initial broadcom 2d accel code

[cleverca22]

the initial 2d accel code, tested and working on a pi-zero
it should work on the entire vc4 family, bcm2836/2836/2837, just need to update BCM_PERIPH_BASE_VIRT, or find an existing constant that does the same job

will work on it more tomorrow, but am open to comments

features:

• displaying a bitmap at set coords, with 1:1 scale
• up/down scaling
• sprite wide alpha
• moving the REPL framebuffer into a sprite
• properly handling colors
• vsync updating
• aarch64 support
• bcm2711 support

example code.py:

import videocore
import gifio
import time

sprite = videocore.Sprite()
gif = gifio.OnDiskGif("/discord-minecraft.gif")
start = time.monotonic()
next_delay = gif.next_frame()
end = time.monotonic()
overhead = end - start
sprite.image = gif.bitmap

start = time.monotonic()
videocore.HvsChannel1.set_sprite_list([sprite])
end = time.monotonic()
refresh = end-start
print("refresh time:")
print(refresh)

xinc = 3;
yinc = 4;

x = 5
y = 5

while True:
  time.sleep(max(0, next_delay - overhead))
  next_delay = gif.next_frame()
  if (x > 0) and (x < 100):
    x += xinc
  else:
    xinc = xinc * -1
    x += xinc

  if (y > 0) and (y < 100):
    y += yinc
  else:
    yinc = yinc * -1
    y += yinc

  if x < 0:
    x = 0
  if y < 0:
    y = 0
  sprite.x = x
  sprite.y = y
  start = time.monotonic()
  videocore.HvsChannel1.set_sprite_list([sprite])
  end = time.monotonic()
  refresh = end-start
  #print("refresh time:")
  #print(refresh)

[tannewt]

What do you think about adapting Sprite to the TileGrid API and changing the displayio implementation instead? That way existing code would work including the default terminal.