Freestyle: View map caching.

New render layer option named "View map cache" is added to reuse a
previously computed view map for subsequent rendering.  The cache is
automatically updated when the mesh geometry of the input 3D scene has
been changed.

This functionality offers a major performance boost for Freestyle
animation rendering when camera-space mesh geometry is static, as well
as for repeated still renders with updates of line stylization options.

Although the "View map cache" toggle is a render layer option, the cache
memory is shared by all render layers and scenes.  This means that if
Freestyle is used for two or more render layers (possibly in different
scenes through the compositor), then the cached view map for one render
layer is replaced by a new view map for another render layer and hence
no performance gain is expected.

11 files changed, 201 insertions, 38 deletions

diff --git a/source/blender/freestyle/CMakeLists.txt b/source/blender/freestyle/CMakeLists.txt
index c94a5ac9f92..bfd1c17df7d 100644
--- a/source/blender/freestyle/CMakeLists.txt
+++ b/source/blender/freestyle/CMakeLists.txt
@@ -412,6 +412,8 @@ set(SRC
 	intern/scene_graph/OrientedLineRep.h
 	intern/scene_graph/Rep.cpp
 	intern/scene_graph/Rep.h
+	intern/scene_graph/SceneHash.cpp
+	intern/scene_graph/SceneHash.h
 	intern/scene_graph/ScenePrettyPrinter.cpp
 	intern/scene_graph/ScenePrettyPrinter.h
 	intern/scene_graph/SceneVisitor.cpp
diff --git a/source/blender/freestyle/FRS_freestyle.h b/source/blender/freestyle/FRS_freestyle.h
index fc9fc35e410..1815883bf0d 100644
--- a/source/blender/freestyle/FRS_freestyle.h
+++ b/source/blender/freestyle/FRS_freestyle.h
@@ -48,6 +48,7 @@ int FRS_is_freestyle_enabled(struct SceneRenderLayer *srl);
 void FRS_init_stroke_rendering(struct Render *re);
 struct Render *FRS_do_stroke_rendering(struct Render *re, struct SceneRenderLayer *srl, int render);
 void FRS_finish_stroke_rendering(struct Render *re);
+void FRS_free_view_map_cache();
 void FRS_composite_result(struct Render *re, struct SceneRenderLayer *srl, struct Render *freestyle_render);
 void FRS_exit(void);
 
diff --git a/source/blender/freestyle/intern/application/Controller.cpp b/source/blender/freestyle/intern/application/Controller.cpp
index 176199600ac..a7f936ff171 100644
--- a/source/blender/freestyle/intern/application/Controller.cpp
+++ b/source/blender/freestyle/intern/application/Controller.cpp
@@ -118,6 +118,7 @@ Controller::Controller()
 	_Canvas = new AppCanvas;
 
 	_inter = new PythonInterpreter();
+	_EnableViewMapCache = false;
 	_EnableQI = true;
 	_EnableFaceSmoothness = false;
 	_ComputeRidges = true;
@@ -212,6 +213,19 @@ void Controller::setContext(bContext *C)
 	py_inter->setContext(C);
 }
 
+bool Controller::hitViewMapCache()
+{
+	if (!_EnableViewMapCache) {
+		return false;
+	}
+	real hashCode = sceneHashFunc.getValue();
+	if (prevSceneHash == hashCode) {
+		return (NULL != _ViewMap);
+	}
+	prevSceneHash = hashCode;
+	return false;
+}
+
 int Controller::LoadMesh(Render *re, SceneRenderLayer *srl)
 {
 	BlenderFileLoader loader(re, srl);
@@ -242,6 +256,7 @@ int Controller::LoadMesh(Render *re, SceneRenderLayer *srl)
 	if (G.debug & G_DEBUG_FREESTYLE) {
 		cout << "Scene loaded" << endl;
 		printf("Mesh cleaning    : %lf\n", duration);
+		printf("View map cache   : %s\n", _EnableViewMapCache ? "enabled" : "disabled");
 	}
 	_SceneNumFaces += loader.numFacesRead();
 
@@ -263,6 +278,22 @@ int Controller::LoadMesh(Render *re, SceneRenderLayer *srl)
 	if (_pRenderMonitor->testBreak())
 		return 0;
 
+	if (_EnableViewMapCache) {
+		sceneHashFunc.reset();
+		blenderScene->accept(sceneHashFunc);
+		if (G.debug & G_DEBUG_FREESTYLE) {
+			printf("Scene hash       : %.16e\n", sceneHashFunc.getValue());
+		}
+		if (hitViewMapCache()) {
+			ClearRootNode();
+			return 0;
+		}
+		else {
+			delete _ViewMap;
+			_ViewMap = NULL;
+		}
+	}
+
 	_Chrono.start();
 
 	WXEdgeBuilder wx_builder;
@@ -357,7 +388,7 @@ void Controller::DeleteWingedEdge()
 	_minEdgeSize = DBL_MAX;
 }
 
-void Controller::DeleteViewMap()
+void Controller::DeleteViewMap(bool freeCache)
 {
 	_pView->DetachSilhouette();
 	if (NULL != _SilhouetteNode) {
@@ -387,14 +418,15 @@ void Controller::DeleteViewMap()
 
 	_pView->DetachDebug();
 	if (NULL != _DebugNode) {
-	int ref = _DebugNode->destroy();
+		int ref = _DebugNode->destroy();
 		if (0 == ref)
 			_DebugNode->addRef();
 	}
 
-	if (NULL != _ViewMap) {
+	if ((freeCache || !_EnableViewMapCache) && NULL != _ViewMap) {
 		delete _ViewMap;
 		_ViewMap = NULL;
+		prevSceneHash = -1.0;
 	}
 }
 
@@ -403,40 +435,7 @@ void Controller::ComputeViewMap()
 	if (!_ListOfModels.size())
 		return;
 
-	if (NULL != _ViewMap) {
-		delete _ViewMap;
-		_ViewMap = NULL;
-	}
-
-	_pView->DetachDebug();
-	if (NULL != _DebugNode) {
-		int ref = _DebugNode->destroy();
-		if (0 == ref)
-			_DebugNode->addRef();
-	}
-
-	_pView->DetachSilhouette();
-	if (NULL != _SilhouetteNode) {
-		int ref = _SilhouetteNode->destroy();
-		if (0 == ref)
-			delete _SilhouetteNode;
-	}
-
-#if 0
-	if (NULL != _ProjectedSilhouette) {
-		int ref = _ProjectedSilhouette->destroy();
-		if (0 == ref)
-			delete _ProjectedSilhouette;
-	}
-
-	if (NULL != _VisibleProjectedSilhouette) {
-		int ref = _VisibleProjectedSilhouette->destroy();
-		if (0 == ref) {
-			delete _VisibleProjectedSilhouette;
-			_VisibleProjectedSilhouette = NULL;
-		}
-	}
-#endif
+	DeleteViewMap(true);
 
 	// retrieve the 3D viewpoint and transformations information
 	//----------------------------------------------------------
@@ -763,6 +762,16 @@ int Controller::getVisibilityAlgo()
 	return FREESTYLE_ALGO_ADAPTIVE_TRADITIONAL;
 }
 
+void Controller::setViewMapCache(bool iBool)
+{
+	_EnableViewMapCache = iBool;
+}
+
+bool Controller::getViewMapCache() const
+{
+	return _EnableViewMapCache;
+}
+
 void Controller::setQuantitativeInvisibility(bool iBool)
 {
 	_EnableQI = iBool;
diff --git a/source/blender/freestyle/intern/application/Controller.h b/source/blender/freestyle/intern/application/Controller.h
index f5e50347d0f..84ee3382612 100644
--- a/source/blender/freestyle/intern/application/Controller.h
+++ b/source/blender/freestyle/intern/application/Controller.h
@@ -32,6 +32,7 @@
 
 //#include "ConfigIO.h"
 #include "../geometry/FastGrid.h"
+#include "../scene_graph/SceneHash.h"
 #include "../system/Interpreter.h"
 #include "../system/ProgressBar.h"
 #include "../system/Precision.h"
@@ -96,7 +97,7 @@ public:
 	void Clear();
 	void ClearRootNode();
 	void DeleteWingedEdge();
-	void DeleteViewMap();
+	void DeleteViewMap(bool freeCache = false);
 	void toggleLayer(unsigned index, bool iDisplay);
 	void setModified(unsigned index, bool iMod);
 	void resetModified(bool iMod=false);
@@ -118,6 +119,8 @@ public:
 	void setVisibilityAlgo(int algo);
 	int getVisibilityAlgo();
 
+	void setViewMapCache(bool iBool);
+	bool getViewMapCache() const;
 	void setQuantitativeInvisibility(bool iBool); // if true, we compute quantitativeInvisibility
 	bool getQuantitativeInvisibility() const;
 	void setFaceSmoothness(bool iBool);
@@ -144,6 +147,8 @@ public:
 	void setModulesDir(const string& dir);
 	string getModulesDir() const;
 
+	bool hitViewMapCache();
+
 	void resetInterpreter();
 
 public:
@@ -231,6 +236,7 @@ private:
 	string _help_index;
 	string _browser_cmd;
 
+	bool _EnableViewMapCache;
 	bool _EnableQI;
 	bool _EnableFaceSmoothness;
 	bool _ComputeRidges;
@@ -244,6 +250,9 @@ private:
 
 	FEdgeXDetector edgeDetector;
 
+	SceneHash sceneHashFunc;
+	real prevSceneHash = -1.0;
+
 #ifdef WITH_CXX_GUARDEDALLOC
 	MEM_CXX_CLASS_ALLOC_FUNCS("Freestyle:Controller")
 #endif
diff --git a/source/blender/freestyle/intern/blender_interface/FRS_freestyle.cpp b/source/blender/freestyle/intern/blender_interface/FRS_freestyle.cpp
index 32f49d48ee7..7443da77399 100644
--- a/source/blender/freestyle/intern/blender_interface/FRS_freestyle.cpp
+++ b/source/blender/freestyle/intern/blender_interface/FRS_freestyle.cpp
@@ -474,6 +474,9 @@ static void prepare(Main *bmain, Render *re, SceneRenderLayer *srl)
 		cout << "  Z = " << (z ? "enabled" : "disabled") << endl;
 	}
 
+	if (controller->hitViewMapCache())
+		return;
+
 	// compute view map
 	re->i.infostr = "Freestyle: View map creation";
 	re->stats_draw(re->sdh, &re->i);
@@ -589,6 +592,7 @@ Render *FRS_do_stroke_rendering(Render *re, SceneRenderLayer *srl, int render)
 
 	RenderMonitor monitor(re);
 	controller->setRenderMonitor(&monitor);
+	controller->setViewMapCache((srl->freestyleConfig.flags & FREESTYLE_VIEW_MAP_CACHE) ? true : false);
 
 	if (G.debug & G_DEBUG_FREESTYLE) {
 		cout << endl;
@@ -647,6 +651,17 @@ void FRS_finish_stroke_rendering(Render *re)
 	controller->Clear();
 }
 
+void FRS_free_view_map_cache()
+{
+	// free cache
+	controller->DeleteViewMap(true);
+#if 0
+	if (G.debug & G_DEBUG_FREESTYLE) {
+		printf("View map cache freed\n");
+	}
+#endif
+}
+
 //=======================================================
 //   Freestyle Panel Configuration
 //=======================================================
diff --git a/source/blender/freestyle/intern/scene_graph/SceneHash.cpp b/source/blender/freestyle/intern/scene_graph/SceneHash.cpp
new file mode 100644
index 00000000000..6e8856f1b93
--- /dev/null
+++ b/source/blender/freestyle/intern/scene_graph/SceneHash.cpp
@@ -0,0 +1,39 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+/** \file blender/freestyle/intern/scene_graph/SceneHash.cpp
+ *  \ingroup freestyle
+ */
+
+#include "SceneHash.h"
+
+namespace Freestyle {
+
+void SceneHash::visitIndexedFaceSet(IndexedFaceSet& ifs)
+{
+	const real *v = ifs.vertices();
+	const unsigned n = ifs.vsize();
+
+	for (unsigned i = 0; i < n; i++) {
+		_hashcode += v[i];
+	}
+}
+
+} /* namespace Freestyle */
diff --git a/source/blender/freestyle/intern/scene_graph/SceneHash.h b/source/blender/freestyle/intern/scene_graph/SceneHash.h
new file mode 100644
index 00000000000..8f5f847eaab
--- /dev/null
+++ b/source/blender/freestyle/intern/scene_graph/SceneHash.h
@@ -0,0 +1,67 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+#ifndef __FREESTYLE_SCENE_HASH_H__
+#define __FREESTYLE_SCENE_HASH_H__
+
+/** \file blender/freestyle/intern/scene_graph/SceneHash.h
+ *  \ingroup freestyle
+ */
+
+#include "IndexedFaceSet.h"
+#include "SceneVisitor.h"
+
+#ifdef WITH_CXX_GUARDEDALLOC
+#include "MEM_guardedalloc.h"
+#endif
+
+namespace Freestyle {
+
+class SceneHash : public SceneVisitor
+{
+public:
+	inline SceneHash() : SceneVisitor()
+	{
+		_hashcode = 0.0;
+	}
+
+	virtual ~SceneHash() {}
+
+	VISIT_DECL(IndexedFaceSet)
+
+	inline real getValue() {
+		return _hashcode;
+	}
+
+	inline void reset() {
+		_hashcode = 0.0;
+	}
+
+private:
+	real _hashcode;
+
+#ifdef WITH_CXX_GUARDEDALLOC
+	MEM_CXX_CLASS_ALLOC_FUNCS("Freestyle:SceneHash")
+#endif
+};
+
+} /* namespace Freestyle */
+
+#endif // __FREESTYLE_SCENE_HASH_H__
diff --git a/source/blender/makesdna/DNA_freestyle_types.h b/source/blender/makesdna/DNA_freestyle_types.h
index 195c7eb4841..d099511a088 100644
--- a/source/blender/makesdna/DNA_freestyle_types.h
+++ b/source/blender/makesdna/DNA_freestyle_types.h
@@ -50,6 +50,7 @@ struct Text;
 #define FREESTYLE_FACE_SMOOTHNESS_FLAG      (1 << 3)
 #define FREESTYLE_ADVANCED_OPTIONS_FLAG     (1 << 4)
 #define FREESTYLE_CULLING                   (1 << 5)
+#define FREESTYLE_VIEW_MAP_CACHE            (1 << 6)
 
 /* FreestyleConfig::mode */
 #define FREESTYLE_CONTROL_SCRIPT_MODE  1
diff --git a/source/blender/makesrna/intern/CMakeLists.txt b/source/blender/makesrna/intern/CMakeLists.txt
index 15f5253257a..d62a2e2c76e 100644
--- a/source/blender/makesrna/intern/CMakeLists.txt
+++ b/source/blender/makesrna/intern/CMakeLists.txt
@@ -265,6 +265,9 @@ if(WITH_BULLET)
 endif()
 
 if(WITH_FREESTYLE)
+	list(APPEND INC
+		../../freestyle
+	)
 	add_definitions(-DWITH_FREESTYLE)
 endif()
 
diff --git a/source/blender/makesrna/intern/SConscript b/source/blender/makesrna/intern/SConscript
index 08cbd6143a5..179a332336e 100644
--- a/source/blender/makesrna/intern/SConscript
+++ b/source/blender/makesrna/intern/SConscript
@@ -143,6 +143,7 @@ if env['WITH_BF_CYCLES']:
 
 if env['WITH_BF_FREESTYLE']:
     defs.append('WITH_FREESTYLE')
+    incs += ' ../../freestyle'
 
 if env['OURPLATFORM'] == 'linux':
     cflags='-pthread'
diff --git a/source/blender/makesrna/intern/rna_scene.c b/source/blender/makesrna/intern/rna_scene.c
index 97890997bbb..9af38ae2322 100644
--- a/source/blender/makesrna/intern/rna_scene.c
+++ b/source/blender/makesrna/intern/rna_scene.c
@@ -370,6 +370,10 @@ EnumPropertyItem bake_save_mode_items[] = {
 
 #include "RE_engine.h"
 
+#ifdef WITH_FREESTYLE
+#include "FRS_freestyle.h"
+#endif
+
 static void rna_SpaceImageEditor_uv_sculpt_update(Main *bmain, Scene *scene, PointerRNA *UNUSED(ptr))
 {
 	ED_space_image_uv_sculpt_update(bmain->wm.first, scene->toolsettings);
@@ -1179,6 +1183,13 @@ static void rna_Scene_freestyle_update(Main *UNUSED(bmain), Scene *UNUSED(scene)
 	DAG_id_tag_update(&scene->id, 0);
 }
 
+static void rna_Scene_use_view_map_cache_update(Main *UNUSED(bmain), Scene *UNUSED(scene), PointerRNA *ptr)
+{
+#ifdef WITH_FREESTYLE
+	FRS_free_view_map_cache();
+#endif
+}
+
 static void rna_SceneRenderLayer_name_set(PointerRNA *ptr, const char *value)
 {
 	Scene *scene = (Scene *)ptr->id.data;
@@ -3109,6 +3120,11 @@ static void rna_def_freestyle_settings(BlenderRNA *brna)
 	                         "Enable advanced edge detection options (sphere radius and Kr derivative epsilon)");
 	RNA_def_property_update(prop, NC_SCENE | ND_RENDER_OPTIONS, "rna_Scene_freestyle_update");
 
+	prop = RNA_def_property(srna, "use_view_map_cache", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_boolean_sdna(prop, NULL, "flags", FREESTYLE_VIEW_MAP_CACHE);
+	RNA_def_property_ui_text(prop, "View Map Cache", "Keep the computed view map and avoid re-calculating it if mesh geometry is unchanged");
+	RNA_def_property_update(prop, NC_SCENE | ND_RENDER_OPTIONS, "rna_Scene_use_view_map_cache_update");
+
 	prop = RNA_def_property(srna, "sphere_radius", PROP_FLOAT, PROP_NONE);
 	RNA_def_property_float_sdna(prop, NULL, "sphere_radius");
 	RNA_def_property_range(prop, 0.0, 1000.0);