{Software} Structure

#003A, #003A Tarbell, and my #003A are all running properly.

Author: tildebyte

Whitney Artport - (Software) Structures/#003/A/Interpretation/Number_003_A_Alkov/Number_003_A_Alkov.pyde

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+'''
+    Modified
+    Structure 3
+
+    A surface filled with one hundred medium to small sized circles.
+    Each circle has a different size and direction, but moves at the
+    same slow rate.
+    Display:
+    A. The instantaneous intersections of the circles
+    B. The aggregate intersections of the circles
+
+    Implemented by Casey Reas <http://groupc.net>
+    8 March 2004
+    Processing v.68 <http://processing.org>
+
+'''
+from circle import Circle
+
+NumCircles = 150
+circles = None
+
+
+def setup():
+    size(1280, 720, P3D)
+    # random x, y based on index value
+    circles = [Circle(random(width), height / NumCircles * i,
+                      (random(1, 6)) * 10, random(-0.7, 0.7),
+                      random(-0.7, 0.7), i) for i in range(NumCircles)]
+    smooth(4)
+    ellipseMode(CENTER)
+    background(173)
+
+
+def draw():
+    background(173)
+    stroke(0)
+    for circle in circles:
+        circle.update(circles)
+        circle.move()
+    noFill()

Whitney Artport - (Software) Structures/#003/A/Interpretation/Number_003_A_Alkov/Number_003_A_mod.pyde

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+class Circle(object):
+    '''A circle object'''
+
+    def __init__(self, centerX, centerY, radius, xspeed, yspeed, index):
+        self.centerX = centerX
+        self.centerY = centerY
+        self.radius = radius
+        self.rSqr = self.radius**2
+        self.index = index
+        self.xspeed = xspeed
+        self.yspeed = yspeed
+
+    def update(self, circles):
+        for circle in circles:
+            if circle.index != self.index:
+                self.intersect(circle)
+
+    def makepoint(self):
+        stroke(0)
+        point(self.centerX, self.centerY)
+
+    def move(self):
+        self.centerX += self.xspeed
+        self.centerY += self.yspeed
+        if self.xspeed > 0 and self.centerX > width + self.radius:
+                self.centerX = -self.radius
+        elif self.centerX < -self.radius:
+                self.centerX = width + self.radius
+        if self.yspeed > 0 and self.centerY > height + self.radius:
+                self.centerY = -self.radius
+        elif self.centerY < -self.radius:
+                self.centerY = height + self.radius
+
+    def intersect(self, other):
+        dx = self.centerX - other.centerX
+        dy = self.centerY - other.centerY
+        dSqr = dx**2 + dy**2
+        diameter = sqrt(dSqr)
+        if diameter > self.radius + other.radius or diameter < abs(self.radius - other.radius):
+            return  # no solution
+        a = (self.rSqr - other.rSqr + dSqr) / (2 * diameter)
+        h = sqrt(self.rSqr - a**2)
+        x2 = self.centerX + a * (other.centerX - self.centerX) / diameter
+        y2 = self.centerY + a * (other.centerY - self.centerY) / diameter
+        paX = x2 + h * (other.centerY - self.centerY) / diameter
+        paY = y2 - h * (other.centerX - self.centerX) / diameter
+        pbX = x2 - h * (other.centerY - self.centerY) / diameter
+        pbY = y2 + h * (other.centerX - self.centerX) / diameter
+        stroke(255 - dist(paX, paY, pbX, pbY) * 2)
+        line(paX, paY, pbX, pbY)