Cosmic Unicorn: RGB channels example in ulab/numpy.

micropython/examples/cosmic_unicorn/numpy/rgb_channels.py

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+import gc
+import time
+from cosmic import CosmicUnicorn
+from picographics import PicoGraphics, DISPLAY_COSMIC_UNICORN, PEN_RGB888
+from ulab import numpy
+
+"""
+This example demonstrates how to work with full RGB888 colour in ulab/numpy.
+
+Each colour channel is given its own array, and these are combined before
+copying them into the PicoGraphics buffer.
+
+At great cost to performance (about half the speed) this example works in
+floating point 0.0 to 1.0 and converts the result to 8bits per channel.
+"""
+
+# MAXIMUM OVERKILL
+# machine.freq(250_000_000)
+
+cu = CosmicUnicorn()
+cu.set_brightness(0.5)
+graphics = PicoGraphics(DISPLAY_COSMIC_UNICORN, pen_type=PEN_RGB888)
+
+
+def update():
+    # Do something basic with the colour channels
+    # to prove this actually works.
+    red[:] = numpy.roll(red, 1, axis=1)
+    green[:] *= 0.999   # Slowly desaturate green
+    blue[:] *= 1.001    # Slowly saturate blue
+
+
+def draw():
+    # Copy the red, green, blue channels into
+    # their respective places in the RGB_ array
+    rgb[2::4] = red.flatten()
+    rgb[1::4] = green.flatten()
+    rgb[0::4] = blue.flatten()
+
+    # Convert the results to 8bit RGB and copy to the framebuffer
+    memoryview(graphics)[:] = numpy.ndarray(numpy.clip(rgb, 0, 1) * 255, dtype=numpy.uint8).tobytes()
+
+    # Copy the framebuffer to Cosmic
+    cu.update(graphics)
+    # Whew!
+
+
+width, height = graphics.get_bounds()
+
+# Individual channels
+red = numpy.zeros((height, width))
+green = numpy.zeros((height, width))
+blue = numpy.zeros((height, width))
+
+# Reserved for combined channels
+rgb = numpy.zeros((width * height * 4),)
+
+# Stick some gradients in the channels so we have something to look at
+red[::] = numpy.linspace(0, 1, width)
+
+# There has to be a better way!?
+for x in range(width):
+    green[::, x] = numpy.linspace(0, 1, width)
+    blue[::, x] = numpy.linspace(1, 0, width,)
+
+t_count = 0
+t_total = 0
+
+while True:
+    tstart = time.ticks_ms()
+    gc.collect()
+    update()
+    draw()
+    tfinish = time.ticks_ms()
+
+    total = tfinish - tstart
+    t_total += total
+    t_count += 1
+
+    if t_count == 60:
+        per_frame_avg = t_total / t_count
+        print(f"60 frames in {t_total}ms, avg {per_frame_avg:.02f}ms per frame, {1000/per_frame_avg:.02f} FPS")
+        t_count = 0
+        t_total = 0
+
+    # pause for a moment (important or the USB serial device will fail)
+    # try to pace at 60fps or 30fps
+    if total > 1000 / 30:
+        time.sleep(0.0001)
+    elif total > 1000 / 60:
+        t = 1000 / 30 - total
+        time.sleep(t / 1000)
+    else:
+        t = 1000 / 60 - total
+        time.sleep(t / 1000)