Having trouble drawing Sierpinski's Triangle in Processing - processing

Question

I was trying to draw Sierpinski's Triangle in Processing 3, and managed to get it to run the first two layers. However, when it tries to draw the third and any later layers, it only draws more triangles in some of the triangles.
Here's the code
ArrayList<PVector> initPoints;
int level;
void setup() {
size(400, 400);
noFill();
initPoints = new ArrayList<PVector>();
initPoints.add(new PVector(width/2, height/4));
initPoints.add(new PVector(width/4, 3 * height/4));
initPoints.add(new PVector(3 * width/4, 3 * height/4));
}
void draw() {
triangle(initPoints.get(0).x, initPoints.get(0).y, initPoints.get(1).x, initPoints.get(1).y, initPoints.get(2).x, initPoints.get(2).y);
for (int i = 0; i < 3; i++) {
level = 1;
drawTri(i, initPoints, level);
}
}
PVector findMid(PVector a, PVector b) {
int midX = floor((a.x + b.x)/2);
int midY = floor((a.y + b.y)/2);
return new PVector(midX, midY);
}
void drawTri(int vertex, ArrayList<PVector> basePoints, int layer) {
level = layer + 1;
ArrayList<PVector> points = new ArrayList<PVector>();
points.add(basePoints.get(vertex % 3));
points.add(findMid(basePoints.get(vertex % 3), basePoints.get((vertex + 1) % 3)));
points.add(findMid(basePoints.get(vertex % 3), basePoints.get((vertex + 2) % 3)));
triangle(points.get(0).x, points.get(0).y, points.get(1).x, points.get(1).y, points.get(2).x, points.get(2).y);
if (level < 4) {
for (int i = 0; i < 3; i++) {
drawTri(i, points, level);
}
}
}
Any tips? I think it's something to do with how I'm running the for loops but I'm not sure.

Answer 1

Like I said in my comment, please try to debug your program before you post a question. You need to isolate the problem and understand exactly what the code is doing, and you can do that using print statements and the debugger that comes with the Processing editor.
But just looking at your code, I'm suspicious of the fact that you have a sketch-level level variable as well as a level variable that you're passing into the drawTri() function.
Think about the value of that sketch-level level variable as your code executes. Add print statements to see exactly what it's doing.
If I get rid of the sketch-level level variable, I get this, which I'm guessing is closer to what you wanted:

Answer 2

float x = int(random(0,1024));
float y = int(random(0,600));
float ax=512;
float ay=0;
float bx=0;
float by=600;
float cx=1024;
float cy=600;
void setup()
{
size(1024, 600);
background(0);
}
void nextPoint()
{
int r = int(random(1,7));
float X;
float Y;
if(r==1||r==2)
{
X = lerp(x, ax, 0.5) ;
Y= lerp(y, ay, 0.5);
}
else if(r==3||r==4)
{
X = lerp(x, bx, 0.5) ;
Y= lerp(y, by, 0.5);
}
else
{
X = lerp(x, cx, 0.5) ;
Y= lerp(y, cy, 0.5);
}
x=X;
y=Y;
}
void drawPoint()
{
colorMode(HSB,255,255,255);
stroke(map(y, 0, 15000,100,4000),200,255,10);
strokeWeight(1);
point(ax,ay);
point(bx,by);
point(cx,cy);
point(x, y);
}
void draw()
{
for(int i=0;i<100;++i)
{
drawPoint();
nextPoint();
}
}