From e51058998b495efd72d9e522779f413aab5e0462 Mon Sep 17 00:00:00 2001
From: zsknight <>
Date: Wed, 9 May 2001 04:00:47 +0000
Subject: [PATCH] Added main screen clip layer (Illusion of Gaia fix)

---
 zsnes/src/video/newgfx16.asm | 101 ++++++++++++++++++++++++++++++++++-
 1 file changed, 100 insertions(+), 1 deletion(-)

diff --git a/zsnes/src/video/newgfx16.asm b/zsnes/src/video/newgfx16.asm
index 6d8c036b..2e79a698 100644
--- a/zsnes/src/video/newgfx16.asm
+++ b/zsnes/src/video/newgfx16.asm
@@ -1355,6 +1355,7 @@ NEWSYM StartDrawNewGfx16b
     mov byte[WindowRedraw],1
     sub dword[endlinet],8
 
+
     ; Clear video memory
 ;    mov edi,[vidbuffer]
 ;    xor eax,eax
@@ -1771,6 +1772,8 @@ NEWSYM StartDrawNewGfx16b
     mov dword[mode0ads],40404040h
     Procbg3pr1b16b 2, drawbg3linepr116b, drawbg3tilepr116b, prdatc, ngmain, 4h
 .nodobg3mb2
+
+    call MainScreenClip
     call ProcessTransparencies
 .dontdraw
     xor ebx,ebx
@@ -2563,6 +2566,7 @@ NEWSYM drawsprngw16b
 .main
     normalwsprng16b sprdrawprawb16bng,sprdrawprbwb16bng
 
+
 drawsprng16bt:
     test byte[scadtng+ebx],10h
     jz near drawsprng16bnt
@@ -2740,7 +2744,6 @@ drawsprngw16bmsnthr:
     xor edi,edi
     normalwsprng16b sprdrawprawb16bngmsnthr,sprdrawprbwb16bngmsnthr
 
-
 ProcessTransparencies:
     cmp byte[NGNoTransp],0
     je .yestransp
@@ -3413,3 +3416,99 @@ NEWSYM HalfTransB, dd 00001000010000010000100001000001b,000010000100000100001000
 NEWSYM HalfTransC, dd 11110111100111101111011110011110b,11110111100111101111011110011110b
 NEWSYM NGNoTransp, dd 0
 NEWSYM NewGfx16AsmEnd
+
+
+MainScreenClip:
+    mov esi,[vidbuffer]
+    add esi,16*2+288*2
+    mov ebx,1
+.nextline
+    mov al,byte[scadsng+ebx]
+    test al,0C0h
+    jz near .notthisone
+    push esi
+    push ebx
+    and al,0C0h
+    cmp al,0C0h
+    jne .notentire
+    mov ebx,[UnusedBit]
+    mov ecx,256
+    mov edx,256
+    jmp .startclipping
+.notentire
+
+    mov dword[ngwinen],0
+    test byte[winbg1enval+ebx+5*256],0Ah
+    jz .nowindowing
+    push eax
+    push ebx
+    mov al,[winlogicaval+ebx*2+1]
+    shr al,2
+    and al,03h
+    mov [nglogicval],al
+    mov eax,ebx
+    add ebx,5*256
+    call BuildWindow
+;ngwintable
+    pop ebx
+    pop eax
+.nowindowing
+
+    mov ebx,[UnusedBit]
+    mov edx,256
+    cmp dword[ngwinen],0
+    jne .windowenabled
+    cmp al,80h
+    je near .finclipping
+    mov ecx,256
+    jmp .startclipping
+.windowenabled
+    cmp al,80h
+    je near .outsideclipping
+    mov edi,ngwintable
+    mov ecx,[edi]
+    add edi,4
+    or ecx,ecx
+    jnz near .startclipping
+    mov ecx,[edi]
+    add edi,4
+    jmp .noclipping
+.outsideclipping
+    mov edi,ngwintable
+    mov ecx,[edi]
+    add edi,4
+    or ecx,ecx
+    jnz .noclipping
+    mov ecx,[edi]
+    add edi,4
+    jmp .startclipping
+
+.startclipping
+    and word[esi],bx
+    or word[esi+75036*2],bx
+    add esi,2
+    dec edx
+    jz .finclipping
+    dec ecx
+    jnz .startclipping
+    mov ecx,[edi]
+    add edi,4
+.noclipping
+    sub edx,ecx
+    jz .finclipping
+    jc .finclipping
+    add ecx,ecx
+    add esi,ecx
+    mov ecx,[edi]
+    add edi,4
+    jmp .startclipping
+
+.finclipping
+    pop ebx
+    pop esi
+.notthisone
+    inc ebx
+    add esi,288*2
+    cmp [resolutn],bx
+    jne near .nextline
+    ret