Using float()/int() in processing.js

rootle

Using float()/int() in processing.js

in Processing with Other Languages • 3 years ago

I'm experimenting with processing.js, hoping to adapt a sketch I am working on, but when I try exporting it I get a (very nicely explained) error message informing me that I cannot use the functions 'float variable = float(number)'. what other means are there to convert values of different types? - my code below shows that mainly I am needing to convert strings to floats so I can read latitude & longitude values from a text file and use them as floats.

Thanks! R.

float leedsXPos = -1.549072;
float leedsYPos = 53.787672;
float leedsXPosMapped;
float leedsYPosMapped;
float UKLeftEdge = -10.458984;
float UKRightEdge = 1.761932;
float UKTopEdge = 58.671226;
float UKBottomEdge = 49.965356;
float movingXPos;
float movingYPos;
PImage mapImage;
String mapImageUrl = "http://www.samhumphrey.co.uk/studentscattermap/map.png";
String[] databaseRowsArray;
PFont font;
ArrayList studentsArrayList = new ArrayList();
String[] studentNamesArray;
void setup(){
size(283, 341);
mapImage = loadImage(mapImageUrl);
font = createFont("Helvetica", 10);
textFont(font);
frameRate(10);
smooth();
mapImage = loadImage("map.png");
movingXPos = 0;
movingYPos = 0;
leedsXPosMapped = map(leedsXPos, UKLeftEdge, UKRightEdge, 0, width);
leedsYPosMapped = map(leedsYPos, UKTopEdge, UKBottomEdge, 0, height);
//load all students in from list (& count how many objects to ceate).
studentNamesArray = loadStrings("namesList.txt");
int numberOfStudents = studentNamesArray.length;
println("There are "+numberOfStudents+" student records:");
println(studentNamesArray);
println("");
for(int i=0; i<numberOfStudents; i++){
File f = new File(dataPath(studentNamesArray[i]+".txt"));
if (f.exists()) {
println("Loading entries.."+(i+1));
databaseRowsArray = loadStrings(f);//load text file.
println(databaseRowsArray);
studentsArrayList.add(new StudentObject(databaseRowsArray, width/2, height/2));//creates a student object from their entries. // SET HOME X&Y TO THEIR HOMETIWN...?
}
}
println("Loaded all student entries");
println("END OF SETUP.");
}//end of setup.
void draw(){
background(0);
image(mapImage, 0, 0);
for(int i = 0; i < studentsArrayList.size(); i++){//LOOP THROUGH STUDENT OBJECTS..
StudentObject currentObject = (StudentObject) studentsArrayList.get(i);
currentObject.updateXYPos();//draws circles.
}
println("mouseX translated = "+map(mouseX, 0, width, UKLeftEdge, UKRightEdge)+", mouseY translated = "+map(mouseY, 0, height, UKTopEdge, UKBottomEdge));
//println("Y = "+map(mouseY, 0, height, UKTopEdge, UKBottomEdge));
}//end of draw.
class StudentObject{//define class.
//attributes.
String[] databaseEntries;
float[] locationXPos;
float[] locationYPos;
float[] temporaryX;
float[] temporaryY;
//constructor.
public StudentObject(String[] tempDataBaseEntries, float tempLocationXPos, float tempLocationYPos){
databaseEntries = tempDataBaseEntries;
temporaryX = new float[databaseEntries.length];//x array is set to same length as there ae rows in data file.
temporaryY = new float[databaseEntries.length];//y array is set to same length as there ae rows in data file.
locationXPos = new float[databaseEntries.length];
locationYPos = new float[databaseEntries.length];
for(int i=0; i<databaseEntries.length; i++){
temporaryX[i] = map(leedsXPos, UKLeftEdge, UKRightEdge, 0, width);
temporaryY[i] = map(leedsYPos, UKTopEdge, UKBottomEdge, 0, height);
}
}//end of constructor.
void updateXYPos(){
String allEntryDetails;
movingXPos = map(leedsXPos, UKLeftEdge, UKRightEdge, 0, width);
movingYPos = map(leedsYPos, UKTopEdge, UKBottomEdge, 0, height);
for(int i = 1; i < databaseEntries.length; i++){//first row is just category headings.
allEntryDetails = databaseEntries[i];//load row.
//STRING FORMAT - name graduationYear homeTown homeLatitude homeLongitude currentLocation currentLat currentLong status date
int detailsSpacer1 = allEntryDetails.indexOf(" ");//space between name & gradYear.
int detailsSpacer2 = allEntryDetails.indexOf(" ", detailsSpacer1+1);//space between gradYear & homeTown.
int detailsSpacer3 = allEntryDetails.indexOf(" ", detailsSpacer2+1);//space between homeTown & homeX.
int detailsSpacer4 = allEntryDetails.indexOf(" ", detailsSpacer3+1);//space between homeX & homeY.
int detailsSpacer5 = allEntryDetails.indexOf(" ", detailsSpacer4+1);//space between homeY & currentLocation.
int detailsSpacer6 = allEntryDetails.indexOf(" ", detailsSpacer5+1);//space between currentLocation & currentLat.
int detailsSpacer7 = allEntryDetails.indexOf(" ", detailsSpacer6+1);//space between currentLat & currentLong.
int detailsSpacer8 = allEntryDetails.indexOf(" ", detailsSpacer7+1);//space between currentLong & status.
int detailsSpacer9 = allEntryDetails.indexOf(" ", detailsSpacer8+1);//space between status & date.
String currentLocationString = allEntryDetails.substring(detailsSpacer5+1, detailsSpacer6);//location string.
String locationXPosString = allEntryDetails.substring(detailsSpacer7+1, detailsSpacer8);//location xPos string.
String locationYPosString = allEntryDetails.substring(detailsSpacer6+1, detailsSpacer7);//location yPos string.
locationXPos[i] = float(locationXPosString);
locationYPos[i] = float(locationYPosString);
locationXPos[i] = map(locationXPos[i], UKLeftEdge, UKRightEdge, 0, width);
locationYPos[i] = map(locationYPos[i], UKTopEdge, UKBottomEdge, 0, height);
String homeTownXPosString = allEntryDetails.substring(detailsSpacer4+1, detailsSpacer5);//homeTown xPos string.
String homeTownYPosString = allEntryDetails.substring(detailsSpacer3+1, detailsSpacer4);//homeTown yPos string.
float homeTownX = float(homeTownXPosString);
float homeTownY = float(homeTownYPosString);
float homeTownXMapped = map(homeTownX, UKLeftEdge, UKRightEdge, 0, width);
float homeTownYMapped = map(homeTownY, UKTopEdge, UKBottomEdge, 0, height);
stroke(0, 0, 150);
fill(0, 150, 0, 100);
ellipse(leedsXPosMapped, leedsYPosMapped, 20, 20);//ellipse at leeds.
fill(0, 0, 200, 100);
ellipse(homeTownXMapped, homeTownYMapped, 20, 20);//ellipse at hometown.
line(homeTownXMapped, homeTownYMapped, leedsXPosMapped, leedsYPosMapped);//line from homeTown to Leeds.
line(leedsXPosMapped, leedsYPosMapped, temporaryX[0], temporaryY[0]);//line from Leeds to first location entry.
for(int n=0; n<databaseEntries.length-1; n++){//loop through the students entries..
fill(250-(n*50), 0, 0, 100);
stroke(150, 0, 0);
ellipse(temporaryX[n], temporaryY[n], 10, 10);//moving spots from leeds to each location in rows.
if(n<databaseEntries.length-2){
line(temporaryX[n], temporaryY[n], temporaryX[n+1], temporaryY[n+1]);
}
noFill();
println("temporaryY = "+temporaryY[n]);
// if(map(leedsXPos, UKLeftEdge, UKRightEdge, 0, width) > temporaryX[n]){
// bezier(map(leedsXPos, UKLeftEdge, UKRightEdge, 0, width), map(leedsYPos, UKTopEdge, UKBottomEdge, 0, height), map(leedsXPos, UKLeftEdge, UKRightEdge, 0, width)+20, map(leedsYPos, UKTopEdge, UKBottomEdge, 0, height)+20, map(leedsXPos, UKLeftEdge, UKRightEdge, 0, width)-20, map(leedsYPos, UKTopEdge, UKBottomEdge, 0, height)-20, temporaryX[n], temporaryY[n]);
// }else{
// bezier(map(leedsXPos, UKLeftEdge, UKRightEdge, 0, width), map(leedsYPos, UKTopEdge, UKBottomEdge, 0, height), map(leedsXPos, UKLeftEdge, UKRightEdge, 0, width)-20, map(leedsYPos, UKTopEdge, UKBottomEdge, 0, height)+20, map(leedsXPos, UKLeftEdge, UKRightEdge, 0, width)+20, map(leedsYPos, UKTopEdge, UKBottomEdge, 0, height)-20, temporaryX[n], temporaryY[n]);
// }
//line(leedsXPosMapped, leedsYPosMapped, temporaryX[n], temporaryY[n]);
}
}//end of loop through database rows.
change();
}//end of update xp pos.
void change(){//moves initial spot XY (leeds) to location spots.
for(int i = 1; i < databaseEntries.length; i++){
float movingPointX = temporaryX[i-1];
float locationPointX = locationXPos[i];
if(temporaryX[i-1] < floor(locationXPos[i])){
temporaryX[i-1]++;
}else{
temporaryX[i-1]--;
}
if(temporaryY[i-1] < floor(locationYPos[i])){
temporaryY[i-1]++;
}else{
temporaryY[i-1]--;
}
}//end loop.
//println("change = "+map(movingXPos, UKLeftEdge, UKRightEdge, 0, width)+" "+map(movingYPos, UKTopEdge, UKBottomEdge, 0, height));
}//end change.
}//end of class.

Replies(2)

fjenett

Re: Using float()/int() in processing.js

3 years ago

Well, currently there is no way to have this code be cross implementation valid. For processing.js / JavaScript you could use parseFloat() instead of float() which will export without an error.

Edit: just checked and it turns out parseFloat is available in both Processing and Processing.js. So, just replace float() with parseFloat().

therealpo..

Re: Using float()/int() in processing.js

2 years ago

beware that due to the javascript nature of processing.js, declaring your variables as int or float is not enough to ensure they really come out as either ints or floats:

int myvar = 4;
int myothervar = 3;
int result = myvar / myothervar;

In processing, "result" will be a real integer. In processing.js, "result" will actually contain 1.3333333333333333333333333333333 and will stay that value until you (int) cast it explicitly:

int myvar = 4;
int myothervar = 3;
int result = (int)(myvar / myothervar);

See http://processingjs.org/reference/articles/p5QuickStart for all the differences that you'll run into as a Processing developer when you start using processing.js

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