Processing Forum

How to import a java library? (jBullet)

[4 Replies]
- 25-Sep-2012 06:03 AM
- Forum: Contributed Library Questions
Hi

I just tried to download the java jBullet library (http://jbullet.advel.cz/). Unfortunately I don't get what to do with the files since they are not structured as the usual Processing libraries. Is there anyone who can tell me how and where to place the files correctly?

VerletPhysics: addForce != addVelocity?

[1 Reply]
- 20-Jan-2012 06:09 AM
- Forum: Contributed Library Questions
Hi

I was wondering what the difference is between the methods 'addForce' and 'addVelocity' in the VerletParticle class?

Seems to do the same, or?
2. import toxi.geom.*;
3. import toxi.physics2d.*;
5. VerletPhysics2D physics;
6. VerletParticle2D pForce, pVelocity;
8. void setup(){
9. size(600,600);
10. noStroke();
11. fill(0);
12. smooth();
13. physics = new VerletPhysics2D();
14. physics.setDrag( 0.01f );
15. physics.setWorldBounds(new Rect(0,0, width, height));
16. pForce = new VerletParticle2D(300,300);
17. pVelocity = new VerletParticle2D(300,300);
18. pForce.addForce(new Vec2D(1,1));
19. pVelocity.addVelocity(new Vec2D(-1,1));
20. physics.addParticle(pForce);
21. physics.addParticle(pVelocity);
23. }
25. void draw(){
26. background(255);
27. physics.update();
28. ellipse(pForce.x, pForce.y, 5, 5);
29. ellipse(pVelocity.x, pVelocity.y, 5, 5);
30. }

VerletPhysics + randomSeed() (Toxiclibs)

[2 Replies]
- 04-Jan-2012 01:39 AM
- Forum: Contributed Library Questions
Hi

I was wondering if anybody knows if the VerletPhysics lib uses some kind of randomness that is unaffected by processings own randomSeed(int x) command?

I am testing a program and keep getting slightly different oucomes eventhough I use randomSeed?

best

Jacob

Out of memory error - unaffected by increasing available memory?

[2 Replies]
- 31-Aug-2011 02:04 AM
- Forum: Integration and Hardware
Hi

I am running a sketch in which a number of movie sequences is used to manipulate a 3D structure in OpenGL. After running for a while I get this error:

#
# A fatal error has been detected by the Java Runtime Environment:
#
# java.lang.OutOfMemoryError: requested 1920000 bytes for jint in C:\BUILD_AREA\jdk6_24\hotspot\src\share\vm\prims\jni.cpp. Out of swap space?
#
# Internal Error (allocation.inline.hpp:39), pid=5772, tid=4564
# Error: jint in C:\BUILD_AREA\jdk6_24\hotspot\src\share\vm\prims\jni.cpp
#
# JRE version: 6.0_24-b07
# Java VM: Java HotSpot(TM) Client VM (19.1-b02 mixed mode windows-x86 )
java.lang.OutOfMemoryError
java.lang.OutOfMemoryError

I have tried to increase the maximum available memory, but it does not seem to help? Rather, when I increase it, it crashes earlier?

Any ideas?

Shape of shared area

[1 Reply]
- 08-Apr-2011 05:56 AM
- Forum: Programming Questions
I am trying to figure out how to calculate the corner points of the shared area between two four sided shapes. That is, I want to be able to draw the shape of the area they have in common and hide the originals.

For example the two shapes in the attached sketch...

Up until now I have only been able to come up with overly complicated ideas and I am sure that there must be a simple mathematical way of doing it.
Any help will be greatly appreciated!
1. float[] xA = {50,285,275,45};
  float[] yA = {50,45,260,250};
  float[] xB = {90,255,345,95};
  float[] yB = {150,140,380,350};
  
  void setup(){
  size(400,400);
  stroke(255);
  noFill();
  }
  
  void draw(){
  background(0);
  beginShape();
      vertex(xA[0],yA[0]);
      vertex(xA[1],yA[1]);
      vertex(xA[2],yA[2]);
      vertex(xA[3],yA[3]);
  endShape(CLOSE);
  beginShape();
      vertex(xB[0],yB[0]);
      vertex(xB[1],yB[1]);
      vertex(xB[2],yB[2]);
      vertex(xB[3],yB[3]);
  endShape(CLOSE);
  
  
  }

Bending with particle/springs?

[2 Replies]
- 11-Mar-2011 06:43 AM
- Forum: Contributed Library Questions
I am trying to use the Traer physics library for simulating the behaviour of a bending stick. That is, a stick which is fixed in one end and has a direction (e.g. along the x-axis) that then starts to bend with gravity.

I had the idea that, additional to springs between neighbouring particles, I could achieve the bending effect by having a spring between every particle and the particle after the neighbour as well. Does not seem to work though?

I have attached the non-working code below.
Any ideas would be greatly appreciated!
1. //traer test simple
  import traer.physics.*;
  
  ParticleSystem physics;
  Particle[] particles;
  
  int TOTAL = 20; //total amount of particles
  int SCALE = 20; //distance between particles
  
  float SPRING_STRENGTH = 0.2;
  float SPRING_DAMPING = 0.1;
  
  void setup(){
  size(500,500);
  stroke(255);
  
  physics = new ParticleSystem(0.1, 0.01);
  particles = new Particle[TOTAL];
  
  for (int i = 0; i < TOTAL; i++){
      particles[i] = physics.makeParticle(.3, i * SCALE + 50, 50, 0.0);
      if(i!=0)    physics.makeSpring(particles[i-1], particles[i], SPRING_STRENGTH, SPRING_DAMPING, SCALE);
      if(i > 2)    physics.makeSpring(particles[i-2], particles[i], SPRING_STRENGTH*2, SPRING_DAMPING, SCALE*2);
  
      if(i < 2) particles[i].makeFixed();
  }
  }
  
  void draw(){
  background(0);
  physics.tick();
  for (int i = 0; i < TOTAL-1; i++){
      line(particles[i].position().x(), particles[i].position().y(), particles[i+1].position().x(), particles[i+1].position().y());
  }
  }

rotating a 2D array

[1 Reply]
- 20-Jan-2011 12:27 AM
- Forum: Programming Questions
Hi

Does a simple way of rotating the components of a 2D array exist?

Like taking this array:

int[][] original = {{ 0, 1, 0 },
                        { 1, 0, 1 },
                        { 0, 0, 0 }};

... and changing it to this:

int[][] cw90     = {{ 0, 1, 0 },
                         { 0, 0, 1 },
                     { 0, 1, 0 }};

DXF export and normal direction

[4 Replies]
- 19-Dec-2010 02:21 PM
- Forum: Contributed Library Questions
When exporting a dxf to Rhino I noticed that drawing one triangle counter clockwise and another clockwise does not make any difference regarding the direction of their normals. Like this:

import processing.dxf.*;

void setup(){
size(500,500, P3D);
}

void draw(){
beginRaw(DXF, "output.dxf");

beginShape();
vertex(0,0,0);
vertex(100,100,-10);
vertex(0,100,0);
endShape(CLOSE);

beginShape();
vertex(100,0,0);
vertex(100,100,0);
vertex(200,100,-10);
endShape(CLOSE);

endRaw();
exit();
}

Any way to get control over the normals? Another lib maybe? (I am trying to draw something for a 3D printer)

Increasing the frameRate when updating pixels

[1 Reply]
- 29-Nov-2010 05:46 AM
- Forum: Programming Questions
Hi

I was writing something like this for a larger sketch and wondered if there is a way to increase the framerate? Is there a better way to recalculate and update all pixels?
1. PGraphics pg;
  
  void setup(){
  size(900,450);
  noFill();
  pg = createGraphics(width, height, P2D);
  }
  
  void draw(){
  
  float sinFactor = width/(mouseX+1);
  float cosFactor = height/(mouseY+1);
  
  background(0);
  pg.loadPixels();
  for(int i = 0; i < width; i++){
      for(int j = 0; j < height; j++){
        color p = color( ( 127.5 * sin(radians(j)*sinFactor) * cos(radians(i)*cosFactor) ) + 127.5 );
        pg.pixels[j*width+i] = p;
      }
  }
  pg.updatePixels();
  
  image(pg,0,0);
  
  println(frameRate);
  }

Fluid Simulation

[3 Replies]
- 15-Oct-2010 03:10 AM
- Forum: Programming Questions
Hi

I have been trying (as probably many others before me) to translate Jos Stam’s Navier-Stokes solver ( http://www.dgp.toronto.edu/people/stam/reality/Research/pdf/GDC03.pdf) into Processing. I have managed to produce something that almost looks right, but not quite. It seems that the force field dies out after a short time, and I do not really understand the theory well enough to counteract this. I have a feeling that it might have something to do with the parameters that I pass into the system?

I am posting the entire code below (it is a bit much I guess, but the problem could be in many places). It’s visualizing the forces and the “dye”, which is distributed with the mouse.
Hope somebody has written a similar thing and I will be very happy if you are able to point out my mistake(s).
1. //Fluid Dynamics 2D
  
  FluidBox fSim;
  
  void setup(){
  size(500,500);
  noStroke();
  fill(255);
  fSim = new FluidBox(126, 10, .00001, 111.01);
  }
  
  void draw(){
  background(0);
  fSim.simulate();
  }
  
  class FluidBox{
  
  int       N;
  float     diffusion;
  float     dt;
  float     visc;
  float[][] u, v;
  float[][] u_prv, v_prv;
  float[][] dens, dens_prv;
  
  FluidBox(int dim, float diff, float time, float vs){
  N         = dim;
  dt        = time;
  diffusion = diff;
  visc      = vs;
  
  u        = new float[N+2][N+2];
  v        = new float[N+2][N+2];
  u_prv    = new float[N+2][N+2];
  v_prv    = new float[N+2][N+2];
  dens     = new float[N+2][N+2];
  dens_prv = new float[N+2][N+2];
  
  init();
  }
  
  //_____________________INITIALIZING FORCES_______________________________
  void init() {
  
      float xoff = 0;
      for (int i = 0; i < N; i++) {
        float yoff = 0;
        for (int j = 0; j < N; j++) {
          float theta = map(noise(xoff,yoff),0,1,0,TWO_PI*2);
          u[i][j] = cos(theta)*1500;
          v[i][j] = sin(theta)*1500;
          u_prv[i][j] = cos(theta)*1500;
          v_prv[i][j] = sin(theta)*1500;
          dens[i][j] = 0;
          dens_prv[i][j] = 0;
  
          yoff += 0.1;
        }
        xoff += 0.1;
      }
  }
  
  //_____________________SIMULATION_______________________________
  void simulate(){
      vel_step (N, u, v, u_prv, v_prv, 1, dt);
      dens_step(N, dens, dens_prv, u, v, diffusion, dt);
      fluid_draw();
  }
  
  void dens_step ( int N, float[][] x, float[][] x0, float[][] u, float[][] v, float diff, float dt){
  
      if(mousePressed && (mouseButton == LEFT)) {
        dens[(int) mouseX/4][(int) mouseY/4] = 100;
      }
  
      add_source(x, x0, dt);
      SWAP(x0, x);
      diffuse(N, 0, x, x0, diff, dt);
      SWAP(x0, x);
      advect(N, 0, x, x0, u, v, dt);
  
  }
  
  void vel_step (int N, float[][] u, float[][] v, float[][] u0, float[][] v0, float visc, float dt){
  
      add_source(u, u0, dt);
      add_source(v, v0, dt);
      SWAP(u0, u);
      diffuse(N, 1, u, u0, visc, dt);
      SWAP(v0, v);
      diffuse(N, 2, v, v0, visc, dt);
      project(N, u, v, u0, v0);
      SWAP(u0, u); SWAP(v0, v);
      advect(N, 1, u, u0, u0, v0, dt);
      advect(N, 1, v, v0, u0, v0, dt);
      project(N, u, v, u0, v0);
  }
  
  void diffuse (int N, int b, float[][] x, float[][] x0, float diff, float dt){
      int i,j,k;
      float a = dt*diff*N*N;
      for( k=0 ; k<5 ; k++) { //why 5 iterations?
        for( i=1 ; i<=N ; i++) {
          for( j=1 ; j<=N ; j++) {
            x[i][j] = (x0[i][j] + a*(x[i-1][j] + x[i+1][j]+x[i][j-1]+x[i][j+1]))/(1+4*a);
          }
        }
        set_bnd( N, b, x );
      }
  }
  
  void advect(int N, int b, float[][] d, float[][] d0, float[][] u, float[][] v, float dt){
      int i, j, i0, j0, i1, j1;
      float x, y, s0, t0, s1, t1, dt0;
  
      dt0 = dt*N;
      for( i=1 ; i<=N ; i++){
        for( j=1 ; j<=N ; j++){
          x = i-dt0*u[i][j]; y = j-dt0*v[i][j];
          if (x<0.5) x=0.5; if (x>N+0.5) x=N+ 0.5; i0=(int)x; i1=i0+1;
          if (y<0.5) y=0.5; if (y>N+0.5) y=N+ 0.5; j0=(int)y; j1=j0+1;
          s1 = x-i0; s0 = 1-s1; t1 = y-j0; t0 = 1-t1;
          d[i][j] = s0*(t0*d0[i0][j0]+t1*d0[i0][j1])+
          s1*(t0*d0[i1][j0]+t1*d0[i1][j1]);
        }
      }
      set_bnd( N, b, d );
  }
  
  void set_bnd ( int N, int b, float[][] x){
      int i;
      //reversing forces at edges
      for( i=1 ; i <= N ; i++) {
        x[ 0 ][ i ] = b==1 ? -x[1][i] : x[1][i];
        x[N+1][ i ] = b==1 ? -x[N][i] : x[N][i];
        x[ i ][ 0 ] = b==2 ? -x[i][1] : x[i][1];
        x[ i ][N+1] = b==2 ? -x[i][N] : x[i][N];
      }
      //corners
      x[ 0 ][ 0 ] = 0.5*(x[ 1 ][ 0 ]+x[ 0 ][ 1 ]);
      x[ 0 ][N+1] = 0.5*(x[ 1 ][N+1]+x[ 0 ][ N ]);
      x[N+1][ 0 ] = 0.5*(x[ N ][ 0 ]+x[N+1][ 1 ]);
      x[N+1][N+1] = 0.5*(x[ N ][N+1]+x[N+1][ N ]);
  }
  
  void add_source(float[][] x, float[][] s, double dt) {
          int i, j;
          for (i = 0; i < N; i++){
            for (j = 0; j < N; j++){
              x[i][j] += dt * s[i][j];
            }
          }
  }
  
  void project (int N, float[][] u, float[][] v, float[][] p, float[][] dv){
  
      int i, j, k;
      float h; h = 1.0/N;
  
      for ( i=1 ; i<=N ; i++ ) {
        for ( j=1 ; j<=N ; j++ ) {
          dv[i][j] = -0.5*h*(u[i+1][j]-u[i-1][j]+
          v[i][j+1]-v[i][j-1]);
          p[i][j] = 0;
        }
      }
  
      set_bnd ( N, 0, dv ); set_bnd ( N, 0, p );
      for ( k=0 ; k<20 ; k++ ) {
        for ( i=1 ; i<=N ; i++ ) {
          for ( j=1 ; j<=N ; j++ ) {
            p[i][ j ] = (dv[i][j]+p[i-1][j]+p[i+1][j]+
            p[i][j-1]+p[i][j+1])/4;
          }
        }
        set_bnd ( N, 0, p );
      }
        for ( i=1 ; i<=N ; i++ ) {
          for ( j=1 ; j<=N ; j++ ) {
            u[i][j] -= 0.5*(p[i+1][ j ]-p[i-1][ j ])/h;
            v[i][j] -= 0.5*(p[ i ][j+1]-p[ i ][j-1])/h;
          }
        }
        set_bnd ( N, 1, u ); set_bnd ( N, 2, v );
  }
  
  void SWAP(float[][] x0, float[][] x) {
          float[][] tmp = new float[N+2][N+2];
          arraycopy(x0, tmp);
          arraycopy(x, x0);
          arraycopy(tmp, x);
  }
  
  void fluid_draw(){
      int i, j;
  
      for( i=0 ; i<=N ; i++){
        for( j=0 ; j<=N ; j++){
          stroke(255,0,0);
          line(i*4, j*4, i*4+u[i][j]*.006, j*4-v[i][j]*.006);
          noStroke();
          fill(map(dens[i][j],0,.75,150,255),map(dens[i][j],0,.75,0,255), map(dens[i][j],0,.75,255,100));
          ellipse(i*4, j*4, constrain(dens[i][j]*3,2,10), constrain(dens[i][j]*3,2,10));
        }
      }
  }
  }

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