1 files changed, 18 insertions, 0 deletions
diff --git a/bin/rand.rb b/bin/rand.rb
new file mode 100644
index 0000000..f627748
--- /dev/null
+++ b/bin/rand.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+# See values on background.s
+UPPER_MARGIN_Y_COORD = 0x1A
+GROUND_Y_COORD = 0xC8 - 32 # NOTE: As in background.s - twice the size of the enemy.
+
+# The available values for the Y axis for enemies are above ground, below the
+# sky, and avoiding the left-most and right-most platforms.
+available = (UPPER_MARGIN_Y_COORD..GROUND_Y_COORD).to_a - (0x58..0x69).to_a - (0x40..0x50).to_a
+
+# With this produce the array containing a randomized sample from the
+# 'available' values.
+random_byte_array = Array.new(256) { '$%02X' % available.sample }
+
+# And now print it in the assembler format.
+random_byte_array.each_slice(16) do |row|
+  puts ".byte #{row.join(', ')}"
+end