From 3f31145d2971d973d401878e9223de44ef3952fe Mon Sep 17 00:00:00 2001
From: Campbell Barton <ideasman42@gmail.com>
Date: Tue, 24 Jan 2012 20:58:43 +0000
Subject: [PATCH] define to enable tesselate to quads, this way files from
 trunk tesselate back into their original geometry with the same face order.

this will be needed for tangents and most likely hair if its to load correctly from trunk.

disabled for now until this is working correctly - hair still needs more work.
---
 source/blender/blenkernel/intern/mesh.c | 65 ++++++++++++++++++++++---
 1 file changed, 59 insertions(+), 6 deletions(-)

diff --git a/source/blender/blenkernel/intern/mesh.c b/source/blender/blenkernel/intern/mesh.c
index 9ac44aa4651..c548115e5ab 100644
--- a/source/blender/blenkernel/intern/mesh.c
+++ b/source/blender/blenkernel/intern/mesh.c
@@ -2224,6 +2224,10 @@ int mesh_recalcTesselation(CustomData *fdata,
 	 * and calling the fill function */
 
 #define USE_TESSFACE_SPEEDUP
+// #define USE_TESSFACE_QUADS // NEEDS FURTHER TESTING
+
+#define TESSFACE_SCANFILL (1<<0)
+#define TESSFACE_IS_QUAD  (1<<1)
 
 	MPoly *mp, *mpoly;
 	MLoop *ml, *mloop;
@@ -2278,17 +2282,43 @@ int mesh_recalcTesselation(CustomData *fdata,
 		                     poly_orig_index[poly_index]);                    \
 		}                                                                     \
 
+/* ALMOST IDENTICAL TO DEFINE ABOVE (see EXCEPTION) */
+#define ML_TO_MF_QUAD()                                                       \
+		BLI_array_growone(mface_to_poly_map);                                 \
+		BLI_array_growone(mface);                                             \
+		mface_to_poly_map[mface_index] = poly_index;                          \
+		mf= &mface[mface_index];                                              \
+		/* set loop indices, transformed to vert indices later */             \
+		mf->v1 = mp->loopstart + 0; /* EXCEPTION */                           \
+		mf->v2 = mp->loopstart + 1; /* EXCEPTION */                           \
+		mf->v3 = mp->loopstart + 2; /* EXCEPTION */                           \
+		mf->v4 = mp->loopstart + 3; /* EXCEPTION */                           \
+		mf->mat_nr = mp->mat_nr;                                              \
+		mf->flag = mp->flag;                                                  \
+		if (poly_orig_index) {                                                \
+			BLI_array_append(mface_orig_index,                                \
+		                     poly_orig_index[poly_index]);                    \
+		}                                                                     \
+		mf->edcode |= TESSFACE_IS_QUAD; /* EXCEPTION */                       \
+
+
 		else if (mp->totloop == 3) {
 			ml = mloop + mp->loopstart;
 			ML_TO_MF(0, 1, 2)
 			mface_index++;
 		}
 		else if (mp->totloop == 4) {
+#ifdef USE_TESSFACE_QUADS
+			ml = mloop + mp->loopstart;
+			ML_TO_MF_QUAD()
+			mface_index++;
+#else
 			ml = mloop + mp->loopstart;
 			ML_TO_MF(0, 1, 2)
 			mface_index++;
 			ML_TO_MF(0, 2, 3)
 			mface_index++;
+#endif
 		}
 #endif /* USE_TESSFACE_SPEEDUP */
 		else {
@@ -2335,7 +2365,7 @@ int mesh_recalcTesselation(CustomData *fdata,
 					mf->flag = mp->flag;
 
 #ifdef USE_TESSFACE_SPEEDUP
-					mf->edcode = 1; /* tag for sorting loop indicies */
+					mf->edcode |= TESSFACE_SCANFILL; /* tag for sorting loop indicies */
 #endif
 
 					if (poly_orig_index) {
@@ -2383,9 +2413,13 @@ int mesh_recalcTesselation(CustomData *fdata,
 	mf = mface;
 	for (mface_index=0; mface_index < totface; mface_index++, mf++) {
 
+#ifdef USE_TESSFACE_QUADS
+		const int mf_len = mf->edcode & TESSFACE_IS_QUAD ? 4 : 3;
+#endif
+
 #ifdef USE_TESSFACE_SPEEDUP
 		/* skip sorting when not using ngons */
-		if (UNLIKELY(mf->edcode == 1))
+		if (UNLIKELY(mf->edcode & TESSFACE_SCANFILL))
 #endif
 		{
 			/* sort loop indices to ensure winding is correct */
@@ -2396,24 +2430,43 @@ int mesh_recalcTesselation(CustomData *fdata,
 			if (mf->v1 > mf->v2) SWAP(int, mf->v1, mf->v2);
 			if (mf->v2 > mf->v3) SWAP(int, mf->v2, mf->v3);
 			if (mf->v1 > mf->v2) SWAP(int, mf->v1, mf->v2);
+		}
 
-#ifdef USE_TESSFACE_SPEEDUP
-			mf->edcode = 0;
+		/* end abusing the edcode */
+#if defined(USE_TESSFACE_QUADS) || defined(USE_TESSFACE_SPEEDUP)
+		mf->edcode = 0;
 #endif
-		}
+
 
 		lindex[0] = mf->v1;
 		lindex[1] = mf->v2;
 		lindex[2] = mf->v3;
+#ifdef USE_TESSFACE_QUADS
+		if (mf_len == 4) lindex[2] = mf->v3;
+#endif
 
 		/*transform loop indices to vert indices*/
 		mf->v1 = mloop[mf->v1].v;
 		mf->v2 = mloop[mf->v2].v;
 		mf->v3 = mloop[mf->v3].v;
+#ifdef USE_TESSFACE_QUADS
+		if (mf_len == 4) mf->v4 = mloop[mf->v4].v;
+#endif
 
 		mesh_loops_to_mface_corners(fdata, ldata, pdata,
-		                            lindex, mface_index, mface_to_poly_map[mface_index], 3,
+		                            lindex, mface_index, mface_to_poly_map[mface_index],
+#ifdef USE_TESSFACE_QUADS
+		                            mf_len,
+#else
+		                            3,
+#endif
 		                            numTex, numCol, hasWCol);
+
+
+#ifdef USE_TESSFACE_QUADS
+		test_index_face(mf, fdata, mface_index, 4);
+#endif
+
 	}
 
 	return totface;
-- 
2.28.0