From 52152a3a12f36f91ace52b31ab9f0c129b8cd19e Mon Sep 17 00:00:00 2001
From: Jeffrey Pfau <jeffrey@endrift.com>
Date: Sun, 14 Feb 2016 11:26:45 -0800
Subject: [PATCH] GB Video: Fix window underflow

---
 src/gb/renderers/software.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/gb/renderers/software.c b/src/gb/renderers/software.c
index dff2089f6..9074c01fa 100644
--- a/src/gb/renderers/software.c
+++ b/src/gb/renderers/software.c
@@ -175,6 +175,9 @@ static void GBVideoSoftwareRendererDrawBackground(struct GBVideoSoftwareRenderer
 	}
 	int topY = (((y + sy) >> 3) & 0x1F) * 0x20;
 	int bottomY = (y + sy) & 7;
+	if (startX < 0) {
+		startX = 0;
+	}
 	int x;
 	for (x = startX; x < endX; ++x) {
 		int topX = ((x + sx) >> 3) & 0x1F;
@@ -204,6 +207,9 @@ static void GBVideoSoftwareRendererDrawObj(struct GBVideoSoftwareRenderer* rende
 	if (obj->x - 8 > startX) {
 		startX = obj->x - 8;
 	}
+	if (startX < 0) {
+		startX = 0;
+	}
 	uint8_t* data = renderer->d.vram;
 	int tileOffset = 0;
 	int bottomY;