ii-vision/transcoder/screen.py
2019-03-21 16:10:16 +00:00

234 lines
7.4 KiB
Python

"""Various representations of Apple II video display."""
import numpy as np
# TODO: support DHGR
def bitmap_similarity(a1: np.array, a2: np.array) -> float:
"""Measure bitwise % similarity between two bitmap arrays"""
bits_different = np.sum(np.logical_xor(a1, a2)).item()
return 1. - (bits_different / (np.shape(a1)[0] * np.shape(a1)[1]))
def y_to_base_addr(y: int, page: int = 0) -> int:
"""Maps y coordinate to base address on given screen page"""
a = y // 64
d = y - 64 * a
b = d // 8
c = d - 8 * b
addr = 8192 * (page + 1) + 1024 * c + 128 * b + 40 * a
return addr
Y_TO_BASE_ADDR = [
[y_to_base_addr(y, screen_page) for y in range(192)]
for screen_page in (0, 1)
]
# Array mapping (page, offset) to x (byte) and y coords respectively
PAGE_OFFSET_TO_X = np.zeros((32, 256), dtype=np.uint8)
PAGE_OFFSET_TO_Y = np.zeros((32, 256), dtype=np.uint8)
# Inverse mappings
X_Y_TO_PAGE = np.zeros((192, 40), dtype=np.uint8)
X_Y_TO_OFFSET = np.zeros((192, 40), dtype=np.uint8)
# Mask of which (page, offset) bytes represent screen holes
SCREEN_HOLES = np.full((32, 256), True, dtype=np.bool)
# Dict mapping memory address to (page, y, x_byte) tuple
ADDR_TO_COORDS = {}
def _populate_mappings():
for y in range(192):
for x in range(40):
y_base = Y_TO_BASE_ADDR[0][y]
page = y_base >> 8
offset = y_base - (page << 8) + x
PAGE_OFFSET_TO_Y[page - 32, offset] = y
PAGE_OFFSET_TO_X[page - 32, offset] = x
X_Y_TO_PAGE[y, x] = page - 32
X_Y_TO_OFFSET[y, x] = offset
# This (page, offset) is not a screen hole
SCREEN_HOLES[page - 32, offset] = False
for p in range(2):
a = Y_TO_BASE_ADDR[p][y] + x
ADDR_TO_COORDS[a] = (p, y, x)
_populate_mappings()
class Bytemap:
"""Bitmap array with horizontal pixels packed into bytes."""
def __init__(self, bytemap: np.array = None):
self.bytemap = None # type: np.array
if bytemap is not None:
if bytemap.shape != (192, 40):
raise ValueError("Unexpected shape: %r" % (bytemap.shape,))
self.bytemap = bytemap
else:
self.bytemap = np.zeros((192, 40), dtype=np.uint8)
def to_memory_map(self, screen_page: int) -> "MemoryMap":
# Numpy magic that constructs a new array indexed by (page, offset)
# instead of (y, x).
mmap = self.bytemap[PAGE_OFFSET_TO_Y, PAGE_OFFSET_TO_X]
# Reset whatever values ended up in the screen holes after this mapping
# (which came from default 0 values in PAGE_OFFSET_TO_X)
mmap[SCREEN_HOLES] = 0
return MemoryMap(screen_page, mmap)
class Bitmap:
XMAX = None # type: int
YMAX = None # type: int
def __init__(self, bitmap: np.array = None):
if bitmap is None:
self.bitmap = np.zeros((self.YMAX, self.XMAX), dtype=bool)
else:
if bitmap.shape != (self.YMAX, self.XMAX):
raise ValueError("Unexpected shape: %r" % (bitmap.shape,))
self.bitmap = bitmap
def randomize(self) -> None:
self.bitmap = np.random.randint(
2, size=(self.YMAX, self.XMAX), dtype=bool)
@staticmethod
def _to_bytemap(bitmap) -> Bytemap:
# Insert zero column after every 7
pixels = bitmap.copy()
for i in range(pixels.shape[1] // 7 - 1, -1, -1):
pixels = np.insert(pixels, (i + 1) * 7, False, axis=1)
# packbits is big-endian so we flip the array before and after to
# invert this
return Bytemap(
np.flip(np.packbits(np.flip(pixels, axis=1), axis=1), axis=1))
def to_bytemap(self) -> Bytemap:
return self._to_bytemap(self.bitmap)
def to_memory_map(self, screen_page: int) -> "MemoryMap":
return self.to_bytemap().to_memory_map(screen_page)
@staticmethod
def _from_bytemap(bytemap: Bytemap) -> np.array:
bm = np.unpackbits(bytemap.bytemap, axis=1)
bm = np.delete(bm, np.arange(0, bm.shape[1], 8), axis=1)
# Need to flip each 7-bit sequence
reorder_cols = []
for i in range(bm.shape[1] // 7):
for j in range((i + 1) * 7 - 1, i * 7 - 1, -1):
reorder_cols.append(j)
bm = bm[:, reorder_cols]
return np.array(bm, dtype=np.bool)
@classmethod
def from_bytemap(cls, bytemap: Bytemap) -> "Bitmap":
return cls(cls._from_bytemap(bytemap))
class HGR140Bitmap(Bitmap):
XMAX = 140 # double-wide pixels to not worry about colour effects
YMAX = 192
def to_bytemap(self) -> Bytemap:
# Double each pixel horizontally
return self._to_bytemap(np.repeat(self.bitmap, 2, axis=1))
@classmethod
def from_bytemap(cls, bytemap: Bytemap) -> "HGR140Bitmap":
# Undouble pixels
bitmap = cls._from_bytemap(bytemap)
bitmap = np.array(
np.delete(bitmap, np.arange(0, bitmap.shape[1], 2), axis=1),
dtype=np.bool
)
return HGR140Bitmap(bitmap)
class HGRBitmap(Bitmap):
XMAX = 280
YMAX = 192
class DHGRBitmap(Bitmap):
XMAX = 560
YMAX = 192
class FlatMemoryMap:
"""Linear 8K representation of HGR screen memory."""
def __init__(self, screen_page: int, data: np.array = None):
if screen_page not in [1, 2]:
raise ValueError("Screen page out of bounds: %d" % screen_page)
self.screen_page = screen_page # type: int
self._addr_start = 8192 * self.screen_page
self._addr_end = self._addr_start + 8191
self.data = None # type: np.array
if data is not None:
if data.shape != (8192,):
raise ValueError("Unexpected shape: %r" % (data.shape,))
self.data = data
else:
self.data = np.zeros((8192,), dtype=np.uint8)
def to_memory_map(self):
return MemoryMap(self.screen_page, self.data.reshape((32, 256)))
def write(self, addr: int, val: int) -> None:
"""Updates screen image to set 0xaddr = val (including screen holes)"""
if addr < self._addr_start or addr > self._addr_end:
raise ValueError("Address out of range: 0x%04x" % addr)
self.data[addr - self._addr_start] = val
class MemoryMap:
"""Page/offset-structured representation of HGR screen memory."""
def __init__(self, screen_page: int, page_offset: np.array = None):
if screen_page not in [1, 2]:
raise ValueError("Screen page out of bounds: %d" % screen_page)
self.screen_page = screen_page # type: int
self._page_start = 32 * screen_page
self.page_offset = None # type: np.array
if page_offset is not None:
if page_offset.shape != (32, 256):
raise ValueError("Unexpected shape: %r" % (page_offset.shape,))
self.page_offset = page_offset
else:
self.page_offset = np.zeros((32, 256), dtype=np.uint8)
def to_flat_memory_map(self) -> FlatMemoryMap:
return FlatMemoryMap(self.screen_page, self.page_offset.reshape(8192))
def to_bytemap(self) -> Bytemap:
bytemap = self.page_offset[X_Y_TO_PAGE, X_Y_TO_OFFSET]
return Bytemap(bytemap)
def write(self, page: int, offset: int, val: int) -> None:
"""Updates screen image to set (page, offset)=val (inc. screen holes)"""
self.page_offset[page - self._page_start][offset] = val