From 131e34882a97e0b24905e23ce1a730157f67d234 Mon Sep 17 00:00:00 2001
From: jeffman <jefferbrecht@gmail.com>
Date: Sat, 18 Mar 2017 17:39:56 -0400
Subject: [PATCH] Erase tiles for scrolling text

---
 m2-hack.asm        |  2 ++
 m2-vwf-entries.asm | 49 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 51 insertions(+)

diff --git a/m2-hack.asm b/m2-hack.asm
index a7a8bd8..a8a92fd 100644
--- a/m2-hack.asm
+++ b/m2-hack.asm
@@ -292,7 +292,9 @@ b       $80C9788
 // CA4BC hacks (scroll text)
 //---------------------------------------------------------
 
+org $80CA55E; bl m2_vwf_entries.ca4bc_erase_tile_short
 org $80CA60E; bl m2_vwf_entries.ca4bc_copy_tile_up
+org $80CA626; bl m2_vwf_entries.ca4bc_erase_tile
 
 //---------------------------------------------------------
 // D2E94 hacks (print party character name)
diff --git a/m2-vwf-entries.asm b/m2-vwf-entries.asm
index a365671..4ccb18b 100644
--- a/m2-vwf-entries.asm
+++ b/m2-vwf-entries.asm
@@ -642,3 +642,52 @@ bne     .ca4bc_nonblank_to_nonblank
 
 .ca4bc_end:
 pop     {r4-r7,pc}
+
+//==============================================================================
+// Erase tile (for short windows)
+// r2: 100
+// r4: (x << 16) (relative)
+// r5: dest tilemap
+// r6: window
+// r8: y (dest, relative)
+.ca4bc_erase_tile_short:
+push    {lr}
+add     sp,#-12
+
+// Clobbered code
+orr     r0,r1 // 0xE2FF
+strh    r0,[r5,#0] // dest tilemap
+
+// We need to erase the pixels
+.ca4bc_erase_tile_common:
+mov     r0,sp
+strh    r2,[r0,#8] // tile offset
+ldr     r2,=#0x44444444
+str     r2,[r0,#4] // empty row of pixels
+ldrh    r2,[r6,#0x22]
+lsl     r2,r2,#16
+add     r2,r2,r4
+lsr     r2,r2,#16 // x
+ldrh    r1,[r6,#0x24]
+add     r1,r8 // y
+strh    r2,[r0,#0]
+strh    r1,[r0,#2]
+bl      m2_vwf.clear_tile_internal
+
+add     sp,#12
+pop     {pc}
+
+//==============================================================================
+// Erase tile
+.ca4bc_erase_tile:
+push    {lr}
+add     sp,#-12
+
+// Clobbered code
+ldrh    r1,[r1,#0]
+strh    r1,[r5,#0]
+
+// We need to erase the pixels
+ldr     r2,=#0x30051EC
+ldrh    r2,[r2,#0]
+b       .ca4bc_erase_tile_common