From 87ad58a7f05534218613d229e5d0f5f72a3f323b Mon Sep 17 00:00:00 2001
From: Patrick Kingston <patrick@pkingston.xyz>
Date: Sat, 14 Feb 2026 20:08:44 -0500
Subject: Use spritesheet, make titlescreen

- Moves to using a yychr spritesheet instead
of the included png file
- Sets up and scrolls away a titlescreen!
---
 main.fab | 116 +++++++++++++++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 102 insertions(+), 14 deletions(-)

(limited to 'main.fab')

diff --git a/main.fab b/main.fab
index a47ec27..deb58f8 100644
--- a/main.fab
+++ b/main.fab
@@ -1,21 +1,17 @@
-vars
+vars /allvars
   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
+  U current_rule = 73
 
-fn init_screen()
+fn init_eca_state()
   // 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
@@ -107,7 +103,7 @@ fn upload_curr_gen()
     {PPUDATA}(buf[i+curr_gen])
 
 
-nmi main_nmi()
+nmi eca_nmi()
   // Turn on rendering sprites and bg
   {PPUMASK}(PPUMASK_ON | PPUMASK_NO_CLIP)
 
@@ -115,24 +111,116 @@ nmi main_nmi()
 
   ppu_reset_scroll(0, 0)
 
+// Main mode for running the ECA
+mode eca_main()
+: nmi eca_nmi
+  // Initialize the screen
+  init_eca_state()
+  // Wait 10 frames
+  nmi
+  nmi
+  nmi
+  nmi
+  nmi
+  nmi
+  nmi
+  nmi
+  nmi
+  nmi
+  // Loop forever:
+  while true
+    nmi
+    calc_and_advance_gen()
+
+charmap(".#-=n!@~E$%^S&*(C)_+A{}|12345678qwertyuiop<asd>")
+
+data /titlescreen
+    [] title
+        ("................................"
+         "................................"
+         "................................"
+         "................................"
+         "..........############.........."
+         ".........##############........."
+         ".........##..........##........."
+         ".........##..........##........."
+         ".........##..n!E$S&..##........."
+         ".........##..@~%^*(..##........."
+         ".........##....C)....##........."
+         ".........##...._+....##........."
+         ".........##....A{....##........."
+         ".........##....}|....##........."
+         ".........##..........##........."
+         ".........##..........##........."
+         ".........##############........."
+         "..........############.........."
+         "................................"
+         "................................"
+         "...........###########.........."
+         "..........#..........#.........."
+         "..........#.12345678.#.........."
+         "..........#...<...>..#.........."
+         "..........#..........#.........."
+         "..........###########..........."
+         "................................"
+         "................................"
+         "................................"
+         "................................"
+         "................................")
+
+vars /titlescreen
+  UU wipeline = 0
+
+// nmi for entrypoint for the program
+nmi main_nmi()
+  // Turn on rendering sprites and bg
+  {PPUMASK}(PPUMASK_ON | PPUMASK_NO_CLIP)
 
+  ppu_reset_scroll(0, 0)
+
+  if wipeline
+    UU row_start = $2000
+    row_start += ((wipeline - 1) * 32)
+    ppu_reset_addr(row_start)
+    for U i = 0; i < 32; i += 1 //32 columns
+      //next_cell = 0 //get_next_gen(i)
+      {PPUDATA}(0)
+
+// The main entry point for the program
 mode main()
 : nmi main_nmi
   // Set the palette:
   palette = example_palette
   ppu_upload_palette()
 
-  // Initialize the screen
-  init_screen()
+  ppu_reset_addr($2000)
+
+  // Load the title screen
+  CCC/titlescreen titlep = @title
+  for UU i = 0; i < 960; i += 1
+    {PPUDATA}(titlep{i})
+
+  for UU i = 0; i < 64; i += 1
+    {PPUDATA}(%00000000)
+  
+  // Turn rendering on
+  {PPUMASK}(PPUMASK_BG_ON)
 
   // Turn the NMI on
   {PPUCTRL}(PPUCTRL_NMI_ON)
 
-  // Loop forever:
-  while true
+  // Display title screen for 120 frames
+  for U i = 0; i < 120; i += 1
     nmi
-    calc_and_advance_gen()
+
+  for U i = 1; i <= 30; i += 1 // use this to wipe the screen
+    wipeline = i
+    nmi
+
+  // Go to the main eca mode
+  goto mode eca_main()
+  : preserves /allvars
 
 // Define the tileset (commonly called CHR):
 chrrom
-  file(fmt, "tiles.png")
+  file(fmt, "spritesheet.chr")
-- 
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