From 27f14e99c29b48545a2688036929bd70e2b7c45c Mon Sep 17 00:00:00 2001
From: Matthew <matthew@sleepy.day>
Date: Sat, 13 Sep 2025 16:43:35 +1000
Subject: [PATCH] make tree recurse without recursive functions

---
 src/editor/ui.d | 84 ++++++++++++++++++++++++++++++++-----------------
 1 file changed, 56 insertions(+), 28 deletions(-)

diff --git a/src/editor/ui.d b/src/editor/ui.d
index eb80b2c..c8c5c1a 100644
--- a/src/editor/ui.d
+++ b/src/editor/ui.d
@@ -446,75 +446,103 @@ DrawNodes(UIItem* item)
 void
 CalcFixedSizes(UIItem* item)
 {
-	if (!Nil(item))
+	for(UIItem* i = item; !Nil(i); i = Recurse(i))
 	{
 		static foreach(axis; A2D.min .. A2D.max)
 		{
-			if (item.size_info[axis].type == ST.Pixels)
+			if (i.size_info[axis].type == ST.Pixels)
 			{
-				item.size.v[axis] = item.size_info[axis].value + item.adjustment.v[axis];
+				i.size.v[axis] = i.size_info[axis].value + i.adjustment.v[axis];
 			}
 		}
-
-		CalcFixedSizes(item.first);
-		CalcFixedSizes(item.next);
 	}
 }
 
 void
 CalcPercentageSizes(UIItem* item)
 {
-	if (!Nil(item))
+	for(UIItem* i = item; !Nil(i); i = Recurse(i))
 	{
 		static foreach(axis; A2D.min .. A2D.max)
 		{
-			if (item.size_info[axis].type == ST.Percentage)
+			if (i.size_info[axis].type == ST.Percentage)
 			{
-				item.size.v[axis] = (item.parent.size.v[axis]*item.size_info[axis].value) + item.adjustment.v[axis];
+				i.size.v[axis] = (i.parent.size.v[axis]*i.size_info[axis].value) + i.adjustment.v[axis];
 			}
 		}
-
-		CalcPercentageSizes(item.first);
-		CalcPercentageSizes(item.next);
 	}
 }
 
 void
-CalcPositions(alias axis)(UIItem* item, f32 pos = 0.0)
+CalcPositions(alias axis)(UIItem* item)
 {
-	if (!Nil(item))
+	f32 pos = 0.0;
+	for(UIItem* i = item; !Nil(i);)
 	{
-		f32 end_pos = pos + item.size.v[axis];
-		item.rect.vec0.v[axis] = pos;
-		item.rect.vec1.v[axis] = end_pos;
+		f32 end_pos = pos + i.size.v[axis];
+		i.rect.vec0.v[axis] = pos;
+		i.rect.vec1.v[axis] = end_pos;
 
-		f32 next_pos = item.parent.layout_axis == axis ? end_pos : pos;
+		f32 next_pos = i.parent.layout_axis == axis ? end_pos : pos;
 
-		CalcPositions!(axis)(item.first, pos);
-		CalcPositions!(axis)(item.next, next_pos);
+		if (!Nil(i.first))
+		{
+			i = i.first;
+		}
+		else if (!Nil(i.next))
+		{
+			i = i.next;
+			pos = next_pos;
+		}
+		else if (!Nil(i.parent.next))
+		{
+			i = i.parent.next;
+			pos = i.parent.layout_axis == axis ? i.prev.rect.vec1.v[axis] : i.prev.rect.vec0.v[axis];
+		}
+		else
+		{
+			break;
+		}
 	}
 }
 
 void
 DrawUI(UICtx* ctx, UIItem* item)
 {
-	if (!Nil(item))
+	for(UIItem* i = item; !Nil(i); i = Recurse(i))
 	{
-		if (item.flags & UIF.DrawBackground)
+		if (i.flags & UIF.DrawBackground)
 		{
-			DrawRect(ctx, item);
+			DrawRect(ctx, i);
 		}
 
-		if (item.flags & UIF.DrawText)
+		if (i.flags & UIF.DrawText)
 		{
-			DrawLine(item);
+			DrawLine(i);
 		}
-
-		DrawUI(ctx, item.first);
-		DrawUI(ctx, item.next);
 	}
 }
 
+UIItem*
+Recurse(UIItem* item)
+{
+	UIItem* result = g_UI_NIL;
+	if (!Nil(item.first))
+	{
+		result = item.first;
+	}
+	else if (!Nil(item.next))
+	{
+		result = item.next;
+	}
+	else if (!Nil(item.parent.next))
+	{
+		result = item.parent.next;
+	}
+
+	return result;
+}
+
 void
 BuildItem(UIItem* item, UISize size_x, UISize size_y, UIFlags properties)
 {