From 96f2e943e60a13f4dd3ae4fd266e95d991b7daf2 Mon Sep 17 00:00:00 2001
From: Lukas Krickl <lukas@krickl.dev>
Date: Mon, 9 Feb 2026 07:41:25 +0100
Subject: [PATCH] mapgen: wip map buffer

This buffer is used to generate a tilemap.
Added buffer clear and map seed management.
---
 src/mapgen.s | 39 ++++++++++++++++++++++++++++++++++++---
 src/mem.s    |  4 ++++
 src/update.s |  2 ++
 src/wram.s   | 17 ++++++++++++-----
 4 files changed, 54 insertions(+), 8 deletions(-)

diff --git a/src/mapgen.s b/src/mapgen.s
index 63248a1..609804e 100644
--- a/src/mapgen.s
+++ b/src/mapgen.s
@@ -1,10 +1,43 @@
 	; generates a map
 	; inputs:
-	; map_gen_: map gen settings
-	; writes map to map buffer and map_gen_header
+	; mapgen_: map gen settings
+	; writes map to map buffer and mapgen_header
+	; writes tiles to mapgen_tiles
 map_generate:
+	; clear the map
+	ld d, TT_WALL
+	ld hl, mapgen_tiles
+	ld bc, MAP_TILES
+	call memset
+	
+	; 1) setup seed
+	; store exiting seed in tmp game seed
+	ld a, [srand]
+	ld [mapgen_game_seed], a
+	ld a, [srand+1]
+	ld [mapgen_game_seed+1], a
+
 	; load the seed
+	ld a, [mapgen_seed]
+	ld [srand], a
+	ld a, [mapgen_seed+1]
+	ld [srand+1], a
+
+	; 2) set up map header
+
+
 	
 
-	; restore old seed from rng
+	; cleanup) finally
+	; store current seed
+	ld a, [srand]
+	ld [mapgen_seed], a
+	ld a, [srand+1]
+	ld [mapgen_seed+1], a
+
+	; restore game seed from rng
+	ld [mapgen_game_seed], a
+	ld [srand], a
+	ld [mapgen_game_seed+1], a
+	ld [srand+1], a
 	ret
diff --git a/src/mem.s b/src/mem.s
index c0b898b..21b9d2e 100644
--- a/src/mem.s
+++ b/src/mem.s
@@ -43,15 +43,19 @@ mem_init:
 	ld a, 0xde
 	ld [tiles_canary], a
 	ld [render_canary], a
+	ld [mapgen_canary], a
 	ld a, 0xad
 	ld [tiles_canary+1], a
 	ld [render_canary+1], a
+	ld [mapgen_canary+1], a
 	ld a, 0xbe
 	ld [tiles_canary+2], a
 	ld [render_canary+2], a
+	ld [mapgen_canary+2], a
 	ld a, 0xef
 	ld [tiles_canary+3], a
 	ld [render_canary+3], a
+	ld [mapgen_canary+3], a
 #endif
 
   ret
diff --git a/src/update.s b/src/update.s
index a137865..11210a8 100644
--- a/src/update.s
+++ b/src/update.s
@@ -159,6 +159,8 @@ update_render:
 	ret
 	
 new_game:
+	call map_generate
+
 	call player_init
 	ld de, l1
 	call map_load
diff --git a/src/wram.s b/src/wram.s
index d1b01be..762573b 100644
--- a/src/wram.s
+++ b/src/wram.s
@@ -30,7 +30,7 @@ scrn_select: .adv 1
 game_state: .adv 2 
 
 	; self modifying code
-	; the vblank interrupt jumps here
+	; the vblank interrupt jumps her:b we
 	; this should be enough memory for 
 	; a jp + address
 	; and a reti instruction
@@ -118,18 +118,18 @@ map: .adv 2
 	; map generator settings
 	
 	; the seed used for the current map
-map_gen_seed: .adv 2
+mapgen_seed: .adv 2
 	; ptr to map gen slot flags
 	; this can be used to store previous maps states
 	; to allow the player to return
-map_gen_slot_flags: .adv 2
+mapgen_slot_flags: .adv 2
 
 	; the seed before loading map rng
 	; used as backup
-map_gen_old_seed: .adv 2
+mapgen_game_seed: .adv 2
 	
 	; generated map header
-map_gen_header: .adv map_header_size
+mapgen_header: .adv map_header_size
 	
 	; collision related data
 	; y/x positions
@@ -166,6 +166,13 @@ map_mark_flag: .adv 1
 render_canary: .adv 4
 #endif
 
+; mapgen tile memory
+mapgen_tiles: .adv MAP_TILES
+
+#ifdef DEBUG_CANARY
+mapgen_canary: .adv 4
+#endif
+
 ; tile memory
 .org 0xC800
 
-- 
2.30.2