Some new apps (wip)

apps/pendlum.py

@@ -0,0 +1,81 @@
+#!/usr/bin/env python3.6
+import numpy as np
+import sys
+import os
+import time
+import colorsys
+
+Nx = int(sys.argv[1])
+Ny = int(sys.argv[2])
+N = 100
+iterations = 2
+try:
+    N = int(sys.argv[3])
+except:
+    pass
+
+def rk4(f, x, dt):
+    k1 = f(x)
+    k2 = f(x+k1*dt/2)
+    k3 = f(x+k2*dt/2)
+    k4 = f(x+k3*dt)
+    return x+dt*(k1+2*k2+2*k3+k4)/6.0
+dt = 0.08 
+m = 1
+l = 1
+g = 1
+
+def sq(x): return x*x
+
+def rhs(x):
+    phi1 = x[0]
+    p1 = x[1]
+    phi2 = x[2]
+    p2 = x[3]
+
+    dphi1 = 6/(m*l*l)*(2*p1-3*np.cos(phi1-phi2)*p2)/(16-9*sq(np.cos(phi1-phi2))) 
+    dphi2 = 6/(m*l*l)*(8*p2-3*np.cos(phi1-phi2)*p1)/(16-9*sq(np.cos(phi1-phi2)))
+
+    dp1 = -0.5*m*l*l*(dphi1*dphi2*np.sin(phi1-phi2)+3*g/l*np.sin(phi1))
+    dp2 = -0.5*m*l*l*(-dphi1*dphi2*np.sin(phi1-phi2)+g/l*np.sin(phi2))
+    return np.array([dphi1, dp1, dphi2, dp2])
+
+s = np.array([np.pi+0.1, 0, np.pi-0.1, 0])
+
+angles = np.linspace(np.pi, np.pi/3, N)+np.random.uniform(-np.pi/6/N, np.pi/6/N, N)
+angles = np.random.uniform(-np.pi/6, np.pi/3, N)+np.pi
+states = [np.array([np.pi, 0, a, 0]) for a in angles]
+
+def clamp(x, min_, max_):
+    return  max(min_, min(max_, x))
+
+buffer = bytearray(b"\x00"*Nx*Ny*3)
+
+def setpixel(x, y, r, g, b):
+    xi = int(Nx*(x+1.2)/2.4)
+    yi = int(Ny*(y+1.2)/2.4)
+    if xi < 0 or xi >= Nx or yi < 0 or yi >= Ny:
+        return
+    idx = xi+Nx*yi
+    buffer[3*idx+0] = r
+    buffer[3*idx+1] = g
+    buffer[3*idx+2] = b
+timestep = 0
+timefac = 0.03
+while True:
+    timestep += 1
+    for s, i in zip(states, range(len(states))):
+        phi1 = s[0]
+        phi2 = s[2]
+        x1 = np.sin(phi1)*l
+        y1 = np.cos(phi1)*l
+        x2 = np.sin(phi2)*l+x1
+        y2 = np.cos(phi2)*l+y1
+        h = 0.2*i/N+0*timestep*timefac/iterations
+        r, g, b = colorsys.hsv_to_rgb(h%1, 1, 1)
+        setpixel(x2, y2, int(r*255), int(g*255), int(b*255))
+        states[i] = rk4(rhs, s, dt/iterations)
+    if timestep > 10*iterations and timestep % iterations == 0:
+        #time.sleep(0.01)
+        os.write(1, buffer)
+

apps/quadratic.py

@@ -0,0 +1,80 @@
+#!/usr/local/bin/python3.6
+
+import numpy as np
+import os
+import sys
+import time
+import colorsys
+
+Nx = int(sys.argv[1])
+Ny = int(sys.argv[2])
+iterations = 10
+
+class Slider:
+    def __init__(self, lo, hi, step, pos=0):
+        self.lo = lo
+        self.hi = hi
+        self.stepSize = step
+        self.pos = 0
+        self.dir = 1
+    
+    def step(self):
+        if self.pos >= self.hi:
+            self.dir = -1
+        elif self.pos <= self.lo:
+            self.dir = 1
+        
+        self.pos += self.dir * self.stepSize
+        return self.pos
+
+Sa = Slider(-10, 10, 0.1/iterations, 0) #1.1
+Sb = Slider(-10, 10, 0.2/iterations, 1) #-2.1
+Sc = Slider(-10, 10, 0.2/iterations, 2) #-0.33
+Sd = Slider(-10, 10, 0.1/iterations, 3) #1.7
+Se = Slider(-10, 10, 0.2/iterations, 4)
+Sf = Slider(-10, 10, 0.01/iterations, 5)
+
+x, y = np.meshgrid(
+    np.linspace(-4, 4, Nx),
+    np.linspace(-4, 4, Ny))
+
+color = 1.0
+
+img = np.zeros( [Ny, Nx, 3] )
+
+cr = 1.0
+cg = 0.5
+cb = 0.25
+
+step = 0
+while True:
+    a = Sa.step()
+    b = Sb.step()
+    c = Sc.step()
+    d = Sd.step()
+    e = Se.step()
+    f = Sf.step()
+
+    curve = (np.abs(a*x**2 + b*x*y + c*y**2 + d*x + e*y + f) <= 1.5)*1
+
+    cr, cg, cb = colorsys.hsv_to_rgb(color, 1, 1)
+
+
+    s = np.shape(curve)
+
+    #img[:,:,0] = curve
+    img[:,:,0] = np.where(curve > 0, curve*cr*255, img[:,:,0])
+    img[:,:,1] = np.where(curve > 0, curve*cg*255, img[:,:,1])
+    img[:,:,2] = np.where(curve > 0, curve*cb*255, img[:,:,2])
+
+    step += 1
+    if step % iterations == 0:
+        out = img.reshape((Nx*Ny*3,)).astype(np.uint8)
+        os.write(1, out.tobytes())
+        time.sleep(0.01)
+
+    color = (color+0.01/iterations ) % 1
+
+    cb = (cb + 0.05) % 1
+
+

config.py

@@ -28,6 +28,8 @@ Apps = [
     {"guiname": "Show Framebuffer", "name": "fbcp", "cmd": ["apps/fbcp", "/dev/fb0"]},
     {"guiname": "Strobo", "name": "strobo", "cmd": "apps/strobo.py"},
     {"guiname": "Beispiel", "name": "example", "cmd": "apps/example.py"},
+    {"guiname": "Quadratisch", "name": "quadratic", "cmd": "apps/quadratic.py"},
+    {"guiname": "Pendel", "name": "pendulum", "cmd": "apps/pendlum.py"},
 
     # juergen/pixelfoo
     {"guiname": "Colored noise", "name": "cnoise", "cmd": "apps/cnoise", "persistent": False},

setup-apps.sh

@@ -7,6 +7,8 @@ chmod +x apps/swifthohenberg.py
 chmod +x apps/strobo.py
 chmod +x apps/example.py
 chmod +x apps/youtubedl.sh
+chmod +x apps/quadratic.py
+chmod +x apps/pendlum.py
 
 
 echo "Building c/c++ apps"