From d16ba90856e1111261818fef2b2677f1ec7cad05 Mon Sep 17 00:00:00 2001
From: Ian Curtis <i.curtis@gmail.com>
Date: Wed, 1 Nov 2023 16:01:13 +0000
Subject: [PATCH] Update comments for the culling node function. gm_matthew
 worked out that the last 2 bits of the model scale float appear to be control
 bits for disable culling and valid model scale. Strange logic but the line of
 sight (LOS) function does something similar by re-using float bits for
 control words.

---
 Src/Graphics/New3D/New3D.cpp | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/Src/Graphics/New3D/New3D.cpp b/Src/Graphics/New3D/New3D.cpp
index 1a5bb2e..6d2816c 100644
--- a/Src/Graphics/New3D/New3D.cpp
+++ b/Src/Graphics/New3D/New3D.cpp
@@ -561,7 +561,9 @@ bool CNew3D::DrawModel(UINT32 modelAddr)
 
 	0x01, 0x02 only present on Step 2 +
 
-	0x01:   xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx	Model scale(float)
+	0x01:   xxxxxxxx xxxxxxxx xxxxxxxx xxxxxx--	Model scale (float32) last 2 bits are control words
+			-------- -------- -------- ------x- Disable culling
+			-------- -------- -------- -------x	Valid model scale
 	0x02 :	-------- -------- x------- --------	Texture replace
 			-------- -------- -x------ --------	Switch bank
 			-------- -------- --xxxxxx x-------	X offset
@@ -570,6 +572,23 @@ bool CNew3D::DrawModel(UINT32 modelAddr)
 	0x03 :	xxxxxxxx xxxxx--- -------- --------	Color table address 1
 			-------- -----xxx xxxx---- --------	LOD table pointer
 			-------- -------- ----xxxx xxxxxxxx	Node matrix
+
+	0x04:   Translation X coordinate
+	0x05:   Translation Y coordinate
+	0x06:   Translation Z coordinate
+
+	0x07:   xxxx---- -------- -------- -------- Color table address 2
+			-----x-- -------- -------- -------- Sibling table
+			------x- -------- -------- -------- Point
+			-------x -------- -------- -------- Leaf node
+			-------- xxxxxxxx xxxxxxxx xxxxxxxx Child pointer
+
+	0x08:   xxxxxxx- -------- -------- -------- Color table address 3
+			-------x -------- -------- -------- Null sibling
+			-------- xxxxxxxx xxxxxxxx xxxxxxxx Sibling pointer
+
+	0x09:   xxxxxxxx xxxxxxxx -------- -------- Blend radius
+			-------- -------- xxxxxxxx xxxxxxxx Culling radius
 */
 
 void CNew3D::DescendCullingNode(UINT32 addr)
@@ -597,6 +616,8 @@ void CNew3D::DescendCullingNode(UINT32 addr)
 		return;
 	}
 
+	printf("scale %x %f\n", node[1], Util::Uint32AsFloat(node[1]));
+
 	// Extract known fields
 	nodeType		= (NodeType)(node[0x00] & 3);
 	child1Ptr		= node[0x07 - m_offset] & 0x7FFFFFF;	// mask colour table bits