Handle shadow receivers w/ VSM more robustly

VSM requires shadow receivers to be in the shadowmap, instead of
handling this in the shadow mapping code, we're handling it in 
FScene::prepare(), which guarantees it'll ripple everywhere it needs to.

filament/src/Scene.cpp

@@ -47,7 +47,7 @@ FScene::FScene(FEngine& engine) :
 FScene::~FScene() noexcept = default;
 
 
-void FScene::prepare(const mat4f& worldOriginTransform) {
+void FScene::prepare(const mat4f& worldOriginTransform, bool shadowReceiversAreCasters) noexcept {
     // TODO: can we skip this in most cases? Since we rely on indices staying the same,
     //       we could only skip, if nothing changed in the RCM.
 
@@ -119,12 +119,17 @@ void FScene::prepare(const mat4f& worldOriginTransform) {
             // compute the world AABB so we can perform culling
             const Box worldAABB = rigidTransform(rcm.getAABB(ri), worldTransform);
 
+            auto visibility = rcm.getVisibility(ri);
+            if (shadowReceiversAreCasters && visibility.receiveShadows) {
+                visibility.castShadows = true;
+            }
+
             // we know there is enough space in the array
             sceneData.push_back_unsafe(
                     ri,                       // RENDERABLE_INSTANCE
                     worldTransform,           // WORLD_TRANSFORM
                     reversedWindingOrder,     // REVERSED_WINDING_ORDER
-                    rcm.getVisibility(ri),    // VISIBILITY_STATE
+                    visibility,               // VISIBILITY_STATE
                     rcm.getBonesUbh(ri),      // BONES_UBH
                     worldAABB.center,         // WORLD_AABB_CENTER
                     0,                        // VISIBLE_MASK

filament/src/View.cpp

@@ -414,7 +414,7 @@ void FView::prepare(FEngine& engine, backend::DriverApi& driver, ArenaScope& are
      * Gather all information needed to render this scene. Apply the world origin to all
      * objects in the scene.
      */
-    scene->prepare(worldOriginScene);
+    scene->prepare(worldOriginScene, hasVsm());
 
     /*
      * Light culling: runs in parallel with Renderable culling (below)
@@ -594,20 +594,17 @@ void FView::computeVisibilityMasks(
         //
         // It is written without if statements to avoid branches, which allows it to be vectorized 16x.
 
-        const bool visRenderables   = (!v.culling || (mask & VISIBLE_RENDERABLE))    && inVisibleLayer;
-        const bool vvsmRenderShadow = hasVsm && v.receiveShadows;
-        const bool visShadowParticipant = v.castShadows || vvsmRenderShadow;
-        const bool visShadowRenderable =
-            (!v.culling || (mask & VISIBLE_DIR_SHADOW_RENDERABLE)) && inVisibleLayer && visShadowParticipant;
+        const bool visRenderables = (!v.culling || (mask & VISIBLE_RENDERABLE)) && inVisibleLayer;
+        const bool visShadowParticipant = v.castShadows;
+        const bool visShadowRenderable = (!v.culling || (mask & VISIBLE_DIR_SHADOW_RENDERABLE))
+                && inVisibleLayer && visShadowParticipant;
         visibleMask[i] = Culler::result_type(visRenderables) |
                 Culler::result_type(visShadowRenderable << 1u);
         // this loop gets fully unrolled
         for (size_t j = 0; j < CONFIG_MAX_SHADOW_CASTING_SPOTS; ++j) {
-            const bool vvsmSpotRenderShadow = hasVsm && v.receiveShadows;
-            const bool visSpotShadowParticipant = v.castShadows || vvsmSpotRenderShadow;
             const bool visSpotShadowRenderable =
-                (!v.culling || (mask & VISIBLE_SPOT_SHADOW_RENDERABLE_N(j))) &&
-                        inVisibleLayer && visSpotShadowParticipant;
+                    (!v.culling || (mask & VISIBLE_SPOT_SHADOW_RENDERABLE_N(j))) &&
+                        inVisibleLayer && visShadowParticipant;
             visibleMask[i] |=
                 Culler::result_type(visSpotShadowRenderable << VISIBLE_SPOT_SHADOW_RENDERABLE_N_BIT(j));
         }

filament/src/details/Scene.h

@@ -84,8 +84,9 @@ public:
     ~FScene() noexcept;
     void terminate(FEngine& engine);
 
-    void prepare(const math::mat4f& worldOriginTransform);
-    void prepareDynamicLights(const CameraInfo& camera, ArenaScope& arena, backend::Handle<backend::HwUniformBuffer> lightUbh) noexcept;
+    void prepare(const math::mat4f& worldOriginTransform, bool shadowReceiversAreCasters) noexcept;
+    void prepareDynamicLights(const CameraInfo& camera, ArenaScope& arena,
+            backend::Handle<backend::HwUniformBuffer> lightUbh) noexcept;
 
 
     filament::backend::Handle<backend::HwUniformBuffer> getRenderableUBO() const noexcept {