From 3af0b7fb7378c916612c11f76e5880164497a0d1 Mon Sep 17 00:00:00 2001
From: havoc <havoc@d7cf8633-e32d-0410-b094-e92efae38249>
Date: Fri, 25 Jun 2010 11:53:41 +0000
Subject: [PATCH] added BIH_GetTriangleListForBox function

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@10250 d7cf8633-e32d-0410-b094-e92efae38249
---
 bih.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 bih.h |  2 ++
 2 files changed, 50 insertions(+)

diff --git a/bih.c b/bih.c
index fdda1d6d..58cc0715 100644
--- a/bih.c
+++ b/bih.c
@@ -141,3 +141,51 @@ int BIH_Build(bih_t *bih, int numleafs, bih_leaf_t *leafs, int maxnodes, bih_nod
 	bih->rootnode = BIH_BuildNode(bih, bih->numleafs, bih->leafsort, bih->mins, bih->maxs);
 	return bih->error;
 }
+
+static void BIH_GetTriangleListForBox_Node(const bih_t *bih, int nodenum, int maxtriangles, int *trianglelist, int *numtrianglespointer, const float *mins, const float *maxs)
+{
+	int axis;
+	bih_node_t *node;
+	bih_leaf_t *leaf;
+	while (nodenum >= 0)
+	{
+		node = bih->nodes + nodenum;
+		axis = node->type - BIH_SPLITX;
+		if (mins[axis] < node->backmax)
+		{
+			if (maxs[axis] > node->frontmin)
+				BIH_GetTriangleListForBox_Node(bih, node->front, maxtriangles, trianglelist, numtrianglespointer, mins, maxs);
+			nodenum = node->back;
+			continue;
+		}
+		if (maxs[axis] > node->frontmin)
+		{
+			nodenum = node->front;
+			continue;
+		}
+		// fell between the child groups, nothing here
+		return;
+	}
+	leaf = bih->leafs + (-1-nodenum);
+	if (mins[0] > leaf->maxs[0] || maxs[0] < leaf->mins[0]
+	 || mins[1] > leaf->maxs[1] || maxs[1] < leaf->mins[1]
+	 || mins[2] > leaf->maxs[2] || maxs[2] < leaf->mins[2])
+		return;
+	switch(leaf->type)
+	{
+	case BIH_RENDERTRIANGLE:
+		if (*numtrianglespointer >= maxtriangles)
+			return;
+		trianglelist[(*numtrianglespointer)++] = leaf->itemindex;
+		break;
+	default:
+		break;
+	}
+}
+
+int BIH_GetTriangleListForBox(const bih_t *bih, int maxtriangles, int *trianglelist, const float *mins, const float *maxs)
+{
+	int numtriangles = 0;
+	BIH_GetTriangleListForBox_Node(bih, 0, maxtriangles, trianglelist, &numtriangles, mins, maxs);
+	return numtriangles;
+}
diff --git a/bih.h b/bih.h
index 48a33d11..194a6533 100644
--- a/bih.h
+++ b/bih.h
@@ -80,4 +80,6 @@ bih_t;
 
 int BIH_Build(bih_t *bih, int numleafs, bih_leaf_t *leafs, int maxnodes, bih_node_t *nodes, int *temp_leafsort, int *temp_leafsortscratch);
 
+int BIH_GetTriangleListForBox(const bih_t *bih, int maxtriangles, int *trianglelist, const float *mins, const float *maxs);
+
 #endif
-- 
2.39.2