CIS5650-Fall-2024 · hazard-10 · Sep 29, 2024 · Sep 30, 2024 · Sep 30, 2024 · Sep 30, 2024
diff --git a/.gitignore b/.gitignore
@@ -23,7 +23,7 @@ build
 .LSOverride
 
 # Icon must end with two \r
-Icon
+Icon
 
 # Thumbnails
 ._*
@@ -189,7 +189,6 @@ install_manifest.txt
 *.slo
 *.lo
 *.o
-*.obj
 
 # Precompiled Headers
 *.gch
@@ -276,7 +275,6 @@ artifacts/
 *_i.h
 *.ilk
 *.meta
-*.obj
 *.pch
 *.pdb
 *.pgc

diff --git a/.vscode/settings.json b/.vscode/settings.json
@@ -0,0 +1,83 @@
+{
+    "files.associations": {
+        "cstdlib": "cpp",
+        "filesystem": "cpp",
+        "vector": "cpp",
+        "xstring": "cpp",
+        "iostream": "cpp",
+        "algorithm": "cpp",
+        "any": "cpp",
+        "array": "cpp",
+        "atomic": "cpp",
+        "bit": "cpp",
+        "cctype": "cpp",
+        "charconv": "cpp",
+        "chrono": "cpp",
+        "clocale": "cpp",
+        "cmath": "cpp",
+        "codecvt": "cpp",
+        "compare": "cpp",
+        "concepts": "cpp",
+        "condition_variable": "cpp",
+        "cstdarg": "cpp",
+        "cstddef": "cpp",
+        "cstdint": "cpp",
+        "cstdio": "cpp",
+        "cstring": "cpp",
+        "ctime": "cpp",
+        "cwchar": "cpp",
+        "exception": "cpp",
+        "format": "cpp",
+        "forward_list": "cpp",
+        "fstream": "cpp",
+        "functional": "cpp",
+        "initializer_list": "cpp",
+        "iomanip": "cpp",
+        "ios": "cpp",
+        "iosfwd": "cpp",
+        "istream": "cpp",
+        "iterator": "cpp",
+        "limits": "cpp",
+        "list": "cpp",
+        "locale": "cpp",
+        "map": "cpp",
+        "memory": "cpp",
+        "mutex": "cpp",
+        "new": "cpp",
+        "numeric": "cpp",
+        "optional": "cpp",
+        "ostream": "cpp",
+        "ranges": "cpp",
+        "ratio": "cpp",
+        "regex": "cpp",
+        "set": "cpp",
+        "span": "cpp",
+        "sstream": "cpp",
+        "stdexcept": "cpp",
+        "stop_token": "cpp",
+        "streambuf": "cpp",
+        "string": "cpp",
+        "system_error": "cpp",
+        "thread": "cpp",
+        "tuple": "cpp",
+        "type_traits": "cpp",
+        "typeinfo": "cpp",
+        "unordered_map": "cpp",
+        "utility": "cpp",
+        "valarray": "cpp",
+        "xfacet": "cpp",
+        "xhash": "cpp",
+        "xiosbase": "cpp",
+        "xlocale": "cpp",
+        "xlocbuf": "cpp",
+        "xlocinfo": "cpp",
+        "xlocmes": "cpp",
+        "xlocmon": "cpp",
+        "xlocnum": "cpp",
+        "xloctime": "cpp",
+        "xmemory": "cpp",
+        "xtr1common": "cpp",
+        "xtree": "cpp",
+        "xutility": "cpp"
+    }
+}
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -61,6 +61,8 @@ set(headers
     src/sceneStructs.h
     src/preview.h
     src/utilities.h
+    src/tiny_obj_loader.h
+    src/bvh.h
 )
 
 set(sources
@@ -74,6 +76,8 @@ set(sources
     src/scene.cpp
     src/preview.cpp
     src/utilities.cpp
+    src/tiny_obj_loader.cc
+    src/bvh.cpp
 )
 
 set(imgui_headers

diff --git a/README.md b/README.md
@@ -1,13 +1,198 @@
+![Cover](img/UI.png)
+
 CUDA Path Tracer
 ================
 
 **University of Pennsylvania, CIS 565: GPU Programming and Architecture, Project 3**
 
-* (TODO) YOUR NAME HERE
-* Tested on: (TODO) Windows 22, i7-2222 @ 2.22GHz 22GB, GTX 222 222MB (Moore 2222 Lab)
+* Jiahang Mao
+  * [LinkedIn](https://www.linkedin.com/in/jay-jiahang-m-b05608192/)
+* Tested on: Windows 11, i5-13600kf @ 5.0GHz 64GB, RTX 4090 24GB, Personal Computer
+
+## 1. Key feature implemented
+
+Part 1
+1. Cuda path tracing with lambertian and specular shading kernel
+2. Unhit path termination using Stream Compaction
+3. Sort ray-scene intersection by material type
+4. Stochastic sampled antialiasing
+
+Part 2
+1. Obj mesh import.
+2. BVH. Tree construction done on CPU, traversal with GPU. Configurable with either max depth or max leaf size.
+3. Refraction. Support transmissive-only and glass-like material.
+
+## 2. Build 
+
+Use C++ 17 or later instead of default C++ 14 with VS2022. Reason is because I added `<filesystem.h>` to support importing files using windows file system.
+
+Change under property -> C/C++ -> Language -> C++ Language Standard
+
+![How to](img/clang_update.png)
+
+
+## 3. Navigating UI
+
+I made some updates to the UI, building on top of the imgui.
+
+![UI](img/UI.png)
+
+#### Mesh Options
+* `Centralize mesh` When loading loading arbitrary obj mesh, this option automatically compute the center and scale, then apply a transformation to the center of camera's front pov.
+* `Mesh transformation` Post-import transformation also customizable.
+#### Acceleration Structure
+A single choice between three options
+* `None` No accleration structure will be applied. For each render pass the intersection checks each ray against all geometry in the scene.
+* `Basic Bounding Volume Culling` Conceptually equivalent to a depth-equals-to-one BVH. Construct a single bounding box surrounding the mesh. 
+* `Bounding Volume Hierarchy` Construct a tree-like structure to organize the geometry. The tree is built on CPU and traversed on GPU.
+  ![UI](img/bvh_ui.png)
+  * `Bins to Split Per Axis` Controls the number of bins used when determining the best split plane during BVH construction.
+  * `BVH Constraint` Choose between using a maximum leaf size or maximum depth as the stopping criterion for BVH construction.
+    * `Max Leaf Size` The maximum number of primitives allowed in a leaf node.
+    * `Max Depth` The maximum depth allowed for the BVH tree.
+#### Render Options
+* `Use Path Tracing` Toggle between path tracing and basic shading. Latter suited for quick view of geometry.
+* `Sort by Material` Enable/disable sorting of ray-scene intersections by material type.
+#### Loading file
+* Support either .json or .obj file. When importing an obj file, automatically load a display room scene under ./scenes/display_room.json
+
+    ![UI](img/file_UI.png)
+#### Program output
+* Command prompt will have useful info about the mesh and bvh for debugging.
+    ```console
+    --- Mesh Info ---
+    Loaded 5664 vertices, 11272 faces, and 1 face materials.
+    Auto-centering object...
+    Geometric Center: vec3(0.108734, 0.431662, 0.382079)
+    Average Distance to center : 1.03667
+    --- BVH Info ---
+    Building BVH...
+    Validating BVH...
+    BVH is valid. Max depth: 50, largest leaf size: 69
+    ```
+## 4. Performance benchmark
+
+#### 4.1 Stream Compaction, on open and close scene
+
+
+A sample output of number of rays after stream compaction after each iteration. Tested on scenes/cornell_refraction.json
+
+Results 1:
+Tested with cornell_refraction.json there are a total of 7 materials and 9 geometries, all of them are either box or spheres.
+
+  ![SC1](img/sc_bar.png)
+  ```
+  num_paths: 588297 at depth 1 of iter18
+  num_paths: 481950 at depth 2 of iter18
+  num_paths: 398397 at depth 3 of iter18
+  num_paths: 326704 at depth 4 of iter18
+  num_paths: 266102 at depth 5 of iter18
+  num_paths: 217403 at depth 6 of iter18
+  num_paths: 178307 at depth 7 of iter18
+  num_paths: 0 at depth 8 of iter18
+  num_paths: 588302 at depth 1 of iter19
+  num_paths: 482180 at depth 2 of iter19
+  num_paths: 397826 at depth 3 of iter19
+  num_paths: 326109 at depth 4 of iter19
+  num_paths: 265074 at depth 5 of iter19
+  num_paths: 216725 at depth 6 of iter19
+  num_paths: 177920 at depth 7 of iter19
+  num_paths: 0 at depth 8 of iter19
+  num_paths: 588302 at depth 1 of iter20
+  num_paths: 482791 at depth 2 of iter20
+  num_paths: 398975 at depth 3 of iter20
+  num_paths: 327015 at depth 4 of iter20
+  num_paths: 266191 at depth 5 of iter20
+  num_paths: 217700 at depth 6 of iter20
+  num_paths: 178610 at depth 7 of iter20
+  num_paths: 0 at depth 8 of iter20
+  ```
+
+Results 2:
+Tested with cornell_refraction_close.json. Comparing to cornell_refraction.json, it has one more cube at back of the camera so light can't escape the room.
+
+  ![SC1](img/sc_bar_close.png)
+  ```
+  num_paths: 588103 at depth 1 of iter18
+  num_paths: 552057 at depth 2 of iter18
+  num_paths: 522357 at depth 3 of iter18
+  num_paths: 493064 at depth 4 of iter18
+  num_paths: 464186 at depth 5 of iter18
+  num_paths: 437812 at depth 6 of iter18
+  num_paths: 413273 at depth 7 of iter18
+  num_paths: 0 at depth 8 of iter18
+  num_paths: 588112 at depth 1 of iter19
+  num_paths: 551931 at depth 2 of iter19
+  num_paths: 522363 at depth 3 of iter19
+  num_paths: 492947 at depth 4 of iter19
+  num_paths: 464198 at depth 5 of iter19
+  num_paths: 437899 at depth 6 of iter19
+  num_paths: 413139 at depth 7 of iter19
+  num_paths: 0 at depth 8 of iter19
+  num_paths: 588110 at depth 1 of iter20
+  num_paths: 552150 at depth 2 of iter20
+  num_paths: 522766 at depth 3 of iter20
+  num_paths: 493317 at depth 4 of iter20
+  num_paths: 464677 at depth 5 of iter20
+  num_paths: 438364 at depth 6 of iter20
+  num_paths: 413396 at depth 7 of iter20
+  num_paths: 0 at depth 8 of iter20
+  ```
+
+The average render time is higher with close room scene. Since there is a lot less light terminated during rendering, more kernels need to be launched at each render pass, causing higher render time.
+
+### BVH Reults
+
+BVH is constructed on CPU, then ray-scene intersection kernel iteratively looks for closest hit along the BVH Tree. BVH accept three arguments: number of bins to split per axis ( when constructing BVH), max leaf size acceptable, and max depth acceptable.
+
+*Test scene used is cow.obj, contains 2903 vertices, 5804 faces, and 1 diffuse material*
+
+*Config 0 is using a single volume containing the whole mesh.*
+
+#### Using max leaf count as bvh constraint
+
+```
+Max leaf count is set, max depth is generated on the fly.
+config 0: Single volume
+config 1: Bins per axis: 32, Max depth: 33, largest leaf size: 10
+config 2: Bins per axis: 32, Max depth: 22, largest leaf size: 27
+config 3: Bins per axis: 32, Max depth: 11, largest leaf size: 63
+config 4: Bins per axis: 32, Max depth: 10, largest leaf size: 120
+config 5: Bins per axis: 32, Max depth: 8, largest leaf size: 229
+```
+  ![maxleaf](img/max_leaf.png)
+
+#### Using max depth as bvh constraint
+```
+Max depth is set, max leaf count is generated on the fly.
+config 0: Single volume, 2995
+config 1: Bins per axis: 32, Max depth: 4, largest leaf size: 1253
+config 2: Bins per axis: 32, Max depth: 10, largest leaf size: 102
+config 3: Bins per axis: 32, Max depth: 20, largest leaf size: 30
+config 4: Bins per axis: 32, Max depth: 38, largest leaf size: 10
+config 5: Bins per axis: 32, Max depth: 100, largest leaf size: 162
+```
+  ![maxdepth](img/maxdepth.png)
+
+#### BVH Conclusion
+The BVH performance varies a lot given different tree construction configuration. Overall the 
+best BVH result is slight worse than adding a simple bounding volume culling. I think that BVH will show improvement over vanilla bounding volume when we use a much denser mesh with 10k or more vertices in it. 
+
+### Sorting by material type
+
+Another option is to sort by material type during each render pass so that each block will have similar performance. Here is the result. Tested with cornell_refraction scene.
+  ```
+  No sort: Not soring by material type.
+  One partition: Only group one type of material. Used for performance comparison
+  Full Partition: All materials are grouped by type. Using thrust::parition
+  Stable Partition: All materials are grouped by type. Using thrust::stable_parition
+  Full sort:  All materials types are sorted thrust::stable_sort
+  ```
+  ![matsort](img/matsort.png)
+
+  Turning on material sort hinders performance. I expect to that scenes with many more material types will see noticeable benefit from using this option.
 
-### (TODO: Your README)
+### 3rd-party code used
 
-*DO NOT* leave the README to the last minute! It is a crucial part of the
-project, and we will not be able to grade you without a good README.
+* https://github.com/tinyobjloader/tinyobjloader/
 
diff --git a/img/UI.png b/img/UI.png
diff --git a/img/basic.png b/img/basic.png
diff --git a/img/basic_obj.png b/img/basic_obj.png
diff --git a/img/bvh_ui.png b/img/bvh_ui.png
diff --git a/img/clang_update.png b/img/clang_update.png
diff --git a/img/cornell_cow.png b/img/cornell_cow.png
diff --git a/img/cover.png b/img/cover.png
diff --git a/img/file_UI.png b/img/file_UI.png
diff --git a/img/matsort.png b/img/matsort.png
diff --git a/img/max_leaf.png b/img/max_leaf.png
diff --git a/img/maxdepth.png b/img/maxdepth.png
diff --git a/img/refraction.png b/img/refraction.png
diff --git a/img/sc_bar.png b/img/sc_bar.png
diff --git a/img/sc_bar_close.png b/img/sc_bar_close.png
diff --git a/obj_files/box/issue-177.mtl b/obj_files/box/issue-177.mtl
@@ -0,0 +1,24 @@
+newmtl white
+Ka 0 0 0
+Kd 1 1 1
+Ks 0 0 0
+
+newmtl red
+Ka 0 0 0
+Kd 1 0 0
+Ks 0 0 0
+
+newmtl green
+Ka 0 0 0
+Kd 0 1 0
+Ks 0 0 0
+
+newmtl blue
+Ka 0 0 0
+Kd 0 0 1
+Ks 0 0 0
+
+newmtl light
+Ka 20 20 20
+Kd 1 1 1
+Ks 0 0 0
diff --git a/obj_files/box/issue-177.obj b/obj_files/box/issue-177.obj
@@ -0,0 +1,31 @@
+mtllib issue-177.mtl
+
+v 0.000000 2.000000 2.000000
+v 0.000000 0.000000 2.000000
+v 2.000000 0.000000 2.000000
+v 2.000000 2.000000 2.000000
+v 0.000000 2.000000 0.000000
+v 0.000000 0.000000 0.000000
+v 2.000000 0.000000 0.000000
+v 2.000000 2.000000 0.000000
+# 8 vertices
+
+g front cube
+usemtl white
+f 1 2 3 4
+g back cube
+# expects white material
+f 8 7 6 5
+g right cube
+usemtl red
+f 4 3 7 8
+g top cube
+usemtl white
+f 5 1 4 8
+g left cube
+usemtl green
+f 5 6 2 1
+g bottom cube
+usemtl white
+f 2 6 7 3
+# 6 elements
-Original file line number
+Diff line change
@@ Expand Up / @@ -23,7 +23,7 @@ build @@
     .LSOverride
     # Icon must end with two \r
-    Icon
+    Icon
     # Thumbnails
     ._*
@@ Expand Down Expand Up / @@ -189,7 +189,6 @@ install_manifest.txt @@
     *.slo
     *.lo
     *.o
-    *.obj
     # Precompiled Headers
     *.gch
@@ Expand Down Expand Up / @@ -276,7 +275,6 @@ artifacts/ @@
     *_i.h
     *.ilk
     *.meta
-    *.obj
     *.pch
     *.pdb
     *.pgc
@@ Expand Down @@