Few questions about a game of life

Programming Questions

err0r_500

Few questions about a game of life

in Programming Questions • 1 year ago

Hi everybody,

First of all, I have to say that I'm pretty new to Processing & Java programming (and not very good in English neither).

I'm trying to improve the Game of life example coming with Processing and I ran into several bugs :

The idea is, instead of calculating if a cell will live or die and draw it, I try to distinguish the two steps and it will cycle on 25 frames :

1st I do the calculation on the frame 0 (call getnextgen() ) then depending on the result, raise or lower the alpha channel of the cell during the 24 first frame (0-23) and during the last frame update its status to a living or dead cell. (I hope it makes sense). Here's my code :

int sx, sy, time, squaresize;
int[][][] world;
void setup()
{
squaresize = 4;
size(640, 480);
frameRate(25);
sx = width/squaresize;
sy = height/squaresize;
time = 0;
world = new int[sx][sy][2];
PFont police;
police = loadFont("Georgia-Italic-25.vlw");
textFont(police,25);
//starting point : a vertical line at the middle of the screen
for (int i = 1; i < sy; i++) {
world[(int)sx/2][(int)i][1] = 1;
}
}
// Birth and death cycle
void getnextgen() {
for (int x = 1; x < sx-1; x++) {
for (int y = 1; y < sy-1; y++) {
int count = neighbors(x, y);
if (count == 3 && world[x][y][0] == 0) //live
{
world[x][y][1] = 1;
}
if ((count < 2 || count > 3) && world[x][y][0] == 1) //die
{
world[x][y][1] = -1;
}
}
}
}
int alpha() {
return (int)(gettime()*10.2);
}
int gettime() {
return time % 25;
}
void draw()
{
background(0);
// time++;//comment to iterate with space bar
if (gettime() == 0) {
getnextgen();
}
for (int x = 1; x < sx-1; x++) {
for (int y = 1; y < sy-1; y++) {
if (gettime() == 24) { //update the cell's status
if (world[x][y][0] == 1 && world[x][y][1] == -1) { //dies
world[x][y][0] = 0;
noStroke();
rect(x*squaresize, y*squaresize, squaresize, squaresize);
fill(0);
}
if (world[x][y][0] == 0 && world[x][y][1] == 1) { //lives
world[x][y][0] = 1;
noStroke();
rect(x*squaresize, y*squaresize, squaresize, squaresize);
fill(0);
}
if (world[x][y][0] == 1 && (world[x][y][1] == 1 || world[x][y][1] == 0)) {//survives
world[x][y][0] = 1;
noStroke();
rect(x*squaresize, y*squaresize, squaresize, squaresize);
fill(255, 255, 255);
}
if (world[x][y][0] == 0 && (world[x][y][1] == -1 || world[x][y][1] == 0)) {//was dead
noStroke();
rect(x*squaresize, y*squaresize, squaresize, squaresize);
fill(0);
world[x][y][0] = 0;
}
else {///////////////////////////////////BUG
noStroke();
rect(x*squaresize, y*squaresize, squaresize, squaresize);
fill(255, 0, 0);
}
}
else { //transition during 24 frames without updating the cell's status
if (world[x][y][1] == 1 && world[x][y][0] == 1) { //stays alive
noStroke();
rect(x*squaresize, y*squaresize, squaresize, squaresize);
fill(255, 255, 255);
}
if ( world[x][y][1] == -1 && world[x][y][0] == 0) { //stays dead
noStroke();
rect(x*squaresize, y*squaresize, squaresize, squaresize);
fill(0);
}
if (world[x][y][1] == 1 && world[x][y][0] == 0) { //live
noStroke();
rect(x*squaresize, y*squaresize, squaresize, squaresize);
fill(255, 255, 255, alpha());
}
if (world[x][y][1] == -1 && world[x][y][0] == 1) { //die
noStroke();
rect(x*squaresize, y*squaresize, squaresize, squaresize);
fill(255, 255, 255, 255 - alpha() );
}
else{
noStroke();
rect(x*squaresize, y*squaresize, squaresize, squaresize);
fill(0);
}
}
}
}
fill(255, 255, 255);
text(gettime(), 20, 35);
}
int neighbors(int x, int y)
{
return world[(x + 1) % sx][y][0] +
world[x][(y + 1) % sy][0] +
world[(x + sx - 1) % sx][y][0] +
world[x][(y + sy - 1) % sy][0] +
world[(x + 1) % sx][(y + 1) % sy][0] +
world[(x + sx - 1) % sx][(y + 1) % sy][0] +
world[(x + sx - 1) % sx][(y + sy - 1) % sy][0] +
world[(x + 1) % sx][(y + sy - 1) % sy][0];
}
void keyPressed() {
int keyIndex = -1;
if (keyIndex == -1) {
time++;
}
}

You can press the space bar to increment the frames.

The bugs :

When I start I got a white cell at something like (2,2) I don't understand why...
I put in red some cells (only at the 24th frame) I don't even understand how they can exist...

Also there are some conditions I had to add to get it working that seems strange to me like : what to do when a cell stays alive or dead... (in fact the whole code seems over complicated to me)

Thanks by advance if someone could push me in the right direction!

Matthieu

Replies(4)

PhiLho

Re: Few questions about a game of life

1 year ago

There are some good ideas, but some errors as well (of course, otherwise you wouldn't have posted here!).
- You need to call noStroke() only once, in setup(), if the whole sketch is in this mode.
- You must call fill() before rect()! fill() doesn't fill the rect, despite the name, it is just a shortcut for "fill color", ie. it defines the fill color for the next drawing orders like rect() or ellipse().
- The rect(x*squaresize, y*squaresize, squaresize, squaresize); call is the same everywhere, you can factor it out of all conditionals.
- Your sentence about the red fill is a bit confusing, but, again, you call fill() after rect(), so it isn't visible.
- The isolated cell is at (1, 1) instead of (2, 2), apparently. Still unsure why we see it.

err0r_500

Re: Few questions about a game of life

1 year ago

Merci beaucoup!

You must call fill() before rect()!

I feel a bit ashamed about this one, you should really have told me to RTFM

Once I fixed that, the code behavior started (obviously) to really make more sense! So I debugged it, the glitches disappeared and it seems to run fine now.

So I have got a new question, I would like to add some color, something like a random color generator but that would affect only the newly created cells but the problem is :

How can I prevent the surviving cells to be redrawn at each generation I tried to remove the fill() statement but it inherits it from the one above it.

Here's the updated code, in red : the surviving cells.

EDIT : Updated the comments to English (and my local file so I don't have to translate it each time...)

int sx, sy, time, squaresize, gen;
float speed;
int[][][] world;
void setup()
{
gen=25;
squaresize = 4;
//size(1280, 640);
size(640, 480);
frameRate(25);
sx = width/squaresize;
sy = height/squaresize;
time = 0;
speed = 2;
//transp=0;
world = new int[sx][sy][2];
noStroke();
smooth();
PFont police;
police = loadFont("Georgia-Italic-25.vlw");
textFont(police, 25);
//starting point : a vertical line at the middle of the screen
for (int x = 1; x < sx; x++) {
for (int y = 1; y < sy; y++) {
world[(int)x][(int)y][0] = 0;
world[(int)x][(int)y][1] = -2;
}
}
for (int i = 0; i < sy; i++) {
world[(int)sx/2][(int)i][1] = 1;
}
}
int alpha() {
return (int)(constrain((gettime() * 255 / gen * speed), 0, 255));
}
int gettime() {
return time % gen;
}
// Birth and death cycle
void getnextgen() {
for (int x = 1; x < sx-1; x++) {
for (int y = 1; y < sy-1; y++) {
int count = neighbors(x, y);
if (world[x][y][0] == 0) {
if (count == 3) { //borns
world[x][y][1] = 1;
}
else {//remains dead
world[x][y][1] = -2;
}
}
if (world[x][y][0] == 1) {
if (count < 2 || count > 3) {//dies
world[x][y][1] = -1;
}
else {//survives
world[x][y][1] = 0;
}
}
}
}
}
void draw()
{
background(0);
time++;//comment to iterate with space bar
if (gettime() == 0) {
getnextgen();
}
for (int x = 1; x < sx-1; x++) {
for (int y = 1; y < sy-1; y++) {
if (gettime() == (gen - 1) ) { //update the cell's status
if (world[x][y][0] == 1 && (world[x][y][1] == 0 || world[x][y][1] == 1)) { //survives
fill(255, 0, 0);
world[x][y][0] = 1;
}
if (world[x][y][0] == 1 && world[x][y][1] == -1) { //dies
fill(0);
world[x][y][0] = 0;
}
if (world[x][y][0] == 0 && world[x][y][1] == -2) { //remains dead
fill(0);
world[x][y][0] = 0;
}
if (world[x][y][0] == 0 && world[x][y][1] == 1) { //borns
fill(255);
world[x][y][0] = 1;
}
}
else { //24 frames transition without updating the cell's status
if (world[x][y][0] == 1 && (world[x][y][1] == 0 || world[x][y][1] == 1)) { //survives
fill(255, 0, 0);
}
if (world[x][y][0] == 1 && world[x][y][1] == -1) { //dies
fill(255, 255, 255, 255 - alpha() );
}
if (world[x][y][0] == 0 && world[x][y][1] == -2) { //remains dead
fill(0);
}
if (world[x][y][0] == 0 && world[x][y][1] == 1) { //borns
fill(255, 255, 255, alpha());
}
}
rect(x*squaresize, y*squaresize, squaresize, squaresize);
}
}
fill(255);
text("frame = " + gettime(), 10, 25);
text("alpha = " + alpha(), 10, 50);
}
int neighbors(int x, int y)
{
return world[(x + 1) % sx][y][0] +
world[x][(y + 1) % sy][0] +
world[(x + sx - 1) % sx][y][0] +
world[x][(y + sy - 1) % sy][0] +
world[(x + 1) % sx][(y + 1) % sy][0] +
world[(x + sx - 1) % sx][(y + 1) % sy][0] +
world[(x + sx - 1) % sx][(y + sy - 1) % sy][0] +
world[(x + 1) % sx][(y + sy - 1) % sy][0];
}
void keyPressed() {
int keyIndex = -1;
if (keyIndex == -1) {
time++;
}
}

PhiLho

Re: Few questions about a game of life

1 year ago

" I feel a bit ashamed about this one"
Actually, you are not the first one to fall in this trap... That's why we quickly spot this kind of error.

" I tried to remove the fill() statement but it inherits it from the one above it."
Yes, fill() persists until a new one, or noFill(), is called. So use either a fill() of the background color, or noFill() if it works.

" //situation de départ, ligne verticale milieu ecran"
When sharing code on the Internet, it is better to use English comments.
Je comprends tes commentaires, mais pas les commentaires en allemand, néerlandais, espagnol (ou à peine), etc. Autant utiliser une langue commune, même si on ne la maîtrise pas...
A common language allows everybody to understand and help.

err0r_500

Re: Few questions about a game of life

1 year ago

>> When sharing code on the Internet, it is better to use English comments.

I updated my comments, sorry, they were in French in my local file and I forgot to translate them as I did in the first post.

>> So use either a fill() of the background color, or noFill() if it works.

These two seem to work as expected, but I would like instead to keep the color they had when they were born instead of making them disappear. I think I would have to store the color value somewhere for each cell and update it only when they born. I'll try to add a dimension to the array and see if it works.

Thanks for your help!

Matthieu

EDIT : here's the code :

int sx, sy, time, squaresize, gen, currentColor, cellRed, cellGreen, cellBlue;
float speed;
int[][][] world;
void setup()
{
gen=25;
squaresize = 4;
//size(1280, 640);
size(640, 480);
frameRate(25);
sx = width/squaresize;
sy = height/squaresize;
time = 0;
speed = 1.5;
world = new int[sx][sy][5]; //0, 1 for current and next generation state// 2, 3, 4 for R, G, B new color
noStroke();
smooth();
PFont police;
police = loadFont("Georgia-Italic-25.vlw");
textFont(police, 25);
//starting point : set everything to dead except a vertical line at the middle of the screen
for (int x = 1; x < sx; x++) {
for (int y = 1; y < sy; y++) {
world[(int)x][(int)y][0] = 0;
world[(int)x][(int)y][1] = -2;
}
}
color startcolor = newColor();
int R = (int)red(startcolor);
int G = (int)green(startcolor);
int B = (int)blue(startcolor);
for (int i = 0; i < sy; i++) {
world[(int)sx/2][(int)i][1] = 1;
world[(int)sx/2][(int)i][2] = R;
world[(int)sx/2][(int)i][3] = G;
world[(int)sx/2][(int)i][4] = B;
}
}
int alpha() {
return (int)(constrain((gettime() * 255 / gen * speed), 0, 255));
}
int gettime() {
return time % gen;
}
color newColor() {
int R = (int)random(255);
int G = (int)random(255);
int B = (int)random(255);
return color(R, G, B);
}
// Birth and death cycle
void getnextgen() {
int cRed, cGreen, cBlue;
currentColor = newColor();
cRed = (int)red(currentColor);
cGreen = (int)green(currentColor);
cBlue = (int)blue(currentColor);
for (int x = 1; x < sx-1; x++) {
for (int y = 1; y < sy-1; y++) {
int count = neighbors(x, y);
if (world[x][y][0] == 0) {
if (count == 3) { //borns
world[x][y][1] = 1;
world[x][y][2] = cRed;
world[x][y][3] = cGreen;
world[x][y][4] = cBlue;
}
else {//remains dead
world[x][y][1] = -2;
}
}
if (world[x][y][0] == 1) {
if (count < 2 || count > 3) {//dies
world[x][y][1] = -1;
}
else {//survives
world[x][y][1] = 0;
}
}
}
}
}
void draw()
{
background(0);
time++;//comment to iterate with space bar
if (gettime() == 0) {
getnextgen();
}
for (int x = 1; x < sx-1; x++) {
for (int y = 1; y < sy-1; y++) {
if (gettime() == (gen - 1) ) { //update the cell's status
if (world[x][y][0] == 1 && (world[x][y][1] == 0 || world[x][y][1] == 1)) { //survives
fill(world[x][y][2], world[x][y][3], world[x][y][4]);
world[x][y][0] = 1;
}
if (world[x][y][0] == 1 && world[x][y][1] == -1) { //dies
fill(0);
world[x][y][0] = 0;
}
if (world[x][y][0] == 0 && world[x][y][1] == -2) { //remains dead
fill(0);
world[x][y][0] = 0;
}
if (world[x][y][0] == 0 && world[x][y][1] == 1) { //borns
fill(world[x][y][2], world[x][y][3], world[x][y][4]);
world[x][y][0] = 1;
}
}
else { //24 frames transition without updating the cell's status
if (world[x][y][0] == 1 && (world[x][y][1] == 0 || world[x][y][1] == 1)) { //survives
fill(world[x][y][2], world[x][y][3], world[x][y][4]);
}
if (world[x][y][0] == 1 && world[x][y][1] == -1) { //dies
fill(world[x][y][2], world[x][y][3], world[x][y][4], (255 - alpha()));
}
if (world[x][y][0] == 0 && world[x][y][1] == -2) { //remains dead
fill(0);
}
if (world[x][y][0] == 0 && world[x][y][1] == 1) { //borns
fill(world[x][y][2], world[x][y][3], world[x][y][4], alpha());
}
}
rect(x*squaresize, y*squaresize, squaresize, squaresize);
}
}
fill(255);
text("frame = " + gettime(), 10, 25);
text("alpha = " + alpha(), 10, 50);
}
int neighbors(int x, int y)
{
return world[(x + 1) % sx][y][0] +
world[x][(y + 1) % sy][0] +
world[(x + sx - 1) % sx][y][0] +
world[x][(y + sy - 1) % sy][0] +
world[(x + 1) % sx][(y + 1) % sy][0] +
world[(x + sx - 1) % sx][(y + 1) % sy][0] +
world[(x + sx - 1) % sx][(y + sy - 1) % sy][0] +
world[(x + 1) % sx][(y + sy - 1) % sy][0];
}
void keyPressed() {
int keyIndex = -1;
if (keyIndex == -1) {
time++;
}
}

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