

Vector3F B=new Vector(2,3,4);

Case 1, we want to subtract B from A, so that

A=A-B

In this case, we can do:

A.sub(B);

The result is A becomes (-1,-1,-1)

Case 2, we want do want to change the values of A and B, we want to subtract
them to a new Vector called C such that C=A-B

In this case we do

Vector3F C=Vector3F.subtract(A,B);

The result is A and B are un changed, but C becomes (-1,-1,-1)

See documentation for Vector3F.sub(Vector3F) and
vector3F.subtract(Vector3F,Vector3F) for detail

A5. Scaling vectors

scale a vector is to scale the magnitude of a vector by a number. in Vecto3F,
we can do this by:

Vector v=new Vector(0,3,0);

v.scale(4);

the result is v become (0,12,0)



A6. Dot product

"dot product, also known as the scalar product, is
an operation which takes two vectors over the real numbers R and returns a real-valued
scalar quantity. It is the standard inner product of the Euclidean space."(see
wikipedia for more detail)

you may not need to use this, but the way to do it in Vector3F is:

First assume we have two vectors as such:

Vector3F A=new Vector(1,2,3);

Vector3F B=new Vector(2,3,4);

Case 1: A=A dot B

A.dot(B);

Case2: C=A dot B

Vector3F C=Vector3F.dot(A,B)

A7. Cross products

"the cross product is a binary operation on two
vectors in a three-dimensional Euclidean space that results in another vector
which is perpendicular to the two input vectors."(see
wikipedia for more detail)

You may need to do a cross product very often when you a scripting sptial transformations.
In Vector3F, there are two ways to do it. First assume we have two vectors as
such:

Vector3F A=new Vector(1,2,3);

Vector3F B=new Vector(2,3,4);

Case 1: A=A cross B

A.cross(B);

Case2: C=A cross B

Vector3F C=Vector3F.cross(A,B)

---

B1. How to move a point from point A to point B?

Moving a point from A to B is changing the x,y,z value of point A into corresponding
values from point B.

Here is an example using Vector3F.

let say PointA and PointB are both instances of Vector3F.

PointA.set(PointB)

this line makes each of the x,y,z value of PointA equals to each of the x,y,z
values of PointB.

see Vector3F.set(Vector3F) method

B2. How to animate a point moving in space?

If you wan to animate a point moving from PointA to PointB in the duration of
10 frames, here are the things you may want to do:

1. find the distance between PointA and PointB

2. Divide the distance by 10 to get the length that the point wants to move
each frame

3. Using the move direction and move length to find the vector that indicates
the change of position in a single frame.

4. move the point.

here is the Vector3F version:

Assume the Point that is being animate is an instance of Vector3F called myPoint,
and Point A and B are also instance of Vector3F called PointA and PointB.

Initially myPoint is at PointA, we want to move it to PointB in 10 steps

//1. find the distance D between PointA and PointB

double distance = PointA.distanceTo(PointB);

//2. Divide the distance by 10

//to get the distance that the point

//wants to move each frame

double moveDist=distance/10;

//3. first fine the direction that the point

//moves towards

Vector3F direction=Vector3F.subtract(PointB, PointA);

//normalize the vector

direction.normalize();

//scale the direction vector with the distance you want
to move

direction.scale(moveDist);

//4. move the point in a single frame

myPoint.add(direction);

Because the behaviors are being called every frame, therefore you only have
script the movement in a single frame, and this action will be carried out every
frame automatically by the system. So how do you make it stop moving? Simply
check to see if myPoint has moved to PointB. The code is:

if ( myPoint.equals(PointB)) //than stop moving

However, it's better to put tolerance into our code to avoid bugs, so we change
above condition to :

if (myPoint.distanceTo(PointB)<0.001) //then stop

The "0.001" in the code is the tolerance. No need to explain this
line right?

We can look at the entire animation structure as:

//if the myPoint is not at PointB

//( pay attention to the negate sign "!" in the logical expression

if( ! myPoint.distanceTo(PointB)<0.001)>

//move the point one step

//put your code here:

double distance = PointA.distanceTo(PointB);

double moveDist=distance/10;

Vector3F direction=Vector3F.subtract(PointB, PointA);

direction.normalize();

direction.scale(moveDist);

myPoint.add(direction);

}

this illustration shows a movement in constant speed, however there are many
ways to move a point from A to B, such as:

if( ! myPoint.distanceTo(PointB)>0.001)

{

double distance = myPoint.distanceTo(PointB);

double moveDist=distance/10;

Vector3F direction=Vector3F.subtract(PointB, myPoint);

direction.normalize();

direction.scale(moveDist);

myPoint.add(direction);

}

In this case, the movement will slow down as it get closer to PointB exponentially,
and it will take forever to complete the movement if you don't set a tolerance.

you can come up with your own way of animating movements.

B3. How to find a normal of a plane?

The normal to plane is the cross product of two vectors on the plane

You make want to take note on the following scenarios:

1. when the plane is defined by 3 points:

let say there are point A,B,C on the plane, the math is:

normal=(A-B) cross (C-B)

the Vector3F version is:

Assume point A,B,C are expressed as instances of Vector3F.

Vector3F normal= Vector3F.cross( Vector3F.subtract(A,B),
Vector3F.subtract(C,B) ) ;

I know is not very readable, so you can also write it as:

// let value1=A-B

Vector3F value1=Vector3F.subtract(A,B);

//let value 2=C-B

Vector3F value2=Vector3F.subtract(C,B);

//let normal = value1 cross value2

Vector3F normal=Vector3F.cross(value1, value2);

let's just consider this case for the time being

B4. How to find a line perpendicular to a given line?

A normal of a plane is always perpendicular to any lines on that plane. Knowing
this will help us find lines perpendicular to a given line.

For example we want to find a line perpendicular to line A-B, and line A-B is
expressed as two endpoints A and B. A and B are instances of Vector3F.

We first assume line A-B exist in an arbitrary plane.

remember plane can be defined by three points, so we will make an arbitrary
point C.

C can be any thing, but if you want to have more control over where C is relative
to A, you can create C using an offset

//this offset tells you C is right above B at one unit.

Vector3F offset=new Vecto3F(0,0,1);

//let C=B+offset

Vector3F C=Vector3F.add(B, new Vector3F(0,0,1));

now you have a plane, the name thing is to find the normal.

Vector3F value1=Vector3F.subtract(A,B)

Vector3F value2=Vector3F.subtract(C,B)

Vector3F normal=Vector3F.cross(value1, value2);

this normal is perpendicular to lineA-B, you can move it anywhere like:

Vector3F D = Vector3F.add(normal,B)

this line will create a point D where line D-B is perpendicular to line A-B

B5. How to scale a group of point with a base point?

If we have to scale a group of points base on a given base point that is not
(0,0,0), there are basically three steps:

1. we have to translate all points to new position so that are based on (0,0,0)

2. scale all the points

3. undo the translate we have done in part 1

Vector3F version is:

Assume the base Point is a Vector3F called basePoint.

We want to scale 3 times in size

Foreach point P(which is a Vector3F) in our points:

Vector3F offset=Vector3F(basePoint-new Vector3F(0,0,0));

//translate to a 0,0,0 base coordinate system

P.sub(offset);

//scale the vector

P.scale(3);

//undo the translation

P.add(offset);