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Topic: Global values (Read 413 times) |
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Charles Hinshaw
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Global values
« on: Jan 26th, 2004, 9:30pm » |
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Maybe someone can help here.
I need to access an array in my loop();
The array isn't global because the depth of the array isn't determined until half way through setup() -- (it is based on the number of pixels on the screen and on the values of those pixels.)
I did a search in this section, but nothing turned up.
Is there a way to get my array to be accessable inside of the loop? I would like to get it working so that I can figure out how badly I messed up the rest of the code...
Thanks,
Charles Hinshaw
direction + repertoire
[r]evolve, US
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Charles Hinshaw
Guest
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Re: Global values
« Reply #1 on: Jan 26th, 2004, 9:39pm » |
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This may help (or completely confuse people, as it is my first attempt at building something in processing) --
Basically, I need to access the array "p[]" inside of the loop(), BUT the array can't be be declared until I know the total number of particles to create.
Also, this is very slow... maybe because I am working with between 25,000 and 5,000,000 particles, depending on the depth of the images that I have used, but if anyone can give me some advice as to how to speed it up, that would be GREAT. Thanks.
// User Control Variables
String imagename = "dust.jpg"; // Initial Image File in DATA Directory
// ------------------------------------------------------------------------ -------------------
int psum = 0;
void setup() // SET UP SOFTWARE
{
// create the Processing environment
size(200,200);
framerate(30);
smooth();
background(255);
// load an image from the user variable "imagename"
BImage startimage;
startimage = loadImage(imagename);
image(startimage, 0, 0);
// convert loaded image to greyscale and spit it upon the screen
color c1 = get(0,0);
color c2 = get(0,0);
float bright = brightness(c1);
for (int x = 0; x < width; x++){
for (int y = 0; y < height; y++){
colorMode(HSB);
c1 = get(x,y);
bright = brightness(c1);
colorMode(RGB);
c2 = color(bright, bright, bright);
set (x,y,c2);
}
}
// create density array - white = 0 and black = 255.
int[][] density = new int[width][height];
for (int x = 0; x < width; x++){
for (int y = 0; y < height; y++){
c1 = get(x,y) & 0xff;
c1 = 255-c1;
density[x][y] = c1;
}
}
// determine total particles to create;
int particlesum = 0;
for (int x = 0; x < width; x++){
for (int y = 0; y < height; y++){
particlesum += density[x][y];
}
}
psum = particlesum;
// create the particle field
background(255);
particle p[] = new particle[particlesum];
int z = 0;
for (int x = 0; x < width; x++){
for (int y = 0; y < height; y++){
if(density[x][y] != 0){
int thisdensity = density[x][y];
for(int particlebirth = 0; particlebirth < thisdensity; particlebirth++){
p[particlebirth] = new particle(x,y,z);
p[particlebirth].update();
}
}
}
}
}
// ------------------------------------------------------------------------ -------------------
void loop() // MAIN SOFTWARE LOOP
{
for (int i = 0; i < psum; i++){
p[i].x += random(-3, 3);
p[i].y += random(-3, 3);
p[i].z += random(-3, 3);
p[i].update();
}
}
// ------------------------------------------------------------------------ -------------------
class particle {
int xloc, yloc, zloc;
particle(int x, int y, int z) {
xloc = x;
yloc = y;
zloc = z;
}
void update() {
push();
noStroke();
fill(0,1);
translate (xloc, yloc, zloc);
box (1,1,1);
pop();
}
}
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kevinP
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Re: Global values
« Reply #2 on: Jan 26th, 2004, 9:56pm » |
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Hi Charles,
Maybe I have part of the answer...
To make a variable initialized in setup() accessible to loop() you can declare it beforehand and then initialize it in setup().
Code:
Star[] myStars;
setup()
{
//..
myStars = new Star[1000];
}
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But I have my own question to go with this... what if one doesn't know how big an array one needs until the time of "user interaction"? Does one then use "java.util.ArrayList"?
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| « Last Edit: Jan 26th, 2004, 9:58pm by kevinP » |
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Kevin Pfeiffer
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kevinP
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Re: Global values
« Reply #3 on: Jan 26th, 2004, 10:46pm » |
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Here's one other thing I see (possibly)...
You wrote:
Code:
void loop() // MAIN SOFTWARE LOOP
{
for (int i = 0; i < psum; i++){
p[i].x += random(-3, 3);
p[i].y += random(-3, 3);
p[i].z += random(-3, 3);
p[i].update();
}
}
// ----------------------------------------------------------------
class particle {
int xloc, yloc, zloc;
particle(int x, int y, int z) {
xloc = x;
yloc = y;
zloc = z;
}
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Shouldn't that be:
p[i].xloc += random(-3, 3);
// etc.
(Not to mention "class Particle"?)
-K
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| « Last Edit: Jan 26th, 2004, 10:46pm by kevinP » |
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Kevin Pfeiffer
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Charles Hinshaw
Guest
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Re: Global values
« Reply #4 on: Jan 26th, 2004, 10:48pm » |
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Thanks, Kevin... It seemed to get that aspect working.
Ok, in a related issue (?) --
here is my refined code:
Code:
// User Control Variables
String imagename = "digidust.jpg"; // Initial Image File in DATA Directory
//Global Variables
particle p[];
int psum = 0;
// ------------------------------------------------------------------------ -------------------
void setup() // SET UP SOFTWARE
{
// create the Processing environment
size(200,200);
framerate(30);
smooth();
background(255);
// load an image from the user variable "imagename"
BImage startimage;
startimage = loadImage(imagename);
image(startimage, 0, 0);
// convert loaded image to greyscale and spit it upon the screen
color c1 = get(0,0);
color c2 = get(0,0);
float bright = brightness(c1);
for (int x = 0; x < width; x++){
for (int y = 0; y < height; y++){
colorMode(HSB);
c1 = get(x,y);
bright = brightness(c1);
colorMode(RGB);
c2 = color(bright, bright, bright);
set (x,y,c2);
}
}
// create density array - white = 0 and black = 255.
int[][] density = new int[width][height];
for (int x = 0; x < width; x++){
for (int y = 0; y < height; y++){
int colors = get(x,y) & 0xff;
colors = 100-int(colors/2.55);
//c1 = 255-c1;
density[x][y] = colors;
}
}
// determine total particles to create;
int particlesum = 0;
for (int x = 0; x < width; x++){
for (int y = 0; y < height; y++){
particlesum += density[x][y];
}
}
psum = particlesum;
// create the particle field
background(255);
particle p[] = new particle[particlesum];
int z = 0;
for (int x = 0; x < width; x++){
for (int y = 0; y < height; y++){
if(density[x][y] != 0){
int thisdensity = density[x][y];
for(int particlebirth = 0; particlebirth < thisdensity; particlebirth++){
p[particlebirth] = new particle(x,y,z);
p[particlebirth].update();
}
}
}
}
}
// ------------------------------------------------------------------------ -------------------
void loop() // MAIN SOFTWARE LOOP
{
int newx = 0;
int newy = 0;
int newz = 0;
for (int i = 0; i < psum; i++){
newx = int(p[i].xloc + random(-3, 3));
newy = int(p[i].yloc + random(-3, 3));
newz = int(p[i].zloc + random(-3, 3));
p[i] = new particle(newx,newy,newz);
p[i].update();
}
}
// ------------------------------------------------------------------------ -------------------
class particle {
int xloc, yloc, zloc;
particle(int x, int y, int z) {
xloc = x;
yloc = y;
zloc = z;
}
void update() {
color c = color(0,0,0,1);
stroke(c);
point(xloc, yloc, zloc);
}
}
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Everything displays fine from the setup(), but I get a null pointer exception when I get to the for loop in the loop().
Does anybody know why?
What I am trying to do is use brownian motion to jiggle my particles in 3 dimensions.
Also -- if anybody has time to scan through and give me a mini-lecture on optimization, it would be very well received.
Thanks,
Charles Hinshaw
direction + repertoire
[r]evolve, US
http://www.everydayrevolution.com
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Charles Hinshaw
Guest
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Re: Global values
« Reply #5 on: Jan 27th, 2004, 12:15am » |
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I have posted the most current related code in a new thread since I no longer believe this to be a global/local issue.
It is in the Syntax section too, if you can help.
thanks,
Charles Hinshaw
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