From: Toni Wilen <twilen@winuae.net>
Date: Sat, 1 Nov 2025 13:50:20 +0000 (+0200)
Subject: Clear chipset frame when entering genlock no sync state.
X-Git-Url: https://git.unchartedbackwaters.co.uk/w/?a=commitdiff_plain;h=a7a5613944f7842a7302d40c592d1927c25bcce8;p=francis%2Fwinuae.git

Clear chipset frame when entering genlock no sync state.
---

diff --git a/custom.cpp b/custom.cpp
index 2e50b0c9..b2b8ca9f 100644
--- a/custom.cpp
+++ b/custom.cpp
@@ -11265,6 +11265,9 @@ static void start_sync_imm_handler(void)
 
 static void vsync_nosync(void)
 {
+	if (!nosignal_trigger) {
+		denise_clearbuffers();
+	}
 	nosignal_trigger = true;
 	linear_vpos = 0;
 	vsync_handler_post();
diff --git a/drawing.cpp b/drawing.cpp
index 533c16d3..6c185acb 100644
--- a/drawing.cpp
+++ b/drawing.cpp
@@ -2321,6 +2321,21 @@ void freevidbuffer(int monid, struct vidbuffer *buf)
 	}
 }
 
+void denise_clearbuffers(void)
+{
+	int monid = 0;
+	struct amigadisplay *ad = &adisplays[monid];
+	struct vidbuf_description *vidinfo = &ad->gfxvidinfo;
+	if (vidinfo->outbuffer && vidinfo->outbuffer->locked) {
+		struct vidbuffer *dst = vidinfo->outbuffer;
+		uae_u8 *p = dst->bufmem;
+		for (int y = 0; y < dst->height_allocated; y++) {
+			memset (p, 0, dst->width_allocated * dst->pixbytes);
+			p += dst->rowbytes;
+		}
+	}
+}
+
 void reset_drawing(void)
 {
 	custom_end_drawing();
diff --git a/include/drawing.h b/include/drawing.h
index 4416be69..7b2bc3c3 100644
--- a/include/drawing.h
+++ b/include/drawing.h
@@ -197,5 +197,6 @@ void set_drawbuffer(void);
 int gethresolution(void);
 void denise_update_reg_queue(uae_u16 reg, uae_u16 v, uae_u32 linecnt);
 void denise_store_restore_registers_queue(bool store, uae_u32 linecnt);
+void denise_clearbuffers(void);
 
 #endif /* UAE_DRAWING_H */