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# The Computer Language Benchmarks Game
# http://shootout.alioth.debian.org/
#
# contributed by Karl von Laudermann
# modified by Jeremy Echols
size = 600 # ARGV[0].to_i
puts "P4\n#{size} #{size}"
ITER = 49 # Iterations - 1 for easy for..in looping
LIMIT_SQUARED = 4.0 # Presquared limit
byte_acc = 0
bit_num = 0
count_size = size - 1 # Precomputed size for easy for..in looping
# For..in loops are faster than .upto, .downto, .times, etc.
for y in 0..count_size
for x in 0..count_size
zr = 0.0
zi = 0.0
cr = (2.0*x/size)-1.5
ci = (2.0*y/size)-1.0
escape = false
# To make use of the for..in code, we use a dummy variable,
# like one would in C
for dummy in 0..ITER
tr = zr*zr - zi*zi + cr
ti = 2*zr*zi + ci
zr, zi = tr, ti
if (zr*zr+zi*zi) > LIMIT_SQUARED
escape = true
break
end
end
byte_acc = (byte_acc << 1) | (escape ? 0b0 : 0b1)
bit_num += 1
# Code is very similar for these cases, but using separate blocks
# ensures we skip the shifting when it's unnecessary, which is most cases.
if (bit_num == 8)
print byte_acc.chr
byte_acc = 0
bit_num = 0
elsif (x == count_size)
byte_acc <<= (8 - bit_num)
print byte_acc.chr
byte_acc = 0
bit_num = 0
end
end
end
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