From 07d7bc95e35bb90f9ef5b2db8b38c30749098918 Mon Sep 17 00:00:00 2001
From: Haroon Qureshi <haroonq@google.com>
Date: Thu, 26 Feb 2026 08:22:54 -0800
Subject: [PATCH] Expose vsm blur width parameter.

PiperOrigin-RevId: 875733943
Change-Id: Ic8cb423104d2e62ce295f6a2ab6fd67d548910a6
---
 src/experimental/filament/filament/light.cc      | 5 +++++
 src/experimental/filament/filament/light.h       | 2 ++
 src/experimental/filament/filament/scene_view.cc | 3 +++
 src/experimental/filament/filament/scene_view.h  | 1 +
 4 files changed, 11 insertions(+)

diff --git a/src/experimental/filament/filament/light.cc b/src/experimental/filament/filament/light.cc
index d26fd370..e0c090f7 100644
--- a/src/experimental/filament/filament/light.cc
+++ b/src/experimental/filament/filament/light.cc
@@ -72,6 +72,11 @@ Light::Light(ObjectManager* object_mgr, const Params& params)
       type == filament::LightManager::Type::DIRECTIONAL ? 4 : 1;
   opts.shadowBulbRadius = params.bulbradius;
   opts.mapSize = params.shadow_map_size;
+  if (params.vsm_blur_width > 0.0f) {
+    opts.vsm.elvsm = true;
+    opts.vsm.blurWidth = params.vsm_blur_width;
+  }
+
   builder.shadowOptions(opts);
 
   entity_ = utils::EntityManager::get().create();
diff --git a/src/experimental/filament/filament/light.h b/src/experimental/filament/filament/light.h
index 64dc0b8c..d32237eb 100644
--- a/src/experimental/filament/filament/light.h
+++ b/src/experimental/filament/filament/light.h
@@ -45,6 +45,8 @@ class Light {
     float bulbradius = 0.0f;
     // The size of the shadow map.
     int shadow_map_size = 2048;
+    // Blur width for EL VSM.
+    float vsm_blur_width = 0.0f;
     // Whether or not the light is a headlight.
     bool headlight = false;
   };
diff --git a/src/experimental/filament/filament/scene_view.cc b/src/experimental/filament/filament/scene_view.cc
index 3b25faaf..e30c342c 100644
--- a/src/experimental/filament/filament/scene_view.cc
+++ b/src/experimental/filament/filament/scene_view.cc
@@ -134,6 +134,8 @@ SceneView::SceneView(filament::Engine* engine, ObjectManager* object_mgr)
 
   default_shadow_map_size_ = ReadElement(
       m, "filament.shadows.map_size", default_shadow_map_size_);
+  default_vsm_blur_width_ = ReadElement(
+      m, "filament.shadows.vsm_blur_width", default_vsm_blur_width_);
 
   auto shadow_type = views_[kNormalIndex]->getShadowType();
   shadow_type = ReadElement(m, "filament.shadows.type", shadow_type);
@@ -298,6 +300,7 @@ void SceneView::PrepareLights() {
       params.range = model->light_range[i];
       params.intensity = model->light_intensity[i];
       params.shadow_map_size = default_shadow_map_size_;
+      params.vsm_blur_width = default_vsm_blur_width_;
       if (params.type == mjLIGHT_SPOT) {
         params.spot_cone_angle = model->light_cutoff[i];
       }
diff --git a/src/experimental/filament/filament/scene_view.h b/src/experimental/filament/filament/scene_view.h
index 94d1ac9a..4e746ce8 100644
--- a/src/experimental/filament/filament/scene_view.h
+++ b/src/experimental/filament/filament/scene_view.h
@@ -101,6 +101,7 @@ class SceneView {
   DrawMode active_mode_ = DrawMode::kNumDrawModes;
   float aspect_ratio_ = 1.0f;
   int default_shadow_map_size_ = 2048;
+  float default_vsm_blur_width_ = 0.0f;
   float fallback_head_light_intensity_ = 0.f;
   float fallback_scene_light_intensity_ = 80'000.f;
   float fallback_environment_light_intensity_ = 5'000.f;