added bitmap tools

tools/Makefile

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+
+%-pf.hex: %-pf.pbm p4_to_pfbytes.py
+	python p4_to_pfbytes.py $< > $@
+
+%-48.hex: %-48.pbm p4_to_48pix.py
+	python p4_to_48pix.py $< > $@
+
+%-pf.pbm: %.jpg
+	convert $< -resize 40x192\! -colorspace Gray -dither FloydSteinberg $@
+
+%-48.pbm: %.jpg
+	convert $< -resize 48x192\! -colorspace Gray -dither FloydSteinberg $@
+

tools/README

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+
+This directory contains tools for bitmap conversion.
+
+Requires ImageMagick (convert) and Python 2.x.
+
+make <filename>.pf.hex
+
+	Converts a .jpg into a 40-pixel wide playfield bitmap.
+	Cut-and-paste output into program.
+	(See Chapter 20, Asynchronous Bitmaps)
+
+make <filename>.48.hex
+
+	Converts a .jpg into a 48-pixel wide sprite bitmap.
+	Cut-and-paste output into program.
+	(See Chapter 22, A Big 48-Pixel Sprite)
+

tools/galois.c

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+
+/* test of 16-bit Galois LFSR */
+
+#include "stdio.h"
+
+int main()
+{
+    int n = 100;
+    unsigned short x = 1;
+    for (int i=0; i<n; i++) {
+        int c = x&1;
+        x >>= 1;
+        if (c) x ^= 0xd400; // 0b1101010000000000
+        printf("%4x\n", x);
+    }
+    for (int i=0; i<n; i++) {
+        int c = x&0x8000;
+        x <<= 1;
+        if (c) x ^= 0xa801;
+        printf("%4x\n", x);
+    }
+    return 0;
+}

tools/p4_to_48pix.py

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+#!/usr/bin/python
+
+import sys, struct
+
+# playfield bytes, one array for each of 6 columns
+output = [[],[],[],[],[],[]]
+
+# reverse byte
+def rev(n):
+    return int('{:08b}'.format(n)[::-1], 2)
+
+# output bits in given range
+def out(i, pix, lb, hb, reverse=0, shift=0):
+    x = (pix >> lb) & ((1<<(hb-lb))-1)
+    if reverse:
+        x = rev(x)
+    if shift:
+        x = x << shift
+    assert(x>=0 and x<=255)
+    output[i].append(x)
+
+# read PBM (binary P4 format) file
+with open(sys.argv[1],'rb') as f:
+    # read PBM header
+    header = f.readline().strip()
+    assert(header == 'P4')
+    dims = f.readline().strip()
+    if dims[0] == '#':
+        dims = f.readline().strip()
+    width,height = map(int, dims.split())
+    assert(width==48)
+    # read bitmap rows
+    for y in range(0,height):
+        row = bytes(f.read(6) + '\0\0') # pad to 8 bytes
+        # convert to 64-bit integer
+        pix = struct.unpack('<q',row)[0]
+        #print '%010lx' % pix
+        # generate playfield bytes
+        out(0, pix, 0, 8, 0)
+        out(1, pix, 8, 16, 0)
+        out(2, pix, 16, 24, 0)
+        out(3, pix, 24, 32, 0)
+        out(4, pix, 32, 40, 0)
+        out(5, pix, 40, 48, 0)
+
+# output bitmap tables
+for c in range(0,6):
+    print "\talign $100"
+    print "Bitmap%d" % c
+    print "\thex 00"
+    s = '\thex '
+    for i in range(0,height):
+        s += '%02x' % output[c][height-i-1]
+        if i % 16 == 15:
+            print s
+            s = '\thex '
+    if len(s)>5:
+        print s

tools/p4_to_pfbytes.py

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+#!/usr/bin/python
+
+import sys, struct
+
+# playfield bytes, one array for each of 6 columns
+output = [[],[],[],[],[],[]]
+
+# reverse byte
+def rev(n):
+    return int('{:08b}'.format(n)[::-1], 2)
+
+# output bits in given range
+def out(i, pix, lb, hb, reverse=0, shift=0):
+    x = (pix >> lb) & ((1<<(hb-lb))-1)
+    if reverse:
+        x = rev(x)
+    if shift:
+        x = x << shift
+    assert(x>=0 and x<=255)
+    output[i].append(x)
+
+# read PBM (binary P4 format) file
+with open(sys.argv[1],'rb') as f:
+    # read PBM header
+    header = f.readline().strip()
+    assert(header == 'P4')
+    dims = f.readline().strip()
+    if dims[0] == '#':
+        dims = f.readline().strip()
+    width,height = map(int, dims.split())
+    assert(width==40)
+    # read bitmap rows
+    for y in range(0,height):
+        row = bytes(f.read(5) + '\0\0\0') # pad to 8 bytes
+        # convert bytes from MSB first to LSB first
+        row2 = ''
+        for i in range(0,8):
+            row2 += chr(rev(ord(row[i])))
+        # convert to 64-bit integer
+        pix = struct.unpack('<q',row2)[0]
+        #print '%010lx' % pix
+        # generate playfield bytes
+        out(0, pix, 0, 4, 0, 4)
+        out(1, pix, 4, 12, 1)
+        out(2, pix, 12, 20, 0)
+        out(3, pix, 20, 24, 0, 4)
+        out(4, pix, 24, 32, 1)
+        out(5, pix, 32, 40, 0)
+
+# output bitmap tables
+for c in range(0,6):
+    print "\talign $100"
+    print "PFBitmap%d" % c
+    print "\thex 00"
+    s = '\thex '
+    for i in range(0,height):
+        s += '%02x' % output[c][height-i-1]
+        if i % 16 == 15:
+            print s
+            s = '\thex '
+    if len(s)>5:
+        print s