From: Toni Wilen <twilen@winuae.net>
Date: Sat, 21 Nov 2020 12:43:57 +0000 (+0200)
Subject: Fix HAM corruption if filter horizontal start was after HAM horizontal start.
X-Git-Tag: 4900~247
X-Git-Url: https://git.unchartedbackwaters.co.uk/w/?a=commitdiff_plain;h=7688ae0e8464c1bcdf023dcd0e2f751d6ac48f01;p=francis%2Fwinuae.git

Fix HAM corruption if filter horizontal start was after HAM horizontal start.
---

diff --git a/drawing.cpp b/drawing.cpp
index 8da58b10..69b5b98e 100644
--- a/drawing.cpp
+++ b/drawing.cpp
@@ -862,6 +862,7 @@ static int sprite_playfield_start, sprite_end;
 static int may_require_hard_way;
 static int linetoscr_diw_start, linetoscr_diw_end;
 static int native_ddf_left, native_ddf_right;
+static int hamleftborderhidden;
 
 static int pixels_offset;
 static int src_pixel;
@@ -1064,9 +1065,12 @@ static void pfield_init_linetoscr (bool border)
 	pixels_offset = MAX_PIXELS_PER_LINE - ddf_left;
 
 	leftborderhidden = playfield_start - native_ddf_left2;
+	hamleftborderhidden = 0;
 
-	if (hblank_left_start > playfield_start)
+	if (hblank_left_start > playfield_start) {
 		leftborderhidden += hblank_left_start - playfield_start;
+		hamleftborderhidden = hblank_left_start - playfield_start;
+	}
 
 	src_pixel = MAX_PIXELS_PER_LINE + res_shift_from_window(leftborderhidden);
 
@@ -2092,9 +2096,9 @@ static unsigned int ham_lastcolor;
  */
 static void init_ham_decoding (void)
 {
-	int unpainted_amiga = unpainted;
+	int unpainted_amiga = unpainted + hamleftborderhidden;
 
-	ham_decode_pixel = src_pixel;
+	ham_decode_pixel = src_pixel - hamleftborderhidden;
 	ham_lastcolor = color_reg_get (&colors_for_drawing, 0);
 
 	if (!bplham) {