Processing3DGraph

import processing.core.PApplet;

import java.io.File;
import java.util.Objects;
import java.util.function.Function;

@FunctionalInterface
interface TriFunction<A, B, C, R> {

    R apply(A a, B b, C c);

    default <V> TriFunction<A, B, C, V> andThen(
            Function<? super R, ? extends V> after) {
        Objects.requireNonNull(after);
        return (A a, B b, C c) -> after.apply(apply(a, b, c));
    }
}

public class ThreeDGraph extends PApplet {
    //Change the variables below as you like.
    private int delta = 5; //The lower the number, the less pixelated. pixelCount=sizeX*sizeY/delta, so be careful!
    private final float speed = .065f; //How fast it animates.
    private final boolean stroke = false; //Draw a grid?
    private final boolean colored = false; //Use rainbows instead of gray scale (true is hue=f(x,y,time), false is shade=f(x,y,time))
    private final boolean animate = true; //Animate the graph
    private final boolean deltaTime = false; //Makes the program run using delta time instead of frame count
    private final boolean clearWhenDone = false; //Makes the screen clear when the spiral has finished drawing.
    private final int rectsPerFrame = -1; //How many rectangles/"pixels" can be drawn per frame
    private final float numCirclesX = 5; //How many circles to draw on the X axis
    private final float numCirclesY = 5; //How many circles to draw on the Y axis
    private final float rotateVal = random(75); //How much to rotate each pixel
    private final boolean rotate = false; //If the graph should be rotated
    private final boolean saveImages = false; //Whether or not each frame should be saved as an image automatically.
    private final String autoSpiralsDir = "C:/Users/Nicholas/Pictures/autoSpirals/"; //The directory to store auto-saved images
    private final String manualSpiralsDir = "C:/Users/Nicholas/Pictures/manualSpirals/"; //The directory to store manually saved images
    private final TriFunction<Float, Float, Float, Float> shadeFunction = (x, y, time) -> map(((sin(y)+cos(x)+time)+1)*2%2-1, -1, 1, 0, 255); //What 4D function to graph (3D w/time)

    //Don't change the variables below.
    private boolean finished = false;
    private boolean clear = false;
    private float xFactor = 0, yFactor = 0;
    private int lastI = -1;
    private int currentFrame = 0;


    public void setup() {
        delta = delta >= 1 ? delta : 1; //Delta must be at least 1.
        background(0);
        strokeWeight(1);
    }

    public void settings() {
        size(1000, 1000);
    }

    public void keyPressed() {
        if (key == 'a') //Shifts the graph to down
            xFactor -= rotateVal!=0 ? (float)(1D / rotateVal) : 0;
        else if (key == 'q') //Shifts the graph up
            xFactor += rotateVal!=0 ? (float)(1D / rotateVal) : 0;
        else if (key == 'w') //Shifts the graph to the left
            yFactor += rotateVal!=0 ? (float)(1D / rotateVal) : 0;
        else if (key == 's') //Shifts the graph to the right
            yFactor -= rotateVal!=0 ? (float)(1D / rotateVal) : 0;
        else if (key == ' ') //Makes the graph only show what's currently being drawn
            clear = !clear;
        else if (key == 'd') { //Saves an image of the current screen
            int i;
            for (i = 0; new File(manualSpiralsDir + i + ".png").exists(); i++) {
            }
            saveFrame(manualSpiralsDir + i + ".png");
        }

        println(xFactor + "," + yFactor);
        background(0);
    }

    //Initializing vars; don't change these.
    int lastTick = 0;
    private float time = 1;

    public void draw() {
        if (finished) {
            if (saveImages) {
                int spiral = -1;
                while (new File(autoSpiralsDir + (++spiral) + ".png").exists()) {
                }
                saveFrame(autoSpiralsDir + spiral + ".png");
            }
            if (!deltaTime)
                time += speed;
            else
                time += (millis() - lastTick) * speed / 40; //Yay, delta time!
        }
        if (deltaTime)
            lastTick = millis(); //More delta time!
        int rectX, rectY;
        if (clear)
            background(0);
        if (!stroke)
            noStroke();
        float x, y, shade;
        for (int i = lastI + 1; i < width * height / delta; i++) {
            rectX = delta * (i / (width / delta));
            rectY = delta * (i % (width / delta));
            x = map(rectX, 0, width / delta, 0, numCirclesX * PI / delta);
            y = map(rectY, 0, height / delta, 0, numCirclesY * PI / delta);
            shade = shadeFunction.apply(x, y, time);
            if (colored) { //Make the Z axis of the graph hue
                colorMode(HSB);
                fill(shade, 360, 360);
            } else { //Make the Z axis of the graph grayscale shade
                colorMode(RGB);
                fill(shade);
            }
            rect(rectX , rectY, delta, delta);
            if (i != 0 && rectsPerFrame!=-1 && i % rectsPerFrame == 0) {
                finished = false;
                lastI = i;
                break;
            } else if (i == width * height / delta - 1) {
                finished = true;
                lastI = -1;
                if (clearWhenDone)
                    background(0);
            }

            translate(width * xFactor, height * yFactor);
            if (rotate)
                rotate(rotateVal);
        }
    }

    public static void main(String[] args) {
        PApplet.main(new String[] {ThreeDGraph.class.getName()});
    }
}