Make the datastream generation way faster.

Add requirements file

v2/backend/forwarding/requirements.txt

@@ -0,0 +1,2 @@
+redis
+pyserial

v2/backend/processing/PixelControl_TCP/PixelControl_TCP.pyde

@@ -8,11 +8,11 @@ from data_generator import prepare_data
 # Config, will be checked upstream
 height = 5
 width = 8
-framerate = 30
+framerate = 40
 #####################################
 
 gamma = 1.7
-brightness = 4
+brightness = 0.2
 dimension = 0
 
 # TODO: test with real serial
@@ -53,12 +53,12 @@ def setup():
     size(width, height)
     dimension = width * height
     frameRate(framerate)
-    data, gammatable = prepare_data(dimension, gamma, brightness)
+    data = prepare_data(dimension, gamma, brightness)
     loadPixels()
     for i in range(dimension):
         pixels[i] = color(0, 0, 0)
     updatePixels()
-    send_TCP(ledTCP, data, long_line, gammatable)
+    send_TCP(ledTCP, data, long_line)
 
 def draw():
     global current_px
@@ -72,4 +72,4 @@ def draw():
         current_px = 0
     else:
         current_px += 1
-    send_TCP(ledTCP, data, long_line, gammatable)
+    send_TCP(ledTCP, data, long_line)

v2/backend/processing/PixelControl_TCP/data_generator.py

@@ -1,12 +1,53 @@
 import jarray
 import math
+import itertools
 
-def prepare_data(dimension, gamma, brightness):
-    gammatable = [int((math.pow(i / 255.0, gamma) * 255.0 + 0.5) * brightness) for i in range(0, 256)]
+_byte_lookup = {}
+brightness_max = 0.5
+
+# Bit values which represent the zero and one bit pulses.
+_ZERO = bytearray([0b00000000])
+_ONE = bytearray([0b11111111])
+
+def _build_byte_lookup():
+    """Return lookup table to map from every byte value 0-255 and the associated raw SPI data."""
+    lookup = {}
+    for i in range(256):
+        value = bytearray()
+        for j in range(7, -1, -1):
+            if ((i >> j) & 1) == 0:
+                value += _ZERO
+            else:
+                value += _ONE
+        lookup[i] = value
+    return lookup
+
+def color_to_rgb(c):
+    """Convert a 24 bit color to RGB triplets."""
+    return ((c >> 16) & 0xFF, (c >> 8) & 0xFF, c & 0xFF)
+
+def _encode_color_grb(c):
+    """Encode an RGB tuple into NeoPixel GRB 24 byte SPI bit stream."""
+    return _byte_lookup[int(c[1] * brightness)] + _byte_lookup[int(c[0] * brightness)] + _byte_lookup[int(c[2] * brightness)]
+
+def _encode_pixel(c):
+    """Encode an RGB tuple into NeoPixel GRB 24 byte SPI bit stream."""
+    rgb = color_to_rgb(c)
+    encoded = _encode_color_grb(rgb)
+    return encoded
+
+def prepare_data(dimension, gamma, b):
+    global brightness
+    global _byte_lookup
+    if b > brightness_max:
+        brightness = brightness_max
+    else:
+        brightness = b
+    _byte_lookup = _build_byte_lookup()
     data = jarray.zeros(dimension * 24, "b")
-    return data, gammatable
+    return data
 
-def image2data(data, long_line, gammatable):
+def image2data(data, long_line):
     offset = 0
     pixel_nb = 0
     for x in range(0, height):
@@ -14,30 +55,14 @@ def image2data(data, long_line, gammatable):
         if long_line and pixel_nb/width%2 == 1:
             pixel_line = reversed(pixel_line)
         for px in pixel_line:
-            pixel = [colorWiring(px, gammatable) for i in range(0, 8)]
-            imgmask = 0x800000
-            while imgmask != 0:
-                b = 0
-                for i in range(0, 8):
-                    if ((pixel[i] & imgmask) != 0):
-                        b |= (1 << i)
+            py_bytes = _encode_pixel(px)
+            for b in py_bytes:
                 if b > 127:
                     # Convert to signed bytes (expected by jarray)
-                    b -= 2**8
+                    b -= 256
                     data[offset] = b
                 else:
                     data[offset] = b
                 offset += 1
-                imgmask >>= 1
             pixel_nb +=1
     return data
-
-def colorWiring(c, gammatable):
-    red = (c & 0xFF0000) >> 16
-    green = (c & 0x00FF00) >> 8
-    blue = (c & 0x0000FF)
-    red = gammatable[red] >> 8
-    green = gammatable[green] >> 8
-    blue = gammatable[blue] >> 8
-    return (green << 16) | (red << 8) | (blue)
-

v2/backend/processing/PixelControl_TCP/network.py

@@ -25,6 +25,7 @@ def send_config(socket, height, width, framerate):
     socket.write(struct.pack('<i', width))
     socket.write(struct.pack('<i', framerate))
 
-def send_TCP(socket, data, long_line, gammatable):
-    image2data(data, long_line, gammatable)
+def send_TCP(socket, data, long_line):
+    image2data(data, long_line)
+    # print data
     socket.write(data)