CIS565-Fall-2020 · gizemdal · Oct 18, 2020 · Oct 18, 2020 · Oct 19, 2020 · Oct 19, 2020
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -110,10 +110,10 @@ source_group(Headers FILES ${headers})
 source_group(Sources FILES ${sources})
 source_group(imgui FILES ${imgui})
 
-#add_subdirectory(stream_compaction)  # TODO: uncomment if using your stream compaction
+add_subdirectory(stream_compaction)  # TODO: uncomment if using your stream compaction
 
 cuda_add_executable(${CMAKE_PROJECT_NAME} ${sources} ${headers} ${imgui})
 target_link_libraries(${CMAKE_PROJECT_NAME}
     ${LIBRARIES}
-    #stream_compaction  # TODO: uncomment if using your stream compaction
+    stream_compaction  # TODO: uncomment if using your stream compaction
     )
diff --git a/README.md b/README.md
@@ -3,11 +3,101 @@ CUDA Denoiser For CUDA Path Tracer
 
 **University of Pennsylvania, CIS 565: GPU Programming and Architecture, Project 4**
 
-* (TODO) YOUR NAME HERE
-* Tested on: (TODO) Windows 22, i7-2222 @ 2.22GHz 22GB, GTX 222 222MB (Moore 2222 Lab)
+* Name: Gizem Dal
+  * [LinkedIn](https://www.linkedin.com/in/gizemdal), [personal website](https://www.gizemdal.com/)
+* Tested on: Predator G3-571 Intel(R) Core(TM) i7-7700HQ CPU @ 2.80 GHz 2.81 GHz - Personal computer
 
-### (TODO: Your README)
+<img src="img/renders/readme_reg.png" alt="reg" width=400> <img src="img/renders/readme_denoised.png" alt="denoised" width=400>
 
-*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.
+*Iterations: 10, Filter Size: 10, Blur Size: 63, Color Weight: 38.008, Normal Weight: 0.407, Position Weight: 3.862*
 
+## Project Description ##
+
+This project focuses on implementing a pathtracing denoiser that uses geometry buffers (G-buffers) to guide a smoothing filter. The technique is based on the [Edge-Avoiding A-Trous Wavelet Transform for fast Global Illumination Filtering](https://jo.dreggn.org/home/2010_atrous.pdf) paper by Dammertz, Sewtz, Hanika, and Lensch.
+
+**Features **
+
+* GBuffer Visualization
+  * Position
+  * Normal
+  * Material base color
+* Adjustable filter & blur size
+* Guided denoiser
+
+## GBuffer Visualization ##
+
+GBuffers include scene geometry information such as per-pixel normals and per-pixel positions, as well as surface color for preserving detail in mapped or procedural textures. The current implementation stores per-pixel metrics only from the first bounce.
+
+Position | Normal | Base Color
+:---: | :---: | :---: 
+<img src="img/renders/gbuffer_pos.png" alt="pos" width=300> | <img src="img/renders/gbuffer_nor.png" alt="nor" width=300> | <img src="img/renders/gbuffer_col.png" alt="col" width=300>
+
+## Denoising Parameters ##
+
+Denoising parameters such as filter and blur sizes, number of iterations, color/normal/position weights are adjustable from the provided [Imgui](https://github.com/ocornut/imgui) GUI.
+
+**Blur Size**
+
+The examples below use the following other parameter values: *Filter Size = 5; Iter = 2; Col_W = 11.789; Nor_W = 0.610; Pos_W = 0.407*
+
+Blur=10  | Blur=33 | Blur=80 | Blur=185
+:---: | :---: | :---: | :---: 
+<img src="img/renders/blur_10.png" alt="pos" width=300> | <img src="img/renders/blur_33.png" alt="nor" width=300> | <img src="img/renders/blur_80.png" alt="col" width=300> | <img src="img/renders/blur_185.png" alt="col" width=300>
+
+Increasing the blur size allows more denoiser iterations since the blur size determines the largest expansion width the filter can reach. Applying more iterations result in smoother images, especially for very small number of path tracer iterations (which in this example is only 2). However, increasing the blur size has performance implications as well (check the Performance Analysis section below).
+
+**Color Weight**
+
+The examples below use the following other parameter values: *Filter Size = 5; Iter = 2; Blur Size = 80; Nor_W = 0.610; Pos_W = 0.407*
+
+Col_W=1.423  | Col_W=4.675 | Col_W=15.244 | Col_W=30.285
+:---: | :---: | :---: | :---: 
+<img src="img/renders/col_1.423.png" alt="pos" width=300> | <img src="img/renders/col_4.675.png" alt="nor" width=300> | <img src="img/renders/col_15.244.png" alt="col" width=300> | <img src="img/renders/col_30.285.png" alt="col" width=300>
+
+The results suggest that increasing the color weight results in smoother denoised results. Lower color weights result in denoised renders with more "fireflies" while larger weights give smoother results. However, it is important to mention that the impact of color weight may depend from implementation to implementation. The current adaptation from the A-Trous approach halves the color weight at each denoise blur iteration in order to smoothen smaller smaller illumination variations, as suggested by the paper.
+
+**Light Size**
+
+The examples below use the following other parameter values: *Filter Size = 5; Iter = 10; Blur Size = 63; Col_W = 28.455 Nor_W = 0.813; Pos_W = 3.862, Light intensity = 1*
+
+Light Width = 3 | Light Width = 5 | Light Width = 7 | Light Width = 10
+:---: | :---: | :---: | :---: 
+<img src="img/renders/3_light.png" alt="pos" width=300> | <img src="img/renders/5_light.png" alt="nor" width=300> | <img src="img/renders/7_light.png" alt="col" width=300> | <img src="img/renders/10_light.png" alt="col" width=300>
+
+However, increasing the light intensity may result in less smoother results with a lot of fireflies. The example below use a light width of 3 and intensity of 5, keeping the other parameters constant.
+
+<img src="img/renders/3_light_5_50.png" alt="pos" width=300>
+
+**Filter Size**
+
+For the purpose of analyzing the effect of different sizes, I implemented the denoiser filter size to be adjustable rather than set to 5 as constant. The examples below use the following parameters: *Col_W = 16.667 Nor_W = 0.610; Pos_W = 0.813* The blur sizes are adjusted to allow the same number of blur iterations for different filter sizes.
+
+Filter = 5, Blur = 80 | Filter = 9, Blur = 80 | Filter = 21, Blur = 81 | Filter = 43, Blur = 103
+:---: | :---: | :---: | :---: 
+<img src="img/renders/filter_5.png" alt="pos" width=300> | <img src="img/renders/filter_9.png" alt="nor" width=300> | <img src="img/renders/filter_21_81.png" alt="col" width=300> | <img src="img/renders/filter_43_103.png" alt="col" width=300>
+
+The results suggest that changing the filter size doesn't seem to have a significant impact on denoiser results.
+
+## Performance Analysis ##
+
+I used a GPU timer to conduct my performance analysis on different settings in the denoiser. This timer is wrapped up as a performance timer class, which uses the CUDAEvent library, in order to measure the time cost conveniently. The timer is started right before the denoiser computation and is terminated once it ends. The measured time excludes memory operations such as cudaMalloc() and cudaMemset().
+
+Measured runtimes are noted in miliseconds.
+
+**Material Type**
+
+Diffuse | Specular | Glossy | Fresnel
+:---: | :---: | :---: | :---: 
+23.068 | 23.1178 | 23.0083 | 22.999
+
+**Filter Size**
+
+5 | 9 | 21 | 43
+:---: | :---: | :---: | :---: 
+23.1178 | 73.1147 | 323.145 | 1343.26
+
+**Blur Size**
+
+16 | 33 | 80 | 173
+:---: | :---: | :---: | :---: 
+9.5744 | 18.6659 | 23.1178 | 27.8777
diff --git a/img/renders/10_light.png b/img/renders/10_light.png
diff --git a/img/renders/10_light1.png b/img/renders/10_light1.png
diff --git a/img/renders/3_light.png b/img/renders/3_light.png
diff --git a/img/renders/3_light1.png b/img/renders/3_light1.png
diff --git a/img/renders/3_light_5.png b/img/renders/3_light_5.png
diff --git a/img/renders/3_light_5_50.png b/img/renders/3_light_5_50.png
diff --git a/img/renders/5_light.png b/img/renders/5_light.png
diff --git a/img/renders/5_light1.png b/img/renders/5_light1.png
diff --git a/img/renders/7_light.png b/img/renders/7_light.png
diff --git a/img/renders/7_light1.png b/img/renders/7_light1.png
diff --git a/img/renders/7_light_5.png b/img/renders/7_light_5.png
diff --git a/img/renders/7_light_5_50.png b/img/renders/7_light_5_50.png
diff --git a/img/renders/blur_10.png b/img/renders/blur_10.png
diff --git a/img/renders/blur_185.png b/img/renders/blur_185.png
diff --git a/img/renders/blur_33.png b/img/renders/blur_33.png
diff --git a/img/renders/blur_80.png b/img/renders/blur_80.png
diff --git a/img/renders/col_1.423.png b/img/renders/col_1.423.png
diff --git a/img/renders/col_15.244.png b/img/renders/col_15.244.png
diff --git a/img/renders/col_30.285.png b/img/renders/col_30.285.png
diff --git a/img/renders/col_38.415.png b/img/renders/col_38.415.png
diff --git a/img/renders/col_4.675.png b/img/renders/col_4.675.png
diff --git a/img/renders/filter_21.png b/img/renders/filter_21.png
diff --git a/img/renders/filter_21_81.png b/img/renders/filter_21_81.png
diff --git a/img/renders/filter_43.png b/img/renders/filter_43.png
diff --git a/img/renders/filter_43_103.png b/img/renders/filter_43_103.png
diff --git a/img/renders/filter_5.png b/img/renders/filter_5.png
diff --git a/img/renders/filter_9.png b/img/renders/filter_9.png
diff --git a/img/renders/gbuffer_col.png b/img/renders/gbuffer_col.png
diff --git a/img/renders/gbuffer_nor.png b/img/renders/gbuffer_nor.png
diff --git a/img/renders/gbuffer_pos.png b/img/renders/gbuffer_pos.png
diff --git a/img/renders/iter_2.png b/img/renders/iter_2.png
diff --git a/img/renders/iter_2_denoised_16.png b/img/renders/iter_2_denoised_16.png
diff --git a/img/renders/iter_2_denoised_61.png b/img/renders/iter_2_denoised_61.png
diff --git a/img/renders/iter_2_denoised_79.png b/img/renders/iter_2_denoised_79.png
diff --git a/img/renders/iter_2_final.png b/img/renders/iter_2_final.png
diff --git a/img/renders/iter_3_final.png b/img/renders/iter_3_final.png
diff --git a/img/renders/iter_9_final.png b/img/renders/iter_9_final.png
diff --git a/img/renders/no_blur.png b/img/renders/no_blur.png
diff --git a/img/renders/readme_denoised.png b/img/renders/readme_denoised.png
diff --git a/img/renders/readme_reg.png b/img/renders/readme_reg.png
diff --git a/scenes/cornell.txt b/scenes/cornell.txt
@@ -6,7 +6,7 @@ SPECRGB     0 0 0
 REFL        0
 REFR        0
 REFRIOR     0
-EMITTANCE   5
+EMITTANCE   1
 
 // Diffuse white
 MATERIAL 1
@@ -43,16 +43,16 @@ MATERIAL 4
 RGB         .98 .98 .98
 SPECEX      0
 SPECRGB     .98 .98 .98
-REFL        1
-REFR        0
-REFRIOR     0
+REFL        0
+REFR        1
+REFRIOR     2.5
 EMITTANCE   0
 
 // Camera
 CAMERA
 RES         800 800
 FOVY        45
-ITERATIONS  5000
+ITERATIONS  2
 DEPTH       8
 FILE        cornell
 EYE         0.0 5 10.5
@@ -66,7 +66,7 @@ cube
 material 0
 TRANS       0 10 0
 ROTAT       0 0 0
-SCALE       3 .3 3
+SCALE       10 .3 10
 
 // Floor
 OBJECT 1

diff --git a/scenes/cornell_ceiling_light.txt b/scenes/cornell_ceiling_light.txt
@@ -38,24 +38,54 @@ REFR        0
 REFRIOR     0
 EMITTANCE   0
 
-// Specular white
+// Specular blue
 MATERIAL 4
-RGB         .98 .98 .98
+RGB         .65 .65 .98
+SPECEX      0
+SPECRGB     .65 .65 .98
+REFL        1
+REFR        0
+REFRIOR     0
+EMITTANCE   0
+
+// Fresnel magenta
+MATERIAL 5
+RGB         .98 .65 .98
 SPECEX      0
-SPECRGB     .98 .98 .98
+SPECRGB     .98 .65 .98
+REFL        0
+REFR        1
+REFRIOR     2.5
+EMITTANCE   0
+
+// Glossy cyan
+MATERIAL 6
+RGB         .65 .98 .98
+SPECEX      7.5
+SPECRGB     .65 .98 .98
 REFL        1
 REFR        0
 REFRIOR     0
 EMITTANCE   0
 
+// Diffuse yellow
+MATERIAL 7
+RGB         .98 .98 .65
+SPECEX      0
+SPECRGB     .98 .98 .65
+REFL        0
+REFR        0
+REFRIOR     0
+EMITTANCE   0
+
 // Camera
 CAMERA
 RES         800 800
 FOVY        45
 ITERATIONS  10
 DEPTH       8
 FILE        cornell
-EYE         0.0 5 10.5
+EYE         0.0 5 9.5
 LOOKAT      0 5 0
 UP          0 1 0
 
@@ -66,15 +96,15 @@ cube
 material 0
 TRANS       0 10 0
 ROTAT       0 0 0
-SCALE       10 .3 10
+SCALE       20 .3 10
 
 // Floor
 OBJECT 1
 cube
 material 1
 TRANS       0 0 0
 ROTAT       0 0 0
-SCALE       10 .01 10
+SCALE       20 .01 10
 
 // Ceiling
 OBJECT 2
@@ -90,28 +120,52 @@ cube
 material 1
 TRANS       0 5 -5
 ROTAT       0 90 0
-SCALE       .01 10 10
+SCALE       .01 10 20
 
 // Left wall
 OBJECT 4
 cube
 material 2
-TRANS       -5 5 0
+TRANS       -10 5 0
 ROTAT       0 0 0
 SCALE       .01 10 10
 
 // Right wall
 OBJECT 5
 cube
 material 3
-TRANS       5 5 0
+TRANS       10 5 0
 ROTAT       0 0 0
 SCALE       .01 10 10
 
-// Sphere
+// Mirror Sphere
 OBJECT 6
 sphere
 material 4
-TRANS       -1 4 -1
+TRANS       -7.5 4 -2
+ROTAT       0 0 0
+SCALE       3 3 3
+
+// Diffuse Sphere
+OBJECT 7
+sphere
+material 7
+TRANS       -2.5 4 -2
 ROTAT       0 0 0
 SCALE       3 3 3
+
+// Fresnel Sphere
+OBJECT 8
+sphere
+material 5
+TRANS       2.5 4 -2
+ROTAT       0 0 0
+SCALE       3 3 3
+
+// Glossy Sphere
+OBJECT 9
+sphere
+material 6
+TRANS       7.5 4 -2
+ROTAT       0 0 0
+SCALE       3 3 3
diff --git a/src/interactions.h b/src/interactions.h
@@ -40,8 +40,36 @@ glm::vec3 calculateRandomDirectionInHemisphere(
         + sin(around) * over * perpendicularDirection2;
 }
 
+/*
+* Computes sampled glossy reflection direction.
+*/
+__host__ __device__
+glm::vec3 calculateImperfectSpecularDirection(
+    glm::vec3 normal, float spec_exp, thrust::default_random_engine& rng) {
+    thrust::uniform_real_distribution<float> u01(0, 1);
+    float theta = glm::acos(glm::pow(u01(rng), 1.f / (spec_exp + 1.f)));
+    float phi = TWO_PI * u01(rng);
+    glm::vec3 sample_dir(cos(phi) * sin(theta), sin(phi) * sin(theta), cos(theta));
+
+    // Compute tangent space
+    glm::vec3 tangent;
+    glm::vec3 bitangent;
+
+    if (glm::abs(normal.x) > glm::abs(normal.y)) {
+        tangent = glm::vec3(-normal.z, 0.f, normal.x) / glm::sqrt(normal.x * normal.x + normal.z * normal.z);
+    }
+    else {
+        tangent = glm::vec3(0, normal.z, -normal.y) / glm::vec3(normal.y * normal.y + normal.z * normal.z);
+    }
+    bitangent = glm::cross(normal, tangent);
+
+    // Transform sample from specular space to tangent space
+    glm::mat3 transform(tangent, bitangent, normal);
+    return glm::normalize(transform * sample_dir);
+}
+
 /**
- * Simple ray scattering with diffuse and perfect specular support.
+ * Simple ray scattering with diffuse, perfect specular, glossy and fresnel dielectric support.
  */
 __host__ __device__
 void scatterRay(
@@ -52,8 +80,43 @@ void scatterRay(
         thrust::default_random_engine &rng) {
     glm::vec3 newDirection;
     if (m.hasReflective) {
-        newDirection = glm::reflect(pathSegment.ray.direction, normal);
-    } else {
+        if (m.specular.exponent > 0.f) {
+            // Glossy
+            newDirection = calculateImperfectSpecularDirection(normal, m.specular.exponent, rng);
+        }
+        else {
+            // Mirror
+            newDirection = glm::reflect(pathSegment.ray.direction, normal);
+        }
+    }
+    else if (m.hasRefractive) {
+        // Fresnel
+        float cosine;
+        float reflect_prob;
+        bool entering = glm::dot(pathSegment.ray.direction, normal) < 0;
+        float etaI = entering ? 1.f : m.indexOfRefraction;
+        float etaT = entering ? m.indexOfRefraction : 1.f;
+        float eta = etaI / etaT;
+        cosine = entering ? -glm::dot(pathSegment.ray.direction, normal) / glm::length(pathSegment.ray.direction) :
+            m.indexOfRefraction * glm::dot(pathSegment.ray.direction, normal) / glm::length(pathSegment.ray.direction);
+        newDirection = glm::refract(pathSegment.ray.direction, normal, eta);
+        if (glm::length(newDirection) == 0.f) {
+            reflect_prob = 1.f;
+        }
+        else {
+            float R0 = (etaI - etaT) / (etaI + etaT);
+            R0 *= R0;
+            reflect_prob = R0 + (1.f - R0) * glm::pow(1.f - cosine, 5.f);
+        }
+
+        thrust::uniform_real_distribution<float> u01(0, 1);
+        float prob = u01(rng);
+        if (prob < reflect_prob) {
+            newDirection = glm::reflect(pathSegment.ray.direction, normal);
+        }
+    } 
+    else {
+        // Diffuse
         newDirection = calculateRandomDirectionInHemisphere(normal, rng);
     }