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vars
U[64] buf // A buffer that can store the current and next row
U curr_gen = 0 // Swap these offsets back and forth per generation
U next_gen = 32
UU drawing_row_offset = 0 // Use this to track which row we're drawing
U current_rule = %00011110
fn init_screen()
// Scroll to attributes
ppu_reset_addr($2000 + 960)
// Set attributes for background
for U i = 0; i < 64; i+= 1
{PPUDATA}(%11111111)
//// Init the buffers to 0
//for i = 0; i < 64; i += 1
// buf[i] = 0
// Init the buffer to zero
buf = U[64]()
// Add an initial cell
buf[16] = 1
fn assemble_code(U left, U middle, U right) U
U out = %00000000
out |= left << 2
out |= middle << 1
out |= right
return out
fn calc_next_cell(U left, U middle, U right) U
U code = assemble_code(left, middle, right)
ct U mask7 = %10000000
ct U mask6 = %01000000
ct U mask5 = %00100000
ct U mask4 = %00010000
ct U mask3 = %00001000
ct U mask2 = %00000100
ct U mask1 = %00000010
ct U mask0 = %00000001
switch code
case %00000111
return (current_rule & mask7) >> 7
case %00000110
return (current_rule & mask6) >> 6
case %00000101
return (current_rule & mask5) >> 5
case %00000100
return (current_rule & mask4) >> 4
case %00000011
return (current_rule & mask3) >> 3
case %00000010
return (current_rule & mask2) >> 2
case %00000001
return (current_rule & mask1) >> 1
case %00000000
return (current_rule & mask0) >> 0
fn calc_and_advance_gen()
// Calculate the next row's values
U left_ind = 0
U right_ind = 0
U left_cell = 0
U mid_cell = 0
U right_cell = 0
U next_cell = 0
for U i = 0; i < 32; i += 1
// Calculate indices for left and right of cell
if i == 0
left_ind = 31
else
left_ind = i - 1
if i == 31
right_ind = 0
else
right_ind = i + 1
// Get left and right of cell
left_cell = buf[curr_gen + left_ind]
mid_cell = buf[curr_gen + i]
right_cell = buf[curr_gen + right_ind]
// Calc next cell
next_cell = calc_next_cell(left_cell, mid_cell, right_cell)
// Set next cell
buf[next_gen + i] = next_cell
// Advance next generation
if curr_gen == 0
curr_gen = 32
next_gen = 0
else
curr_gen = 0
next_gen = 32
// advance drawing row offset, looping back to top
drawing_row_offset += 1
if drawing_row_offset == 30
drawing_row_offset = 0
fn upload_curr_gen()
// "scroll" to the row we're at
UU row_start = $2000
row_start += (drawing_row_offset * 32)
ppu_reset_addr(row_start)
for U i = 0; i < 32; i += 1 //32 columns
//next_cell = 0 //get_next_gen(i)
{PPUDATA}(buf[i+curr_gen])
nmi main_nmi()
// Turn on rendering sprites and bg
{PPUMASK}(PPUMASK_ON | PPUMASK_NO_CLIP)
upload_curr_gen()
ppu_reset_scroll(0, 0)
mode main()
: nmi main_nmi
// Set the palette:
palette = example_palette
ppu_upload_palette()
// Initialize the screen
init_screen()
// Turn the NMI on
{PPUCTRL}(PPUCTRL_NMI_ON)
// Loop forever:
while true
nmi
calc_and_advance_gen()
// Define the tileset (commonly called CHR):
chrrom
file(fmt, "tiles.png")
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