How to save position of point in previous frame

suhit

How to save position of point in previous frame

in Contributed Library Questions • 1 year ago

I am doing the project where I am using the Hands example using SimpleOpenNI example to draw point in realtime on screen. I want to get the position of hand (point) in previous frame so that i can find the difference ho far the hand moved based on that the image will move. Here is my code. Please help

import fullscreen.*;
import japplemenubar.*;
import processing.opengl.*;
import SimpleOpenNI.*;
SimpleOpenNI context;
FullScreen fs;
XnVSessionManager sessionManager;
PushDetectorLab pushDetectorLab;
SwipeDetectorLab swipeDetectorLab;
XnVFlowRouter flowRouter;
PointDrawer pointDrawer;
PVector s = new PVector();
PVector screenPos = new PVector();
PVector v = new PVector();
boolean activeLeft = false;
boolean activeRight = false;
int counter = 0;
PFont fontA32;
PImage shapeOfUser;
boolean foundSkeleton = false;
double offsetX ;
int timeDelay = 10000; //milliseconds in one minute
int time = 0;
boolean blinkText = false;
boolean bWaitText = true;
boolean on;
int blinkSpeed = 12;
final float MAX_ANGLE = radians(70);
final float interval = 500;
final int offsetZ = 500;
final int bgColor = color(255, 255, 255);
Photo[] p = new Photo[8];
PImage logo, newLogo, sky;
PImage waveTextImage;
PImage logo0, logo1, logo2, logo3, logo4, logo5, logo6, logo7;
int val = 255, val1= 255, val2 = 0;
void setup() {
size(1024, 768, OPENGL);
context = new SimpleOpenNI(this, SimpleOpenNI.RUN_MODE_MULTI_THREADED);
String ONI_FILE = "";
if (context.openFileRecording(ONI_FILE)) println("Playing 3d data from "+ONI_FILE);
context.setMirror(true);
if (context.enableDepth() == false)
{
println("Can't open the depthMap, maybe the camera is not connected!");
exit();
return;
}
context.enableHands();
context.enableGesture();
sessionManager = context.createSessionManager("Click,Wave", "RaiseHand");
pushDetectorLab = new PushDetectorLab();
swipeDetectorLab = new SwipeDetectorLab();
pointDrawer = new PointDrawer();
flowRouter = new XnVFlowRouter();
flowRouter.SetActive(pointDrawer);
sessionManager.AddListener(swipeDetectorLab);
sessionManager.AddListener(pointDrawer);
sessionManager.AddListener( flowRouter);
for (int i = 0; i < p.length; i++) {
p[i] = new Photo("img"+i+".jpg");
p[i].nX = (i - p.length / 2) * interval;
}
logo = loadImage("dheeraj.png");
newLogo = loadImage("New_dheeraj.png");
waveTextImage = loadImage("wave_hand_icon.jpg");
sky = loadImage("bg.jpg");
fontA32 = createFont("Arial", 32);
textFont(fontA32, 32);
smooth();
}
void draw() {
beginCamera();
camera();
background(0);
context.update();
context.update(sessionManager);
pointDrawer.draw();
endCamera();
camera(0, 0, 1200, 0, 0, 0, 0, 1, 0);
double minX = 9999;
noTint();
for (int i = 0; i < p.length; i++) {
p[i].update();
if (abs((float) p[i].nX) < abs((float) minX)) minX = p[i].nX;
}
// here i want to save value the value of point in previous frame
v.x = screenPos.x // for each frame the value of hand position will be saved
/* if(frameCount % 30 == 0){
v.x = screenPos.x;
} */
if (activeLeft == true) {
offsetX = 6 * (screenPos.x - v.x); // value of current point - value of point in previous frame
}
else if (activeRight == true) {
offsetX = 6 * (screenPos.x + v.x); // value of current point + value of point in previous frame
}
else {
offsetX = - minX * 0.1;
}
for (int i = 0; i < p.length; i++) {
p[i].nX += offsetX;
break;
}
}
// -----------------------------------------------------------------
// SimpleOpenNI events
void onNewUser(int userId)
{
println("onNewUser - userId: " + userId);
println(" start pose detection");
context.startPoseDetection("Psi", userId);
}
void onLostUser(int userId)
{
println("onLostUser - userId: " + userId);
}
void onStartCalibration(int userId)
{
println("onStartCalibration - userId: " + userId);
}
void onEndCalibration(int userId, boolean successfull)
{
println("onEndCalibration - userId: " + userId + ", successfull: " + successfull);
if (successfull)
{
println(" User calibrated !!!");
context.startTrackingSkeleton(userId);
}
else
{
println(" Failed to calibrate user !!!");
println(" Start pose detection ");
context.startPoseDetection("Psi", userId);
}
}
void onStartPose(String pose, int userId)
{
println("onStartPose - userId: " + userId + ", pose: " + pose);
println(" stop pose detection");
context.stopPoseDetection(userId);
context.requestCalibrationSkeleton(userId, true);
}
void onEndPose(String pose, int userId)
{
println("onEndPose - userId: " + userId + ", pose: " + pose);
}
//////////////////////////////////////////////////
///////////////////////////////////////////////////
// session callbacks
void onStartSession(PVector pos)
{
println("onStartSession: " + pos);
context.removeGesture("Wave,Click");
foundSkeleton = true;
}
void onEndSession()
{
println("onEndSession: ");
context.addGesture("Wave, Click");
}
void onFocusSession(String strFocus, PVector pos, float progress)
{
println("onFocusSession: focus=" + strFocus + ",pos=" + pos + ",progress=" + progress);
}
/////////////////
// HANDS
// -----------------------------------------------------------------
// hand events
void onCreateHands(int handId, PVector pos, float time)
{
println("onCreateHands - handId: " + handId + ", pos: " + pos + ", time:" + time);
foundSkeleton = true;
}
void onUpdateHands(int handId, PVector pos, float time)
{
println("onUpdateHandsCb - handId: " + handId + ", pos: " + pos + ", time:" + time);
foundSkeleton = true;
}
void onDestroyHands(int handId, float time)
{
println("onDestroyHandsCb - handId: " + handId + ", time:" + time);
foundSkeleton = false;
}

here is the pointDrawer class.

/////////////////////////////////////////////////////////////////////////////////////////////////////

// PointDrawer keeps track of the handpoints

class PointDrawer extends XnVPushDetector

{

HashMap _pointLists;

int _maxPoints;

color[] _colorList = {

color(255, 0, 0), color(0, 255, 0), color(0, 0, 255), color(255, 255, 0)

};

int pushed = 0;

public PointDrawer()

{

_maxPoints = 30;

_pointLists = new HashMap();

RegisterPush(this);

}

public void OnPointCreate(XnVHandPointContext cxt)

{

// create a new list

addPoint(cxt.getNID(), new PVector(cxt.getPtPosition().getX(), cxt.getPtPosition().getY(), cxt.getPtPosition().getZ()));

println("onPointCreate " + cxt.getFTime() +":"+cxt.getNUserID()+"("+cxt.getNID() +") "+

cxt.getPtPosition().getX() + " " +

cxt.getPtPosition().getY()+" " +

cxt.getPtPosition().getZ());

}

public void OnPointUpdate(XnVHandPointContext cxt)

{

/*

println("onPointUpdate " + cxt.getFTime() +":"+cxt.getNUserID()+"("+cxt.getNID() +") "+

cxt.getPtPosition().getX() + " " +

cxt.getPtPosition().getY()+" " +

cxt.getPtPosition().getZ());

*/

//println("OnPointUpdate " + cxt.getPtPosition());

addPoint(cxt.getNID(), new PVector(cxt.getPtPosition().getX(), cxt.getPtPosition().getY(), cxt.getPtPosition().getZ()));

}

public void OnPointDestroy(long nID)

{

println("OnPointDestroy, handId: " + nID);

// remove list

if (_pointLists.containsKey(nID))

_pointLists.remove(nID);

}

void onPush(float vel, float angle) {

println(">>>>>>>>> PUSH v:" + vel + "a: " + angle);

pushed = 10;

// println("ID = " + GetPrimaryID()+" immduration: " + GetPushImmediateDuration()+" immoffset: "+GetPushImmediateOffset() );

}

public ArrayList getPointList(long handId)

{

ArrayList curList;

if (_pointLists.containsKey(handId))

curList = (ArrayList)_pointLists.get(handId);

else

{

curList = new ArrayList(_maxPoints);

_pointLists.put(handId, curList);

}

return curList;

}

public void addPoint(long handId, PVector handPoint)

{

ArrayList curList = getPointList(handId);

curList.add(0, handPoint);

if (curList.size() > _maxPoints)

curList.remove(curList.size() - 1);

}

public void draw()

{

if (_pointLists.size() <= 0)

return;

pushStyle();

noFill();

PVector vec;

PVector firstVec;

// PVector screenPos = new PVector();

int colorIndex=0;

// draw the hand lists

Iterator<Map.Entry> itrList = _pointLists.entrySet().iterator();

while (itrList.hasNext ())

{

strokeWeight(2);

stroke(_colorList[colorIndex % (_colorList.length - 1)]);

ArrayList curList = (ArrayList)itrList.next().getValue();

// draw line

firstVec = null;

Iterator<PVector> itr = curList.iterator();

beginShape();

while (itr.hasNext ())

{

vec = itr.next();

if (firstVec == null)

firstVec = vec;

// calc the screen pos

context.convertRealWorldToProjective(vec, screenPos);

//vertex(screenPos.x, screenPos.y);

}

endShape();

// draw current pos of the hand

if (firstVec != null)

{

//active = true;

strokeWeight(8);

context.convertRealWorldToProjective(firstVec, screenPos);

point(screenPos.x, screenPos.y);



s = screenPos;



if (pushed > 0) {

// rect(screenPos.x, screenPos.y, 10, 10);

pushed --;

}

}

colorIndex++;

}

popStyle();

}

}

The Photo class which does places the images in the order

class Photo {

// int w = 640;

// int h = 480;

int width = 640;

int height = 480;

double x;

double z;

private double angle;

double nX;

private double rate = 4.0;

PImage img;

PImage shadowImg;

Photo(String fileName) {

img = loadImage(fileName);

if (img == null) {

img = createImage(300, 300, RGB);

for (int i = 0; i < img.pixels.length; i++) {

img.pixels[i] = 0xFFFFFFFF;

}

}



shadowImg = createImage(img.width, img.height, RGB);

float a = 100;

float dA = - (float)0xFF / img.height;

for (int iy = 0; iy < shadowImg.height; iy++) {

for (int ix = 0; ix < shadowImg.width; ix++) {

if ( a < 0 ) a = 0;

int i = iy * shadowImg.width + ix;

int c = img.pixels[(img.height - iy - 1)*img.width + ix];

int fg = c;

int fR = (0x00FF0000 & fg) >>> 16;

int fG = (0x0000FF00 & fg) >>> 8;

int fB = 0x000000FF & fg;

int bR = (0x00FF0000 & bgColor) >>> 16;

int bG = (0x0000FF00 & bgColor) >>> 8;

int bB = 0x000000FF & bgColor;

int rR = (fR * (int)a + bR * (int)(0xFF - a)) >>> 8;

int rG = (fG * (int)a + bG * (int)(0xFF - a)) >>> 8;

int rB = (fB * (int)a + bB * (int)(0xFF - a)) >>> 8;

shadowImg.pixels[i] = 0xFF000000 | (rR << 16) | (rG << 8) | rB;

}

a += dA;

}

}

void update() {

z = 0;

angle = MAX_ANGLE;

if (nX < 0) angle = -angle;

noStroke();

fill(255);

if (abs((float)x) <= interval + 0.1) {

x = nX;

angle = MAX_ANGLE * x / interval;

z = offsetZ * (interval - abs((float)nX))/interval;

}

else {

x = nX;

double offset = interval;

if (nX < 0) offset = -offset;

x -= offset;

x /= rate;

x += offset;

}

pushMatrix();

translate((float)x, 0, (float)z);

rotateY(-(float)angle);

int n = 20;

float dW = (float)this.width / n;

float dTexW = (float)img.width / n;

/* lights();

beginShape(QUAD_STRIP);

texture(img);

for (int i = 0; i <= n; i++) {

// vertex(-this.width / 2.0 + i*dW, -this.height / 2.0, i*dTexW, 0);

// vertex(-this.width / 2.0 + i*dW, this.height / 2.0, i*dTexW, img.height);

vertex(-250 + i*dW, 0, i*dTexW, 0);

vertex(-250 + i*dW, 568, i*dTexW, img.height);

}

endShape();

noLights();

beginShape(QUAD_STRIP);

texture(shadowImg);

for (int i = 0; i <= n; i++) {

//vertex(-this.width / 2.0 + i*dW, this.height / 2.0, i*dTexW, 0);

// vertex(-this.width / 2.0 + i*dW, this.height * 3.0 / 2.0, i*dTexW, shadowImg.height);

vertex(-250 + i*dW, 568, i*dTexW, 0);

vertex(-250 + i*dW, 1168, i*dTexW, shadowImg.height);

}

endShape(); */





lights();

beginShape(QUAD_STRIP);

texture(img);

for(int i = 0; i <= n; i++) {

vertex(-this.width / 2.0 + i*dW, -this.height / 2.0, i*dTexW, 0);

vertex(-this.width / 2.0 + i*dW, this.height / 2.0, i*dTexW, img.height);

}

endShape();



noLights();

beginShape(QUAD_STRIP);

texture(shadowImg);

for(int i = 0; i <= n; i++) {

vertex(-this.width / 2.0 + i*dW, this.height / 2.0, i*dTexW, 0);

vertex(-this.width / 2.0 + i*dW, this.height * 3.0 / 2.0, i*dTexW, shadowImg.height);

}

endShape();

popMatrix();

}

}

Replies(10)

PhiLho

Re: How to save position of point in previous frame

1 year ago

That's lot of code, using lot of libraries (so I moved the topic).
I suggest to try and make simpler sketches concentrating on the programming question itself, instead of drowning it with code we cannot run.

I have scanned it (instead of reading it) and if I understood the question, you want global variable(s) to hold the previous value from one frame to the next. A bit like what pmouseX is to mouseX. After using the value, assign it to the storage variable, and find it back on next frame.

suhit

Re: How to save position of point in previous frame

1 year ago

tht's exactly I want. I want to save the position of point in previous frame which will give distance same like mouseX and PmouseX. In my project i hv PVector screenPos which gives the current potion of point. I want to save that in some variable ( Pvector s for example) so that I can get the difference. please suggest me how to do it.

Chrisir

Re: How to save position of point in previous frame

1 year ago

you could store it in an arrayList

see https://forum.processing.org/topic/array-list-balls#25080000001223025

balls.add(new Ball(mouseX, mouseY, random(ballWidth), int(random(0,3))));

etc.

see
http://processing.org/reference/ArrayList.html

Chrisir

suhit

Re: How to save position of point in previous frame

1 year ago

Thnks for the help but I am not using arrayList and i want to save hand position (point) in previous frame in some variable so that I can find hw far the hand moved ( difference betn current and previous position of point or hand). see code segment in yello to get the idea.

Chrisir

Re: How to save position of point in previous frame

1 year ago

looks good:

// here i want to save value the value of point in previous frame
v.x = screenPos.x // for each frame the value of hand position will be saved

why not have a ; after v.x = screenPos.x

does it work?

Greetings

suhit

Re: How to save position of point in previous frame

1 year ago

it dosen't work, each time it saves the current position of frame. i want to save previous frame position not the current.

i hv ; after after v.x = screenPos.x (neglect that ; error);

Chrisir

Re: How to save position of point in previous frame

1 year ago

no idea

maybe at the end of draw()

thebizzle

Re: How to save position of point in previous frame

5 months ago

Chrisir is correct, put it in draw.

and if like me you are trying to save a previous frames information, don't update the information from within a method (or at least the same method you are going to be using that data in) otherwise the information gets screwy (sometimes right, sometimes wrong) ...

at least it did form me, I just had to move the type = lastFrame; into draw() directly and above the method that I use that information in.

pauline303

Re: How to save position of point in previous frame

5 months ago

it's true lot of code
so I'm maybe naive, but here's a little tiny stuff which I think does demonstrates it. it has to be adapted in your thing…maybe make a simple reproduction of the error (without openni,…).

PVector v;
PVector screenPos;
float previous, current;
void setup()
{
size(550, 550);
screenPos = new PVector(mouseX, mouseY);
v= new PVector();
v.x= screenPos.x;
}

void draw()
{
screenPos = new PVector(mouseX, mouseY);

if (frameCount%2==0) //I have a doubt on this…is it the best way to detect frame and //previous one ?
{

    previous =v.x;
    v.x= screenPos.x;
    current =v.x;
    println("======================PREVIOUS FRAME======================");
    println("previous: "+previous);
    println("======================CURRENT FRAME======================");
    println("current: "+current);
    println("DISTANCE: "+abs(current-previous));
}
}

pauline303

Re: How to save position of point in previous frame

5 months ago

and this should be a way to "store" them, (last frame vale will be updated just if current value changes).

PVector v;
PVector screenPos;
float previous, current;
float distance;
float savePREVIOUS, saveCURRENT;
float _previous, _current;
void setup()
{
size(550, 550);
screenPos = new PVector(mouseX, mouseY);
v= new PVector();
v.x= screenPos.x;
}

void draw()
{
screenPos = new PVector(mouseX, mouseY);

if (frameCount%2==0)
{
    change_state();
    previous =v.x;

    v.x= screenPos.x;
    current =v.x;

    distance = abs(saveCURRENT-savePREVIOUS);
    println("savePREVIOUS: " +savePREVIOUS+ "     saveCURRENT: " + saveCURRENT);
    println("DISTANCE: "+distance);
}
}

void change_state()
{
if ( _current !=current)
{
    savePREVIOUS = _previous;
    saveCURRENT = _current;
    _current = current;
    _previous = previous;
}
}

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