Fix memory leak with Freestyle renders after recent changes

Render stored a shallow copy of the scene view layers and views for thread
safety, without proper functions to free it. But with the CoW depsgraph this
scene is already a copy of the original and an additional copy is not needed.

Refactor to use the scene view layers and some other settings directly instead
of making a copy.

7 files changed, 33 insertions, 79 deletions

diff --git a/source/blender/freestyle/intern/blender_interface/FRS_freestyle.cpp b/source/blender/freestyle/intern/blender_interface/FRS_freestyle.cpp
index 06365c3799f..af9ef7f352e 100644
--- a/source/blender/freestyle/intern/blender_interface/FRS_freestyle.cpp
+++ b/source/blender/freestyle/intern/blender_interface/FRS_freestyle.cpp
@@ -131,9 +131,9 @@ static void init_view(Render *re)
   int ymax = re->disprect.ymax;
 
   float thickness = 1.0f;
-  switch (re->r.line_thickness_mode) {
+  switch (re->scene->r.line_thickness_mode) {
     case R_LINE_THICKNESS_ABSOLUTE:
-      thickness = re->r.unit_line_thickness * (re->r.size / 100.0f);
+      thickness = re->scene->r.unit_line_thickness * (re->r.size / 100.0f);
       break;
     case R_LINE_THICKNESS_RELATIVE:
       thickness = height / 480.0f;
@@ -485,7 +485,7 @@ void FRS_composite_result(Render *re, ViewLayer *view_layer, Render *freestyle_r
     return;
   }
 
-  rl = render_get_active_layer(freestyle_render, freestyle_render->result);
+  rl = render_get_single_layer(freestyle_render, freestyle_render->result);
   if (!rl) {
     if (G.debug & G_DEBUG_FREESTYLE) {
       cout << "No source render layer to composite" << endl;
diff --git a/source/blender/render/intern/engine.cc b/source/blender/render/intern/engine.cc
index b8757d33580..acca657f7dc 100644
--- a/source/blender/render/intern/engine.cc
+++ b/source/blender/render/intern/engine.cc
@@ -1036,12 +1036,6 @@ bool RE_engine_render(Render *re, bool do_all)
     return true;
   }
 
-  /* update animation here so any render layer animation is applied before
-   * creating the render result */
-  if ((re->r.scemode & (R_NO_FRAME_UPDATE | R_BUTS_PREVIEW)) == 0) {
-    render_update_anim_renderdata(re, &re->scene->r, &re->scene->view_layers);
-  }
-
   /* Create engine. */
   RenderEngine *engine = re->engine;
 
diff --git a/source/blender/render/intern/pipeline.cc b/source/blender/render/intern/pipeline.cc
index d2929a7f6ea..e71ad1e26c1 100644
--- a/source/blender/render/intern/pipeline.cc
+++ b/source/blender/render/intern/pipeline.cc
@@ -261,13 +261,10 @@ RenderResult *RE_MultilayerConvert(
   return render_result_new_from_exr(exrhandle, colorspace, predivide, rectx, recty);
 }
 
-RenderLayer *render_get_active_layer(Render *re, RenderResult *rr)
+RenderLayer *render_get_single_layer(Render *re, RenderResult *rr)
 {
-  ViewLayer *view_layer = static_cast<ViewLayer *>(
-      BLI_findlink(&re->view_layers, re->active_view_layer));
-
-  if (view_layer) {
-    RenderLayer *rl = RE_GetRenderLayer(rr, view_layer->name);
+  if (re->single_view_layer[0]) {
+    RenderLayer *rl = RE_GetRenderLayer(rr, re->single_view_layer);
 
     if (rl) {
       return rl;
@@ -385,8 +382,8 @@ void RE_AcquireResultImageViews(Render *re, RenderResult *rr)
       RenderView *rv = static_cast<RenderView *>(rr->views.first);
       rr->have_combined = (rv->rectf != nullptr);
 
-      /* active layer */
-      RenderLayer *rl = render_get_active_layer(re, re->result);
+      /* single layer */
+      RenderLayer *rl = render_get_single_layer(re, re->result);
 
       if (rl) {
         if (rv->rectf == nullptr) {
@@ -443,7 +440,7 @@ void RE_AcquireResultImage(Render *re, RenderResult *rr, const int view_id)
       rr->rect32 = rv->rect32;
 
       /* active layer */
-      rl = render_get_active_layer(re, re->result);
+      rl = render_get_single_layer(re, re->result);
 
       if (rl) {
         if (rv->rectf == nullptr) {
@@ -583,9 +580,6 @@ void RE_FreeRender(Render *re)
   BLI_mutex_end(&re->engine_draw_mutex);
   BLI_mutex_end(&re->highlighted_tiles_mutex);
 
-  BLI_freelistN(&re->view_layers);
-  BLI_freelistN(&re->r.views);
-
   BKE_curvemapping_free_data(&re->r.mblur_shutter_curve);
 
   if (re->highlighted_tiles != nullptr) {
@@ -705,12 +699,11 @@ static void re_init_resolution(Render *re, Render *source, int winx, int winy, r
 
 void render_copy_renderdata(RenderData *to, RenderData *from)
 {
-  BLI_freelistN(&to->views);
+  /* Mostly shallow copy referencing pointers in scene renderdata. */
   BKE_curvemapping_free_data(&to->mblur_shutter_curve);
 
   memcpy(to, from, sizeof(*to));
 
-  BLI_duplicatelist(&to->views, &from->views);
   BKE_curvemapping_copy_data(&to->mblur_shutter_curve, &from->mblur_shutter_curve);
 }
 
@@ -731,9 +724,7 @@ void RE_InitState(Render *re,
 
   /* copy render data and render layers for thread safety */
   render_copy_renderdata(&re->r, rd);
-  BLI_freelistN(&re->view_layers);
-  BLI_duplicatelist(&re->view_layers, render_layers);
-  re->active_view_layer = 0;
+  re->single_view_layer[0] = '\0';
 
   if (source) {
     /* reuse border flags from source renderer */
@@ -762,11 +753,8 @@ void RE_InitState(Render *re,
   }
 
   if (single_layer) {
-    int index = BLI_findindex(render_layers, single_layer);
-    if (index != -1) {
-      re->active_view_layer = index;
-      re->r.scemode |= R_SINGLE_LAYER;
-    }
+    STRNCPY(re->single_view_layer, single_layer->name);
+    re->r.scemode |= R_SINGLE_LAYER;
   }
 
   /* if preview render, we try to keep old result */
@@ -779,13 +767,16 @@ void RE_InitState(Render *re,
       re->result = nullptr;
     }
     else if (re->result) {
-      ViewLayer *active_render_layer = static_cast<ViewLayer *>(
-          BLI_findlink(&re->view_layers, re->active_view_layer));
       bool have_layer = false;
 
-      LISTBASE_FOREACH (RenderLayer *, rl, &re->result->layers) {
-        if (STREQ(rl->name, active_render_layer->name)) {
-          have_layer = true;
+      if (re->single_view_layer[0] == '\0' && re->result->layers.first) {
+        have_layer = true;
+      }
+      else {
+        LISTBASE_FOREACH (RenderLayer *, rl, &re->result->layers) {
+          if (STREQ(rl->name, re->single_view_layer)) {
+            have_layer = true;
+          }
         }
       }
 
@@ -817,27 +808,6 @@ void RE_InitState(Render *re,
   RE_point_density_fix_linking();
 }
 
-void render_update_anim_renderdata(Render *re, RenderData *rd, ListBase *render_layers)
-{
-  /* filter */
-  re->r.gauss = rd->gauss;
-
-  /* motion blur */
-  re->r.blurfac = rd->blurfac;
-
-  /* freestyle */
-  re->r.line_thickness_mode = rd->line_thickness_mode;
-  re->r.unit_line_thickness = rd->unit_line_thickness;
-
-  /* render layers */
-  BLI_freelistN(&re->view_layers);
-  BLI_duplicatelist(&re->view_layers, render_layers);
-
-  /* render views */
-  BLI_freelistN(&re->r.views);
-  BLI_duplicatelist(&re->r.views, &rd->views);
-}
-
 void RE_display_init_cb(Render *re, void *handle, void (*f)(void *handle, RenderResult *rr))
 {
   re->display_init = f;
@@ -979,7 +949,7 @@ static void render_result_uncrop(Render *re)
       re->result = rres;
 
       /* Weak, the display callback wants an active render-layer pointer. */
-      re->result->renlay = render_get_active_layer(re, re->result);
+      re->result->renlay = render_get_single_layer(re, re->result);
 
       BLI_rw_mutex_unlock(&re->resultmutex);
 
@@ -1217,7 +1187,7 @@ static void do_render_compositor(Render *re)
 
   /* Weak: the display callback wants an active render-layer pointer. */
   if (re->result != nullptr) {
-    re->result->renlay = render_get_active_layer(re, re->result);
+    re->result->renlay = render_get_single_layer(re, re->result);
     re->display_update(re->duh, re->result, nullptr);
   }
 }
@@ -1676,7 +1646,6 @@ static int render_init_from_main(Render *re,
 
   /* not too nice, but it survives anim-border render */
   if (anim) {
-    render_update_anim_renderdata(re, &scene->r, &scene->view_layers);
     re->disprect = disprect;
     return 1;
   }
@@ -1890,12 +1859,10 @@ void RE_RenderFreestyleExternal(Render *re)
   LISTBASE_FOREACH (RenderView *, rv, &re->result->views) {
     RE_SetActiveRenderView(re, rv->name);
 
-    ViewLayer *active_view_layer = static_cast<ViewLayer *>(
-        BLI_findlink(&re->view_layers, re->active_view_layer));
     FRS_begin_stroke_rendering(re);
 
-    LISTBASE_FOREACH (ViewLayer *, view_layer, &re->view_layers) {
-      if ((re->r.scemode & R_SINGLE_LAYER) && view_layer != active_view_layer) {
+    LISTBASE_FOREACH (ViewLayer *, view_layer, &re->scene->view_layers) {
+      if ((re->r.scemode & R_SINGLE_LAYER) && !STREQ(view_layer->name, re->single_view_layer)) {
         continue;
       }
 
diff --git a/source/blender/render/intern/pipeline.h b/source/blender/render/intern/pipeline.h
index 689e4509da3..e5da3cb8830 100644
--- a/source/blender/render/intern/pipeline.h
+++ b/source/blender/render/intern/pipeline.h
@@ -17,14 +17,7 @@ struct RenderResult;
 extern "C" {
 #endif
 
-struct RenderLayer *render_get_active_layer(struct Render *re, struct RenderResult *rr);
-/**
- * Update some variables that can be animated, and otherwise wouldn't be due to
- * #RenderData getting copied once at the start of animation render.
- */
-void render_update_anim_renderdata(struct Render *re,
-                                   struct RenderData *rd,
-                                   struct ListBase *render_layers);
+struct RenderLayer *render_get_single_layer(struct Render *re, struct RenderResult *rr);
 void render_copy_renderdata(struct RenderData *to, struct RenderData *from);
 
 #ifdef __cplusplus
diff --git a/source/blender/render/intern/render_result.cc b/source/blender/render/intern/render_result.cc
index 94f6e2f1509..1cd95831ddf 100644
--- a/source/blender/render/intern/render_result.cc
+++ b/source/blender/render/intern/render_result.cc
@@ -321,7 +321,7 @@ RenderResult *render_result_new(Render *re,
     rl->layflag = SCE_LAY_FLAG_DEFAULT;
     rl->passflag = SCE_PASS_COMBINED;
 
-    re->active_view_layer = 0;
+    re->single_view_layer[0] = '\0';
   }
 
   /* Border render; calculate offset for use in compositor. compo is centralized coords. */
@@ -768,8 +768,8 @@ void render_result_single_layer_end(Render *re)
 
     /* reconstruct render result layers */
     int nr = 0;
-    LISTBASE_FOREACH (ViewLayer *, view_layer, &re->view_layers) {
-      if (nr == re->active_view_layer) {
+    LISTBASE_FOREACH (ViewLayer *, view_layer, &re->scene->view_layers) {
+      if (STREQ(view_layer->name, re->single_view_layer)) {
         BLI_addtail(&re->result->layers, rl);
       }
       else {
diff --git a/source/blender/render/intern/render_result.h b/source/blender/render/intern/render_result.h
index 2e76efba8a3..6e971d45d31 100644
--- a/source/blender/render/intern/render_result.h
+++ b/source/blender/render/intern/render_result.h
@@ -136,10 +136,11 @@ void render_result_views_shallowdelete(struct RenderResult *rr);
   { \
     int nr_; \
     ViewLayer *iter_; \
-    for (nr_ = 0, iter_ = static_cast<ViewLayer *>((re_)->view_layers.first); iter_ != NULL; \
+    for (nr_ = 0, iter_ = static_cast<ViewLayer *>((re_)->scene->view_layers.first); \
+         iter_ != NULL; \
          iter_ = iter_->next, nr_++) { \
       if (!G.background && (re_)->r.scemode & R_SINGLE_LAYER) { \
-        if (nr_ != re->active_view_layer) { \
+        if (!STREQ(iter_->name, re->single_view_layer)) { \
           continue; \
         } \
       } \
diff --git a/source/blender/render/intern/render_types.h b/source/blender/render/intern/render_types.h
index 29bac6e2766..ad58f081388 100644
--- a/source/blender/render/intern/render_types.h
+++ b/source/blender/render/intern/render_types.h
@@ -76,8 +76,7 @@ struct Render {
   struct Main *main;
   Scene *scene;
   RenderData r;
-  ListBase view_layers;
-  int active_view_layer;
+  char single_view_layer[MAX_NAME];
   struct Object *camera_override;
 
   ThreadMutex highlighted_tiles_mutex;