How to connect points generated from a for loop

Raykza · October 2017

Hi everyone! I'm working on a function plotter, utilizing controlP5 as an interface, so that I can easily manipulate the values of the functions. The problem is that im generating points to make the function's line; to minimize the lag, I tried to reduce the number of points, but by doing so, the graph looks pretty bad (or, if the number of points is low enough, there is not even a clear line). I need some way that I can connect those points one to the next one, so the function still looks clear.

import controlP5.*;
import java.util.*;

PVector middle;
float numbera = 0;
float numberb = 0;
float numberc = 0;
float numberd = 0;

ControlP5 cp5;
Slider mySlider;
Knob Knob;

void setup()
{
  size(800, 800);
  middle = new PVector(width/2, height/2, 0);

  cp5 = new ControlP5(this);

  cp5.addSlider("numbera")
    .setPosition(0, 0)
    .setSize(width, height/50)
    .setRange(-1000, 1000)
    .setSliderMode(Slider.FLEXIBLE)
    .setValue(0)
    ;

  cp5.addSlider("numberb")
    .setPosition(0, height/50)
    .setSize(width, height/50)
    .setRange(-5, 5)
    .setSliderMode(Slider.FLEXIBLE)
    .setValue(0)
    ;


  cp5.addSlider("numberc")
    .setPosition(0, (height/50)*2)
    .setSize(width, height/50)
    .setRange(-100, 100)
    .setSliderMode(Slider.FLEXIBLE)
    .setValue(0)
    ;


  cp5.addSlider("numberd")
    .setPosition(0, (height/50)*3)
    .setSize(width, height/50)
    .setRange(-height, height)
    .setSliderMode(Slider.FLEXIBLE)
    .setValue(0)
    ;

  Knob = cp5.addKnob("grade")
    .setRange(1, 4)
    .setValue(0)
    .setPosition(10, height/2+height/3)
    .setRadius(50)
    .setNumberOfTickMarks(3)
    .snapToTickMarks(true)
    .setDragDirection(Knob.VERTICAL)
    ;
}


void draw()
{
  frameRate(60);
  colorMode(RGB);
  int grade = int(cp5.get(Knob.class, "grade").getValue());
  float numbera = -(1/(cp5.get(Slider.class, "numbera").getValue()));
  float numberb = (cp5.get(Slider.class, "numberb").getValue());
  float numberc = -(cp5.get(Slider.class, "numberc").getValue());
  float numberd = -(cp5.get(Slider.class, "numberd").getValue());
  background(200);
  String desc = "f(x) = "+(int(-1/numbera))+"X³ +("+(int(numberb))+")X² +("+(int(-numberc))+")X+("+(int(-numberd))+")";
  textSize(20);
  text(desc, 0, 85);
  ellipse(middle.x, middle.y, 5, 5);
  fill(0);
  line(middle.x, height, middle.x, 0);
  line(width, middle.y, 0, middle.y);
  stroke(0);
  switch(grade)
  {
    case(1):
    {
      linearPoints(numberc, numberd, -height, height);
      break;
    }
    case(2):
    {
      quadraticPoints(numberb, numberc, numberd, -height, height);
      break;
    }
    case(3):
    {
      cubicPoints(numbera, numberb, numberc, numberd, -height, height);
      break;
    }
  }

  stroke(0);
}

void linearPoints(float a, float b, float xmin, float xmax)
{
  float y;
  for (float x = xmin; x < xmax; x = x + 0.09)
  {
    y = a*x + b;
    point(middle.x+x, middle.y+y);
    stroke(255, 0, 0);
  }
}

void quadraticPoints(float a, float b, float c, float xmin, float xmax)
{
  float y;
  for (float x = xmin; x < xmax; x = x + 0.8)
  {
    y = a*x*x + b*x + c;
    point(middle.x+x, middle.y+y);
    stroke(255, 0, 0);
    textSize(20);
  }
}

void cubicPoints(float a, float b, float c, float d, float xmin, float xmax)
{
  float y;
  for (float x = xmin; x < xmax; x = x+0.02)
  {
    y = a*x*x*x + b*x*x + c*x + d;
    point(middle.x+x, middle.y+y);
    stroke(255, 0, 0);
  }
}

jeremydouglass · October 2017

These past discussions might be relevant:

Raykza · October 2017

Thanks!!

Howdy, Stranger!

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How to connect points generated from a for loop

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