Implemented shadow_task within light_tasks_delegate.

Added shadow_task to final and viewport engines.
Added use_storm_shadows to struct ShadingSettings.

@@ -44,6 +44,7 @@ class HydraSceneDelegate : public pxr::HdSceneDelegate {
     std::string studiolight_name;
     float studiolight_rotation;
     float studiolight_intensity;
+    bool use_storm_shadows = false;

@@ -95,0 +100,4 @@
+  bool use_shadow = (light->mode & LA_SHADOW) && light->type == LA_SUN;
+  scene_delegate_->shading_settings.use_storm_shadows |= use_shadow;
+  if (use_shadow) {
+    data_[pxr::HdLightTokens->hasShadow] = use_shadow;

@@ -95,0 +101,4 @@
+  scene_delegate_->shading_settings.use_storm_shadows |= use_shadow;
+  if (use_shadow) {
+    data_[pxr::HdLightTokens->hasShadow] = use_shadow;
+    pxr::HdxShadowParams shadowParams_ = pxr::HdxShadowParams();

@@ -95,0 +123,4 @@
+    data_[pxr::HdLightTokens->shadowParams] = shadowParams_;
+    data_[pxr::HdLightTokens->shadowCollection] = pxr::HdRprimCollection(
+        pxr::HdTokens->geometry, pxr::HdReprSelector(pxr::HdReprTokens->refined));
+  }

@@ -0,0 +5,4 @@
+
+namespace blender::io::hydra {
+
+class ShadowMatrix : public pxr::HdxShadowMatrixComputation {

@@ -0,0 +19,4 @@
+    return {_shadowMatrix};
+  }
+
+  std::vector<pxr::GfMatrix4d> Compute(const pxr::CameraUtilFraming &framing,

@@ -0,0 +25,4 @@
+    return {_shadowMatrix};
+  }
+
+  void SetNearFar(const float &near_dist, const float &far_dist)

@@ -0,0 +35,4 @@
+    _frustum.Transform(transform);
+  }
+
+  void SetWindow(const double &x, const double &y)

@@ -0,0 +42,4 @@
+
+  void CalculateMatrix()
+  {
+    _shadowMatrix = _frustum.ComputeViewMatrix() * _frustum.ComputeProjectionMatrix();