Project 3: Zhuohao Lin

.gitignore

@@ -23,7 +23,8 @@ build
 .LSOverride
 
 # Icon must end with two \r
-Icon
+Icon
+
 
 # Thumbnails
 ._*
@@ -189,7 +190,6 @@ install_manifest.txt
 *.slo
 *.lo
 *.o
-*.obj
 
 # Precompiled Headers
 *.gch

CMakeLists.txt

@@ -73,6 +73,8 @@ set(headers
     src/sceneStructs.h
     src/preview.h
     src/utilities.h
+    src/ThirdPartyLib/tiny_obj_loader.h
+    src/bvhTree.h
     src/ImGui/imconfig.h
 
 	src/ImGui/imgui.h
@@ -95,6 +97,8 @@ set(sources
     src/scene.cpp
     src/preview.cpp
     src/utilities.cpp
+    src/ThirdPartyLib/tiny_obj_loader.cc
+    src/bvhTree.cu
 
     src/ImGui/imgui.cpp 
       src/ImGui/imgui_demo.cpp 

README.md

@@ -3,11 +3,44 @@ 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)
+* Zhuohao Lin
+  * [LinkedIn](https://www.linkedin.com/in/zhuohao-lin-960b54194/)
+* Tested on: Windows 10, i7-10875H @ 2.30GHz 16GB, NVIDIA Grforce RTX 2060 6GB (personal machine)
 
-### (TODO: Your README)
+# Overview
+This is a GPU based path tracer. The project contains both visual and performance improvements so that mutiple objects with different kinds of materials can be rendered quickly.
+![](img/cornell.2022-10-08_06-59-29z.5000samp.png)
 
-*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.
+# Features
+### `Arbitrary mesh loading and rendering with obj file`
+![](img/cornell.2022-10-08_20-44-19z.5000samp.png)
 
+### `Antialiasing`
+Before Antialiasing            |  After Antialiasing 
+:-------------------------:|:-------------------------:
+![](img/beforeAntialiasing.png)  |  ![](img/afterAntialiasing.png)
+
+### `Refraction material`
+Index of refraction of cube and sphere: 1.5
+![](img/cornell.2022-10-08_22-12-30z.5000samp.png)
+
+### `Bounding volume hierarchy acceleration data structure`
+I implemented bounding volume hierarchy data structure in order to accelerate the intersection testing process. This data structure organize primitives into a binary tree based on their bounding box. There are various ways to split primitives. What I did is simply divide primitives into equal subsets. The BVH tree was built in CPU and then passed into GPU in a linear array. When doing intersection tests, first find box intersections within BVH tree apparently improve performance since a lot of primitives are abandoned.
+
+# Performance Analysis
+
+## Cache the First Bounce
+For the first intersection of every iteration, it's always the same without any doubts. Therefore, I cache the first intersection data so that the computation can be skipped in every iteration except the first one. To see how much performance this brings, I make a graph as below (all data are got from the same scene)
+
+![](img/cacheFirstBounce.PNG)
+
+By caching the first bounce in the scene, we always get a higher FPS than no cache. However, as the max ray depth increases, the percentage increase in FPS is going down.
+
+
+## Bounding Volume Hierarchy
+I put 3 objects with different number of faces in the same scene for performance comparison. In order to keep the number of intersections as close as possible, I set 3 objects in similar sizes.
+
+![](img/bvhPerformance.PNG)
+
+It's obvious that BVH tree brings a huge performance improvement. The more the number of faces a mesh has, the lower the FPS will be. However, the FPS is dropping much slower using BVH than not using BVH. This is expected since BVH is a binary tree. The time cost to search intersections using BVH is roughly log(N) but N for not using BVH. <br/>
+Note: Search intersections in BVH tree is roughly log(N) because it can get into different leaf nodes if some bounding boxes overlap.

scenes/antialiasing.txt

@@ -0,0 +1,147 @@
+// Emissive material (light)
+MATERIAL 0
+RGB         0.992 0.518 0.122
+SPECEX      0
+SPECRGB     0 0 0
+REFL        0
+REFR        0
+REFRIOR     0
+EMITTANCE   5
+
+// Diffuse white
+MATERIAL 1
+RGB         .98 .98 .98
+SPECEX      0
+SPECRGB     0 0 0
+REFL        0
+REFR        0
+REFRIOR     0
+EMITTANCE   0
+
+// Diffuse red
+MATERIAL 2
+RGB         .8 .8 1
+SPECEX      0
+SPECRGB     0 0 0
+REFL        0
+REFR        0
+REFRIOR     0
+EMITTANCE   0
+
+// Diffuse green
+MATERIAL 3
+RGB         .8 .8 1
+SPECEX      0
+SPECRGB     0 0 0
+REFL        0
+REFR        0
+REFRIOR     0
+EMITTANCE   0
+
+// Specular white
+MATERIAL 4
+RGB         .98 .98 .98
+SPECEX      0
+SPECRGB     .98 .98 .98
+REFL        1
+REFR        0
+REFRIOR     0
+EMITTANCE   0
+
+// diffuse white
+MATERIAL 5
+RGB         0.98 .98 .98
+SPECEX      0
+SPECRGB     .91 .89 .867
+REFL        0
+REFR        0
+REFRIOR     1.5
+EMITTANCE   0
+
+// Specular white
+MATERIAL 6
+RGB         .98 .98 .98
+SPECEX      0
+SPECRGB     .98 .98 .98
+REFL        0
+REFR        0
+REFRIOR     0
+EMITTANCE   0
+
+// Refractive white
+MATERIAL 6
+RGB         .98 .98 .98
+SPECEX      0
+SPECRGB     .98 .98 0
+REFL        1
+REFR        1
+REFRIOR     1.5
+EMITTANCE   0
+
+// Camera
+CAMERA
+RES         1080 1080
+FOVY        45
+ITERATIONS  500
+DEPTH       8
+FILE        cornell
+EYE         0.0 5 10.5
+LOOKAT      0 5 0
+UP          0 1 0
+
+
+// Ceiling light
+OBJECT 0
+cube
+material 0
+TRANS       0 10 0
+ROTAT       0 0 0
+SCALE       3 .3 3
+
+// Floor
+OBJECT 1
+cube
+material 1
+TRANS       0 0 0
+ROTAT       0 0 0
+SCALE       10 .01 10
+
+// Ceiling
+OBJECT 2
+cube
+material 1
+TRANS       0 10 0
+ROTAT       0 0 90
+SCALE       .01 10 10
+
+// Back wall
+OBJECT 3
+cube
+material 1
+TRANS       0 5 -5
+ROTAT       0 90 0
+SCALE       .01 10 10
+
+// Left wall
+OBJECT 4
+cube
+material 2
+TRANS       -5 5 0
+ROTAT       0 0 0
+SCALE       .01 10 10
+
+// Right wall
+OBJECT 5
+cube
+material 3
+TRANS       5 5 0
+ROTAT       0 0 0
+SCALE       .01 10 10
+
+// Sphere
+OBJECT 6
+../scenes/objFiles/cube.obj
+material 5
+TRANS       0 4 0
+ROTAT       0 30 0
+SCALE       4 4 4

scenes/cornell.txt

@@ -6,7 +6,7 @@ SPECRGB     0 0 0
 REFL        0
 REFR        0
 REFRIOR     0
-EMITTANCE   5
+EMITTANCE   10
 
 // Diffuse white
 MATERIAL 1
@@ -48,6 +48,26 @@ REFR        0
 REFRIOR     0
 EMITTANCE   0
 
+// Specular white
+MATERIAL 5
+RGB         .98 .98 .98
+SPECEX      0
+SPECRGB     .98 .98 .98
+REFL        0
+REFR        0
+REFRIOR     0
+EMITTANCE   0
+
+// Refractive yellow
+MATERIAL 6
+RGB         .98 .98 .98
+SPECEX      0
+SPECRGB     .98 .98 0
+REFL        1
+REFR        1
+REFRIOR     1.5
+EMITTANCE   0
+
 // Camera
 CAMERA
 RES         800 800
@@ -110,8 +130,58 @@ SCALE       .01 10 10
 
 // Sphere
 OBJECT 6
-sphere
-material 4
-TRANS       -1 4 -1
+../scenes/objFiles/wahoo.obj
+material 6
+TRANS       2 4 0
+ROTAT       0 0 0
+SCALE       0.35 0.35 0.35
+
+
+OBJECT 7
+../scenes/objFiles/wahoo.obj
+material 5
+TRANS       0 4 2
+ROTAT       0 0 0
+SCALE       0.35 0.35 0.35
+
+OBJECT 8
+../scenes/objFiles/wahoo.obj
+material 5
+TRANS       2 1 0
+ROTAT       0 0 0
+SCALE       0.35 0.35 0.35
+
+OBJECT 9
+../scenes/objFiles/wahoo.obj
+material 2
+TRANS       0 1 2
+ROTAT       0 0 0
+SCALE       0.35 0.35 0.35
+
+OBJECT 10
+../scenes/objFiles/wahoo.obj
+material 5
+TRANS       3 1 2
+ROTAT       0 0 0
+SCALE       0.35 0.35 0.35
+
+OBJECT 11
+../scenes/objFiles/wahoo.obj
+material 5
+TRANS       -2 4 -2
+ROTAT       0 0 0
+SCALE       0.35 0.35 0.35
+
+OBJECT 12
+../scenes/objFiles/Caitlyn.obj
+material 5
+TRANS       1 1 0
+ROTAT       0 0 0
+SCALE       2 2 2
+
+OBJECT 13
+../scenes/objFiles/melina.obj
+material 5
+TRANS       -1 1 0
 ROTAT       0 0 0
-SCALE       3 3 3
+SCALE       2 2 2