From 0c918213646734acbbda110dca3fa2e2198b3894 Mon Sep 17 00:00:00 2001
From: Nicholas Bishop <nicholasbishop@gmail.com>
Date: Wed, 14 Mar 2012 06:31:24 +0000
Subject: [PATCH] Add new CCG accessor functions.

ccg_gridsize() converts a level into gridsize, ccg_factor() is for
converting coordinates between different multires levels.
---
 source/blender/blenkernel/BKE_subsurf.h        | 10 ++++++++++
 source/blender/blenkernel/intern/CCGSubSurf.c  | 11 ++++++++++-
 source/blender/blenkernel/intern/subsurf_ccg.c |  1 -
 3 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/source/blender/blenkernel/BKE_subsurf.h b/source/blender/blenkernel/BKE_subsurf.h
index 7f4ff1bf2e3..bc333f8fd66 100644
--- a/source/blender/blenkernel/BKE_subsurf.h
+++ b/source/blender/blenkernel/BKE_subsurf.h
@@ -31,6 +31,9 @@
  *  \ingroup bke
  */
 
+/* struct DerivedMesh is used directly */
+#include "BKE_DerivedMesh.h"
+
 struct DMFlagMat;
 struct DMGridAdjacency;
 struct DMGridData;
@@ -61,6 +64,13 @@ struct DerivedMesh *subsurf_make_derived_from_derived(
 
 void subsurf_calculate_limit_positions(struct Mesh *me, float (*positions_r)[3]);
 
+/* get gridsize from 'level', level must be greater than zero */
+int ccg_gridsize(int level);
+
+/* x/y grid coordinates at 'low_level' can be multiplied by the result
+   of this function to convert to grid coordinates at 'high_level' */
+int ccg_factor(int low_level, int high_level);
+
 /**************************** Internal *****************************/
 
 typedef struct CCGDerivedMesh {
diff --git a/source/blender/blenkernel/intern/CCGSubSurf.c b/source/blender/blenkernel/intern/CCGSubSurf.c
index 7cee0272e4b..f0075217102 100644
--- a/source/blender/blenkernel/intern/CCGSubSurf.c
+++ b/source/blender/blenkernel/intern/CCGSubSurf.c
@@ -8,6 +8,7 @@
 #include <math.h>
 
 #include "CCGSubSurf.h"
+#include "BKE_subsurf.h"
 
 #include "MEM_guardedalloc.h"
 #include "BLO_sys_types.h" // for intptr_t support
@@ -227,7 +228,7 @@ static CCGAllocatorIFC *_getStandardAllocatorIFC(void)
 
 /***/
 
-static int ccg_gridsize(int level)
+int ccg_gridsize(int level)
 {
 	BLI_assert(level > 0);
 	BLI_assert(level <= 31);
@@ -235,6 +236,14 @@ static int ccg_gridsize(int level)
 	return (1 << (level - 1)) + 1;
 }
 
+int ccg_factor(int low_level, int high_level)
+{
+	BLI_assert(low_level > 0 && high_level > 0);
+	BLI_assert(low_level <= high_level);
+
+	return 1 << (high_level - low_level);
+}
+
 static int ccg_edgesize(int level)
 {
 	BLI_assert(level > 0);
diff --git a/source/blender/blenkernel/intern/subsurf_ccg.c b/source/blender/blenkernel/intern/subsurf_ccg.c
index dbce2e144f2..401f678344b 100644
--- a/source/blender/blenkernel/intern/subsurf_ccg.c
+++ b/source/blender/blenkernel/intern/subsurf_ccg.c
@@ -3388,4 +3388,3 @@ void subsurf_calculate_limit_positions(Mesh *me, float (*positions_r)[3])
 
 	dm->release(dm);
 }
-