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|
#!/bin/bash
###
# ASCII fire
# TODO:
# Better gradient for cooling flame.
r=$'\e[31m'
y=$'\e[33m'
br=$'\e[1;31m'
by=$'\e[1;33m'
c=$'\e[0m'
bs=$'\e[1;30m'
#w=$'\e[37m'
flame_gradient=(
# "$w#$c"
"$by@$c"
"$by#$c"
"$y#$c"
"$y@$c"
"$br@$c"
"$br#$c"
"$r#$c"
# "$bs($c"
# "$bs($c"
# "$bs)$c"
# "$bs.$c"
" "
)
# TODO: Use 256 color palette.
declare -ia cells=()
##
# init
tput clear
n_rows=$(tput lines)
n_cols=$(tput cols)
printf 'rows: %d\ncols: %d\n' "$n_rows" "$n_cols"
#for cell in $(seq 0 $(((n_rows * n_cols) - 1)))
for ((cell=0;cell<n_rows*n_cols;++cell))
do cells[cell]=0
done
###
# It is best if the bottom row is row #0.
# Even if the terminal is resized,
# there will always be a row #0.
# Of course this means the rows will be drawn in reverse order.
new_base_row(){
# TODO: If the terminal is resized, re-evaluate the number of columns.
# for cell in $(seq 0 $((n_cols-1)))
declare -i delta=32 # ±16
for ((cell=0;cell<n_cols;++cell))
do cells[cell]=$(((cells[cell]+RANDOM%delta-(delta/2)+256)%256))
done
# TODO: Adjust delta to size of terminal? Not sure how.
}
# end init
##
num_to_cell(){
# Cells have a value between 0 and 255, inclusive.
# Arrays are 0-indexed.
echo -n "${flame_gradient[(255-$1)*${#flame_gradient[@]}/256]}"
# printf makes no apparent difference.
}
##
# Compute the values of the indicated row
# from the values of the row below.
# Indicated row should not be the bottom row.
# TODO: Does a lot of repeatedly computing the same numbers; could be avoided.
burn_row(){
declare -i row_number=$1
declare -i cell
for ((cell=row_number*n_cols;cell<(row_number+1)*n_cols;++cell))
do
cell_l=${cells[$cell-$n_cols-1]}
cell_b=${cells[$cell-$n_cols]}
cell_r=${cells[$cell-$n_cols+1]}
# The flames cool between rows.
cells[cell]=$(((cell_l+cell_b+cell_r)/3-(256/n_rows)))
[[ ${cells[cell]} -lt 0 ]] && cells[cell]=0
done
}
# By burning iteratively, the entire array can be processed at once.
# It is only a matter of direction.
burn(){
declare -i cell cell_l cell_b cell_r
for ((cell=${#cells[@]}-1;cell>=n_cols;--cell))
do
cell_l=${cells[$cell-$n_cols-1]}
cell_b=${cells[$cell-$n_cols]} # cell_l from previous iteration.
cell_r=${cells[$cell-$n_cols+1]} # cell_b from previous iteration.
# The flames cool between rows.
cells[cell]=$(((cell_l+cell_b+cell_r)/3-(256/n_rows)))
[[ ${cells[cell]} -lt 0 ]] && cells[cell]=0
done
}
print_all(){
# Wrong order. This burns downwards.
declare -i cell
for cell in "${cells[@]}"
do
num_to_cell $cell
done
}
print_rows(){
declare -i row
for ((row=n_rows-1;row>=0;--row))
do
# Print rows top to bottom:
tput cup $((n_rows-row)) 0
print_row $row
# Print rows bottom to top:
# tput cup $row 0
# print_row $((n_rows-1-row))
done
# TODO:
# It should be more efficient to print all at once.
}
print_row(){
declare -i row=$1
declare -i cell
for ((cell=row*n_cols;cell<(row+1)*n_cols;++cell))
do
num_to_cell "${cells[cell]}"
done
}
test_fire() {
# Saturate base row.
for ((cell=0;cell<n_cols;++cell))
do cells[cell]=255
done
# Print buffer.
tput cup 0 0
print_rows
# Burn.
for ((counter=0;counter<n_rows;++counter))
do
burn
print_rows
done
}
##
# main
#test_fire
#exit
new_base_row
while :
do
burn
print_rows
new_base_row
tput cup 0 0
# sleep 0.2
# sleep 1
done
|
