Gradually turn durability icon from gold to red

Source/control.cpp

@@ -277,9 +277,12 @@ int CapStatPointsToAdd(int remainingStatPoints, const Player &player, CharacterA
 
 int DrawDurIcon4Item(const Surface &out, Item &pItem, int x, int c)
 {
+	const int durabilityThresholdGold = 5;
+	const int durabilityThresholdRed = 2;
+
 	if (pItem.isEmpty())
 		return x;
-	if (pItem._iDurability > 5)
+	if (pItem._iDurability > durabilityThresholdGold)
 		return x;
 	if (c == 0) {
 		switch (pItem._itype) {
@@ -304,10 +307,27 @@ int DrawDurIcon4Item(const Surface &out, Item &pItem, int x, int c)
 			break;
 		}
 	}
-	if (pItem._iDurability > 2)
-		c += 8;
-	ClxDraw(out, { x, -17 + GetMainPanel().position.y }, (*pDurIcons)[c]);
-	return x - 32 - 8;
+
+	// Calculate how much of the icon should be gold and red
+	int height = (*pDurIcons)[c].height(); // Height of durability icon CEL
+	int partition = 0;
+	if (pItem._iDurability > durabilityThresholdRed) {
+		int current = pItem._iDurability - durabilityThresholdRed;
+		partition = (height * current) / (durabilityThresholdGold - durabilityThresholdRed);
+	}
+
+	// Draw icon
+	int y = -17 + GetMainPanel().position.y;
+	if (partition > 0) {
+		const Surface stenciledBuffer = out.subregionY(y - partition, partition);
+		ClxDraw(stenciledBuffer, { x, partition }, (*pDurIcons)[c + 8]); // Gold icon
+	}
+	if (partition != height) {
+		const Surface stenciledBuffer = out.subregionY(y - height, height - partition);
+		ClxDraw(stenciledBuffer, { x, height }, (*pDurIcons)[c]); // Red icon
+	}
+
+	return x - (*pDurIcons)[c].height() - 8; // Add in spacing for the next durability icon
 }
 
 struct TextCmdItem {