Project 5: Jason Xie

.gitignore

@@ -0,0 +1,2 @@
+bin
+build

.vscode/launch.json

@@ -0,0 +1,28 @@
+{
+    // Use IntelliSense to learn about possible attributes.
+    // Hover to view descriptions of existing attributes.
+    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "Attach to Process",
+            "type": "cppdbg",
+            "request": "attach",
+            "program": "${workspaceFolder}/bin/vulkan_grass_rendering",
+            "processId": "${command:pickProcess}", 
+            "MIMode": "gdb",
+            "setupCommands": [
+                {
+                    "description": "Enable pretty-printing for gdb",
+                    "text": "-enable-pretty-printing",
+                    "ignoreFailures": true
+                },
+                {
+                    "description": "Set Disassembly Flavor to Intel",
+                    "text": "-gdb-set disassembly-flavor intel",
+                    "ignoreFailures": true
+                }
+            ],
+        }
+    ]
+}

.vscode/settings.json

@@ -0,0 +1,17 @@
+{
+    "ros.distro": "humble",
+    "files.associations": {
+        "*.sdf": "xml",
+        "*.world": "xml",
+        "*.gltf": "json",
+        "array": "cpp",
+        "string": "cpp",
+        "string_view": "cpp",
+        "ranges": "cpp",
+        "*.ipp": "cpp",
+        "bitset": "cpp",
+        "initializer_list": "cpp",
+        "utility": "cpp",
+        "valarray": "cpp"
+    }
+}

README.md

@@ -1,12 +1,126 @@
-Vulkan Grass Rendering
+Touching Grass in Vulkan
 ==================================
 
-**University of Pennsylvania, CIS 565: GPU Programming and Architecture, Project 5**
+![grass](img/submission/grass.gif)
+Jason Xie, October 2023
 
-* (TODO) YOUR NAME HERE
-* Tested on: (TODO) Windows 22, i7-2222 @ 2.22GHz 22GB, GTX 222 222MB (Moore 2222 Lab)
+## About
 
-### (TODO: Your README)
+A grass simulation in Vulkan. 
 
-*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.
+This project implements the paper [Responsive Real-Time Grass Rendering for General 3D Scenes](https://www.cg.tuwien.ac.at/research/publications/2017/JAHRMANN-2017-RRTG/JAHRMANN-2017-RRTG-draft.pdf), including Bezier curve grass blades, physical models for grass motion, and culling.
+
+## Features
+
+### 🌿 Bezier Curve Grass Blades
+
+Grass is represented as Bezier curves, where $v_0, v_1, v_2, v_3$ are the control points. In addition to these control points, the direction, height, width, and the "up" vector are also stored, resulting in four vec4s per grass blade.
+
+![bezier](img/blade_model.jpg)
+
+To draw the grass, vertices from the initial quad is refined through the tessellation shader. First, two separate Bezier curves are generated for each side of the grass blade. Then, the vertex position is determined by interpolating between the two curves.
+
+![shape](img/shape.png)
+
+### 🌿 Physical Models
+
+![physics](img/physics.png)
+
+Grass motion is modeled as displacements of the grass tip $v_2$ due to a comination of forces.
+
+**🌎️ Gravity**
+
+Gravity is simulated as a combination of *environmental gravity* and *frontal gravity*:
+
+$g = g_e + g_f$
+
+$g_f = \frac{1}{4} ||g_e|| f$
+
+**🌬️ Wind**
+
+The deflection of grass due to wind is modeled as a function of wind magnitude and grass alignment with the wind direction:
+
+$w = w_i(v_0) \theta(w_i(v_o), h)$
+
+Wind vector is modeled as a function of position and time, and it is layered using progressively smaller sinusoids.
+
+![wind](img/submission/grass1.gif)
+
+**🪃 Recovery**
+
+Elastic forces that help the grass bounce back is modeled using Hooke's law:
+
+$r = (I_{v_2} - v_2) s$
+
+### 🌿 Culling
+
+![culling](img/submission/grass2.gif)
+
+To allow for fast simulations, grass blades are culled through a combination of orientation culling, frustum culling and distance culling.
+
+**Orientation Culling**
+
+Grass blades that are not facing the camera are culled. This is done by checking the angle between the camera direction and the grass blade direction.
+
+**Frustum Culling**
+
+Grass blades that are outside of the view frustum are culled. Culling is performed by checking the intersection between the grass blade control points and the view frustum.
+
+**Distance Culling**
+
+Grass blades that are too far away from the camera are culled. 
+
+## Performance Analysis
+
+Let's analyze the impace of culling and number of grass blades on the performance of the simulation.
+
+**All Culling**
+
+| Number of Grass Blades | FPS |
+| ---------------------- | --- |
+| 2^22                   | 34  |
+| 2^20                   | 90  |
+| 2^18                   | 250 |
+
+**No Culling**
+
+| Number of Grass Blades | FPS |
+| ---------------------- | --- |
+| 2^22                   | 9  |
+| 2^20                   | 32  |
+| 2^18                   | 100  |
+
+**Orientation Culling**
+
+| Number of Grass Blades | FPS |
+| ---------------------- | --- |
+| 2^22                   | 9  |
+| 2^20                   | 30  |
+| 2^18                   | 80  |
+
+**Frustum Culling**
+
+| Number of Grass Blades | FPS |
+| ---------------------- | --- |
+| 2^22                   | 35  |
+| 2^20                   | 92  |
+| 2^18                   | 250  |
+
+**Distance Culling**
+
+| Number of Grass Blades | FPS |
+| ---------------------- | --- |
+| 2^22                   | 8  |
+| 2^20                   | 32  |
+| 2^18                   | 78  |
+
+![culling](img/submission/perf_cull.png)
+
+From the analysis, it appears that frustrum culling has the most impact on FPS. This is likely because in a large scene, the vast majority of blades will be hidden from view. 
+
+## Build & Run
+
+```bash
+bash build.sh debug
+cd bin && ./vulkan_grass_rendering
+```

build.sh

@@ -0,0 +1,28 @@
+#!/bin/bash
+
+# Create build directory if it doesn't exist
+mkdir -p build
+
+# Change into the build directory
+cd build
+
+# Default build type to Release
+build_type="Release"
+
+# Check for argument "debug" to change build type
+if [ "$1" == "debug" ]; then
+  echo "Building in debug mode"
+  build_type="Debug"
+fi
+
+# Run cmake with the specified build type
+cmake -DCMAKE_BUILD_TYPE=$build_type ..
+
+# Build the project with dbg if debug was specified
+if [ "$1" == "debug" ]; then
+  make dbg=1
+else
+  make
+fi
+
+# recursively move bin dir/ into build/

src/Blades.cpp

@@ -14,6 +14,9 @@ Blades::Blades(Device* device, VkCommandPool commandPool, float planeDim) : Mode
         Blade currentBlade = Blade();
 
         glm::vec3 bladeUp(0.0f, 1.0f, 0.0f);
+        // perturb up vector
+        bladeUp.x += (generateRandomFloat() - 0.5f) * 0.2f;
+        bladeUp.z += (generateRandomFloat() - 0.5f) * 0.2f;
 
         // Generate positions and direction (v0)
         float x = (generateRandomFloat() - 0.5f) * planeDim;
@@ -45,7 +48,7 @@ Blades::Blades(Device* device, VkCommandPool commandPool, float planeDim) : Mode
     indirectDraw.firstInstance = 0;
 
     BufferUtils::CreateBufferFromData(device, commandPool, blades.data(), NUM_BLADES * sizeof(Blade), VK_BUFFER_USAGE_STORAGE_BUFFER_BIT, bladesBuffer, bladesBufferMemory);
-    BufferUtils::CreateBuffer(device, NUM_BLADES * sizeof(Blade), VK_BUFFER_USAGE_STORAGE_BUFFER_BIT, VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT, culledBladesBuffer, culledBladesBufferMemory);
+    BufferUtils::CreateBuffer(device, NUM_BLADES * sizeof(Blade), VK_BUFFER_USAGE_STORAGE_BUFFER_BIT | VK_BUFFER_USAGE_VERTEX_BUFFER_BIT, VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT, culledBladesBuffer, culledBladesBufferMemory);
     BufferUtils::CreateBufferFromData(device, commandPool, &indirectDraw, sizeof(BladeDrawIndirect), VK_BUFFER_USAGE_STORAGE_BUFFER_BIT | VK_BUFFER_USAGE_INDIRECT_BUFFER_BIT, numBladesBuffer, numBladesBufferMemory);
 }
 

src/Blades.h

@@ -4,7 +4,7 @@
 #include <array>
 #include "Model.h"
 
-constexpr static unsigned int NUM_BLADES = 1 << 13;
+constexpr static unsigned int NUM_BLADES = 1 << 18;
 constexpr static float MIN_HEIGHT = 1.3f;
 constexpr static float MAX_HEIGHT = 2.5f;
 constexpr static float MIN_WIDTH = 0.1f;

src/BufferUtils.cpp

@@ -1,5 +1,6 @@
 #include "BufferUtils.h"
 #include "Instance.h"
+#include <cstring>
 
 void BufferUtils::CreateBuffer(Device* device, VkDeviceSize size, VkBufferUsageFlags usage, VkMemoryPropertyFlags properties, VkBuffer& buffer, VkDeviceMemory& bufferMemory) {
     // Create buffer

src/CMakeLists.txt

@@ -8,7 +8,7 @@ file(GLOB IMAGES
 
 foreach(IMAGE ${IMAGES})
     get_filename_component(fname ${IMAGE} NAME)
-    configure_file(${IMAGE} ${CMAKE_CURRENT_BINARY_DIR}/images/${fname} COPYONLY)
+    configure_file(${IMAGE} ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/images/${fname} COPYONLY)
 endforeach()
 
 file(GLOB_RECURSE SHADER_SOURCES
@@ -30,8 +30,10 @@ else(WIN32)
     target_link_libraries(vulkan_grass_rendering ${CMAKE_THREAD_LIBS_INIT})
 endif(WIN32)
 
+set(COMPILED_SHADERS "")
+
 foreach(SHADER_SOURCE ${SHADER_SOURCES})
-    set(SHADER_DIR ${CMAKE_CURRENT_BINARY_DIR}/shaders)
+    set(SHADER_DIR ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/shaders)
 
     if(WIN32)
         get_filename_component(fname ${SHADER_SOURCE} NAME)
@@ -42,11 +44,26 @@ foreach(SHADER_SOURCE ${SHADER_SOURCES})
         )
         ExternalTarget("Shaders" ${fname}.spv)
         add_dependencies(vulkan_grass_rendering ${fname}.spv)
+    else(WIN32)
+        get_filename_component(fname ${SHADER_SOURCE} NAME)
+        set(SHADER_OUTPUT ${SHADER_DIR}/${fname}.spv)
+
+        add_custom_command(
+            OUTPUT ${SHADER_OUTPUT}
+            COMMAND ${CMAKE_COMMAND} -E make_directory ${SHADER_DIR}
+            COMMAND glslc ${SHADER_SOURCE} -o ${SHADER_OUTPUT}
+            DEPENDS ${SHADER_SOURCE}
+            COMMENT "Compiling ${fname} to SPIR-V"
+        )
+
+        list(APPEND COMPILED_SHADERS ${SHADER_OUTPUT})
     endif(WIN32)
 
-    # TODO: Build shaders on not windows
 endforeach()
 
+add_custom_target(compile_shaders DEPENDS ${COMPILED_SHADERS})
+add_dependencies(vulkan_grass_rendering compile_shaders)
+
 target_link_libraries(vulkan_grass_rendering ${ASSIMP_LIBRARIES} Vulkan::Vulkan glfw)
 target_include_directories(vulkan_grass_rendering PRIVATE
   ${CMAKE_CURRENT_SOURCE_DIR}

src/Device.h

@@ -6,6 +6,7 @@
 #include "QueueFlags.h"
 #include "SwapChain.h"
 
+class Instance;
 class SwapChain;
 class Device {
     friend class Instance;