26a

2020/sketch_2020_08_26a/sketch_2020_08_26a.pyde

@@ -0,0 +1,40 @@
+x = -400
+y = -400
+xv, yv = -1, -1
+
+def setup():
+    size(600, 400)
+    global img 
+    img = loadImage("P1030601.JPG")
+    # img = loadImage("P1030634.JPG")
+    frameRate(30)
+    noSmooth()
+    
+def draw():
+    global x, y, xv, yv
+    background(0)
+    step = 4
+    strokeWeight(3)
+    for i in range(0, width, step):
+        for j in range(0, height, step):
+            if inside_img(i - x, j - y, img):
+                c = img.get(i - x, j - y)
+                stroke(c)
+                point(i,j)
+    # image(img, x, y)
+    x = int(x + xv)
+    y = int(y + yv)
+    if x < -img.width + width: xv = -xv
+    if x > 0: xv = -xv
+    if y < -img.height + height: yv = -yv
+    if y > 0: yv = -yv
+    print(frameRate, x, y)
+    
+def inside_img(x, y, img):
+    return 0 < x < img.width and 0 < y < img.height
+
+def keyPressed():
+    global x, y, xv, xy
+    if key == ' ':
+        xv = random(-3, 3)
+        yv = random(-3, 3)        

2020/sketch_2020_08_26b/sketch_2020_08_26b.pyde

@@ -0,0 +1,65 @@
+pa = [(100, 100), (300, 50), (300, 300)]
+pb = [(150, 150), (250, 100), (250, 250), (100, 250)]
+
+
+def setup():
+    size(400, 400)
+    strokeWeight(5)
+    
+def draw():
+    
+    pc = clip_poly(pa, pb)
+    
+    noFill()
+    stroke(200, 0, 0)
+    draw_poly(pa)
+    stroke(0, 200, 0)
+    draw_poly(pb)
+    if keyPressed:
+        stroke(0, 0, 200)
+        draw_poly(pc)
+
+    
+            
+def draw_poly(poly, closed=True):
+    beginShape()
+    for p in poly:
+        vertex(*p)
+    if closed:
+        endShape(CLOSE)
+    else:
+        endShape()
+    
+
+def clip_poly(subjectPolygon, clipPolygon):
+   def inside(p):
+      return(cp2[0]-cp1[0])*(p[1]-cp1[1]) > (cp2[1]-cp1[1])*(p[0]-cp1[0])
+ 
+   def computeIntersection():
+      dc = [ cp1[0] - cp2[0], cp1[1] - cp2[1] ]
+      dp = [ s[0] - e[0], s[1] - e[1] ]
+      n1 = cp1[0] * cp2[1] - cp1[1] * cp2[0]
+      n2 = s[0] * e[1] - s[1] * e[0] 
+      n3 = 1.0 / (dc[0] * dp[1] - dc[1] * dp[0])
+      return [(n1*dp[0] - n2*dc[0]) * n3, (n1*dp[1] - n2*dc[1]) * n3]
+ 
+   outputList = subjectPolygon
+   cp1 = clipPolygon[-1]
+ 
+   for clipVertex in clipPolygon:
+      cp2 = clipVertex
+      inputList = outputList
+      outputList = []
+      s = inputList[-1]
+ 
+      for subjectVertex in inputList:
+         e = subjectVertex
+         if inside(e):
+            if not inside(s):
+               outputList.append(computeIntersection())
+            outputList.append(e)
+         elif inside(s):
+            outputList.append(computeIntersection())
+         s = e
+      cp1 = cp2
+   return(outputList)

2020/sketch_2020_08_26c/sketch_2020_08_26c.pyde

@@ -0,0 +1,69 @@
+pa = [(100, 100), (300, 50), (300, 300)]
+pb = [(150, 150), (250, 100), (250, 250), (100, 250)]
+
+
+def setup():
+    size(400, 400)
+    strokeWeight(5)
+    
+def draw():
+    
+    pc = clip_poly(pa, pb)
+    
+    noFill()
+    stroke(200, 0, 0)
+    draw_poly(pa)
+    stroke(0, 200, 0)
+    draw_poly(pb)
+    if keyPressed:
+        stroke(0, 0, 200)
+        draw_poly(pc)
+
+    
+            
+def draw_poly(poly, closed=True):
+    beginShape()
+    for p in poly:
+        vertex(*p)
+    if closed:
+        endShape(CLOSE)
+    else:
+        endShape()
+    
+
+def clip_poly(subjectPolygon, clipPolygon):
+
+    def inside(p):
+        return (cp2[0] - cp1[0]) * (p[1] - cp1[1]) > (cp2[1] - cp1[1]) * (p[0] - cp1[0])
+
+    def intersection():
+        dc = [cp1[0] - cp2[0], cp1[1] - cp2[1]],
+        dp = [s[0] - e[0], s[1] - e[1]],
+        n1 = cp1[0] * cp2[1] - cp1[1] * cp2[0],
+        n2 = s[0] * e[1] - s[1] * e[0],
+        n3 = 1.0 / (dc[0] * dp[1] - dc[1] * dp[0])
+        return [(n1 * dp[0] - n2 * dc[0]) * n3, (n1 * dp[1] - n2 * dc[1]) * n3]
+
+    outputList = subjectPolygon
+    cp1 = clipPolygon[-1]
+    for j in clipPolygon:
+        cp2 = clipPolygon[j]
+        inputList = outputList
+        outputList = []
+        s = inputList[-1]  # last on the input list
+        for i in inputList:
+            e = inputList[i]
+            if (inside(e)):
+                if not inside(s):
+                    outputList.append(intersection())
+
+                outputList.append(e)
+
+            elif (inside(s)):
+                outputList.append(intersection())
+
+            s = e
+
+        cp1 = cp2
+
+    return outputList