diff --git a/CMakeLists.txt b/CMakeLists.txt
index 020bf4c..622e443 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.1)
+cmake_minimum_required(VERSION 3.12)
 project(MiyukiRenderer)
 
 
@@ -66,21 +66,22 @@ file(GLOB libcoreSource src/core/*.cpp
 
 
 IF(USE_EMBREE)
-    add_compile_definitions(MYK_USE_EMBREE)
     IF(EMBREE_FROM_SOURCE)
         include(ExternalProject)
         include(${PROJECT_SOURCE_DIR}/cmake/cmake-embree)
 		include_directories(${EMBREE_INCLUDE_DIRS})
+        add_compile_definitions(MYK_USE_EMBREE)
     ELSE()
         IF(WIN32)
             set(CMAKE_PREFIX_PATH ${CMAKE_PREFIX_PATH} "C:/Program Files/Intel/Embree3 x64")
         ENDIF()
-        find_package(embree 3.6 REQUIRED)
+        find_package(embree 3.6)
         IF(NOT embree_FOUND)
-            message(FATAL_ERROR "Embree 3.6 not found")
+            message("Embree 3.6 not found; Falling back to custom BVH backend")
+        ELSE()
+            add_compile_definitions(MYK_USE_EMBREE)
+            include_directories(${EMBREE_INCLUDE_DIRS})
         ENDIF()
-        include_directories(${EMBREE_INCLUDE_DIRS})
-
     ENDIF()
 ENDIF()
 
diff --git a/data/living_room/image.png b/data/living_room/image.png
index 0a4b2c9..eb31b9b 100644
Binary files a/data/living_room/image.png and b/data/living_room/image.png differ
diff --git a/data/living_room/scene.json b/data/living_room/scene.json
index 1033ffc..a150f20 100644
--- a/data/living_room/scene.json
+++ b/data/living_room/scene.json
@@ -28,7 +28,7 @@
   "integrator": {
     "type": "PathTracer",
     "props": {
-      "spp": 1024,
+      "spp": 8,
       "minDepth": 3,
       "maxDepth": 5
     }
@@ -51,7 +51,7 @@
                     "props": {
                       "color": {
                         "props": {
-                          "imagePath": "textures\\apple.jpg"
+                          "imagePath": "./textures/apple.jpg"
                         },
                         "type": "ImageTextureShader"
                       }
@@ -392,7 +392,7 @@
                     "props": {
                       "color": {
                         "props": {
-                          "imagePath": "textures\\book-spines.jpg"
+                          "imagePath": "./textures/book-spines.jpg"
                         },
                         "type": "ImageTextureShader"
                       }
@@ -526,7 +526,7 @@
                     "props": {
                       "color": {
                         "props": {
-                          "imagePath": "textures\\carpet-text3b.jpg"
+                          "imagePath": "./textures/carpet-text3b.jpg"
                         },
                         "type": "ImageTextureShader"
                       }
@@ -591,7 +591,7 @@
                     "props": {
                       "color": {
                         "props": {
-                          "imagePath": "textures\\Shade-paper.jpg"
+                          "imagePath": "./textures/Shade-paper.jpg"
                         },
                         "type": "ImageTextureShader"
                       }
@@ -725,7 +725,7 @@
                     "props": {
                       "color": {
                         "props": {
-                          "imagePath": "textures\\cushion-green-circles.jpg"
+                          "imagePath": "./textures/cushion-green-circles.jpg"
                         },
                         "type": "ImageTextureShader"
                       }
@@ -790,7 +790,7 @@
                     "props": {
                       "color": {
                         "props": {
-                          "imagePath": "textures\\cushion-stripe-purple.jpg"
+                          "imagePath": "./textures/cushion-stripe-purple.jpg"
                         },
                         "type": "ImageTextureShader"
                       }
@@ -855,7 +855,7 @@
                     "props": {
                       "color": {
                         "props": {
-                          "imagePath": "textures\\cushion-purple-yellow-stripe.jpg"
+                          "imagePath": "./textures/cushion-purple-yellow-stripe.jpg"
                         },
                         "type": "ImageTextureShader"
                       }
@@ -1060,7 +1060,7 @@
                         "props": {
                           "expr": [
                             "image",
-                            "textures\\wood4.jpg"
+                            "./textures/wood4.jpg"
                           ]
                         },
                         "type": "ExprShader"
@@ -1195,7 +1195,7 @@
                     "props": {
                       "color": {
                         "props": {
-                          "imagePath": "textures\\shade-stripes.jpg"
+                          "imagePath": "./textures/shade-stripes.jpg"
                         },
                         "type": "ImageTextureShader"
                       }
@@ -1260,7 +1260,7 @@
                     "props": {
                       "color": {
                         "props": {
-                          "imagePath": "textures\\pic5wide.jpg"
+                          "imagePath": "./textures/pic5wide.jpg"
                         },
                         "type": "ImageTextureShader"
                       }
@@ -1463,7 +1463,7 @@
                     "props": {
                       "color": {
                         "props": {
-                          "imagePath": "textures\\magazine.jpg"
+                          "imagePath": "./textures/magazine.jpg"
                         },
                         "type": "ImageTextureShader"
                       }
@@ -1597,7 +1597,7 @@
                     "props": {
                       "color": {
                         "props": {
-                          "imagePath": "textures\\picture11-vert.jpg"
+                          "imagePath": "./textures/picture11-vert.jpg"
                         },
                         "type": "ImageTextureShader"
                       }
@@ -1662,7 +1662,7 @@
                     "props": {
                       "color": {
                         "props": {
-                          "imagePath": "textures\\photo1.jpg"
+                          "imagePath": "./textures/photo1.jpg"
                         },
                         "type": "ImageTextureShader"
                       }
@@ -1727,7 +1727,7 @@
                     "props": {
                       "color": {
                         "props": {
-                          "imagePath": "textures\\photo3.jpg"
+                          "imagePath": "./textures/photo3.jpg"
                         },
                         "type": "ImageTextureShader"
                       }
@@ -1792,7 +1792,7 @@
                     "props": {
                       "color": {
                         "props": {
-                          "imagePath": "textures\\photo2.jpg"
+                          "imagePath": "./textures/photo2.jpg"
                         },
                         "type": "ImageTextureShader"
                       }
@@ -1857,7 +1857,7 @@
                     "props": {
                       "color": {
                         "props": {
-                          "imagePath": "textures\\photo4.jpg"
+                          "imagePath": "./textures/photo4.jpg"
                         },
                         "type": "ImageTextureShader"
                       }
diff --git a/src/core/accelerators/embree-backend.cpp b/src/core/accelerators/embree-backend.cpp
index 89bacdd..7ca002e 100644
--- a/src/core/accelerators/embree-backend.cpp
+++ b/src/core/accelerators/embree-backend.cpp
@@ -24,12 +24,17 @@
 #include <miyuki.foundation/log.hpp>
 #include <miyuki.renderer/ray.h>
 #include <miyuki.renderer/scene.h>
-#include <embree3/rtcore.h>
 
 #ifdef MYK_USE_EMBREE
+#include <embree3/rtcore.h>
+#endif
+
+
+
 
 #define QUERY_PROP(prop) log::log("{}: {}\n", #prop, rtcGetDeviceProperty(device, prop) ? true : false)
 namespace miyuki::core {
+#ifdef MYK_USE_EMBREE
     class EmbreeAccelerator::Impl {
         RTCDevice device;
         RTCScene rtcScene = nullptr;
@@ -135,12 +140,16 @@ namespace miyuki::core {
     }
 
 #else
+    EmbreeAccelerator::EmbreeAccelerator(){}
+    EmbreeAccelerator::~EmbreeAccelerator() {}
+    bool EmbreeAccelerator::occlude(const struct miyuki::core::Ray &ray) {
+        MIYUKI_NOT_IMPLEMENTED();
+    }
     void miyuki::core::EmbreeAccelerator::build(miyuki::core::Scene &scene) { MIYUKI_NOT_IMPLEMENTED(); }
 
     bool miyuki::core::EmbreeAccelerator::intersect(const miyuki::core::Ray &ray, miyuki::core::Intersection &isct) {
         MIYUKI_NOT_IMPLEMENTED();
+        return false;
     }
-    return false;
-
 #endif
 }
\ No newline at end of file
diff --git a/src/core/accelerators/embree-backend.h b/src/core/accelerators/embree-backend.h
index 7956085..eaf2dee 100644
--- a/src/core/accelerators/embree-backend.h
+++ b/src/core/accelerators/embree-backend.h
@@ -28,7 +28,8 @@
 #include <miyuki.foundation/noncopyable.hpp>
 #include <miyuki.renderer/ray.h>
 
-namespace miyuki::core {
+namespace miyuki::core{
+
     class EmbreeAccelerator final : public Accelerator, private NonCopyable{
         class Impl;
         Impl *impl = nullptr;
@@ -42,9 +43,9 @@ namespace miyuki::core {
 
         bool occlude(const Ray & ray)override;
 
-        bool4 intersect4(const Ray4 &ray, Intersection4 &isct) override;
+        bool4 intersect4(const Ray4 &ray, Intersection4 &isct) override{}
 
-        bool8 intersect8(const Ray8 &ray, Intersection8 &isct) override;
+        bool8 intersect8(const Ray8 &ray, Intersection8 &isct) override{}
 
         ~EmbreeAccelerator();