Project 5: RICHARD CHEN

.gitignore

@@ -0,0 +1,5 @@
+bin/*
+build/*
+bin/Release/vulkan_grass_rendering.exe
+bin/*
+*.exe

README.md

@@ -3,10 +3,59 @@ Vulkan Grass Rendering
 
 **University of Pennsylvania, CIS 565: GPU Programming and Architecture, Project 5**
 
-* (TODO) YOUR NAME HERE
-* Tested on: (TODO) Windows 22, i7-2222 @ 2.22GHz 22GB, GTX 222 222MB (Moore 2222 Lab)
+* Richard Chen
+* Tested on: Windows 11, i7-10875H @ 2.3GHz 16GB, RTX 2060 MAX-Q 6GB (PC)
 
-### (TODO: Your README)
+![](img/vulkan_grass_gif.gif)
 
-*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.
+## Overview
+
+Unlike the ubiquitous OpenGL, Vulkan is a low level graphics API that gives much
+more control to the programmer (at the cost of being incredibly verbose). 
+This comes with the added benefit of having a much higher performance ceiling
+and low level graphics APIs like Vulkan, Metal, and DirectX 12 being used by 
+game engines and where performance is needed.
+
+In this project, we implemented a grass simulation based on "Responsive 
+Real-Time Grass Rendering for General 3D Scenes" by Jahrmann and Wimmer in 
+Vulkan. We used compute shaders to do physics calculations like wind, gravity, 
+and restoring force. Additionally, tessellation shaders were added to the usual 
+graphics pipeline of vertex and fragment shaders, where fixed function dedicated
+hardware allows for fast and efficient tessellation of scenes.
+
+## Features
+
+### Grass
+The blades of grass were modelled as Bezier curves. Each blade had v0, v1, and v2 
+as the control points and an up vector, and orientation, height, width, and 
+stiffness as scalar parameters. All of the parameters fit nicely into 4 vec4s.   
+![](img/blade_model.jpg)
+
+### Physics
+As an approximation, the forces of gravity, wind, and a restoring force were
+scaled by the time step and applied to the tip of the grass blade. Then, 
+corrections were added to 
+ensure the resulting position was valid, 
+calculate v1 from v2, 
+and maintain that grass blade lengths were invariant.
+![](img/thick_grass.png)
+
+### Optimizations
+
+* Orientation Culling: Grass blades can be approximated as a 2D plane so they
+are not rendered when viewed edge-on 
+
+* Distance Culling: When farther away, less grass is rendered until none are 
+rendered at all
+
+* View Frustrum Culling: Blades that the outside the camera's field of view are
+not rendered as there is no point to doing computations on objects that will 
+not be seen
+
+### Other
+* Lambertian Shading, where the color intensity is scaled by how directly the 
+surface faces the camera
+
+Lambert | Flat
+--------|------
+![](img/lambert.png) | ![](img/flat.png)

src/Blades.cpp

@@ -2,15 +2,18 @@
 #include "Blades.h"
 #include "BufferUtils.h"
 
-float generateRandomFloat() {
+float generateRandomFloat()
+{
     return rand() / (float)RAND_MAX;
 }
 
-Blades::Blades(Device* device, VkCommandPool commandPool, float planeDim) : Model(device, commandPool, {}, {}) {
+Blades::Blades(Device *device, VkCommandPool commandPool, float planeDim) : Model(device, commandPool, {}, {})
+{
     std::vector<Blade> blades;
     blades.reserve(NUM_BLADES);
 
-    for (int i = 0; i < NUM_BLADES; i++) {
+    for (int i = 0; i < NUM_BLADES; i++)
+    {
         Blade currentBlade = Blade();
 
         glm::vec3 bladeUp(0.0f, 1.0f, 0.0f);
@@ -45,23 +48,27 @@ 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_VERTEX_BUFFER_BIT | VK_BUFFER_USAGE_STORAGE_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);
 }
 
-VkBuffer Blades::GetBladesBuffer() const {
+VkBuffer Blades::GetBladesBuffer() const
+{
     return bladesBuffer;
 }
 
-VkBuffer Blades::GetCulledBladesBuffer() const {
+VkBuffer Blades::GetCulledBladesBuffer() const
+{
     return culledBladesBuffer;
 }
 
-VkBuffer Blades::GetNumBladesBuffer() const {
+VkBuffer Blades::GetNumBladesBuffer() const
+{
     return numBladesBuffer;
 }
 
-Blades::~Blades() {
+Blades::~Blades()
+{
     vkDestroyBuffer(device->GetVkDevice(), bladesBuffer, nullptr);
     vkFreeMemory(device->GetVkDevice(), bladesBufferMemory, nullptr);
     vkDestroyBuffer(device->GetVkDevice(), culledBladesBuffer, nullptr);

src/Blades.h

@@ -4,15 +4,16 @@
 #include <array>
 #include "Model.h"
 
-constexpr static unsigned int NUM_BLADES = 1 << 13;
+constexpr static unsigned int NUM_BLADES = 1 << 14;
 constexpr static float MIN_HEIGHT = 1.3f;
 constexpr static float MAX_HEIGHT = 2.5f;
 constexpr static float MIN_WIDTH = 0.1f;
 constexpr static float MAX_WIDTH = 0.14f;
 constexpr static float MIN_BEND = 7.0f;
 constexpr static float MAX_BEND = 13.0f;
 
-struct Blade {
+struct Blade
+{
     // Position and direction
     glm::vec4 v0;
     // Bezier point and height
@@ -22,7 +23,8 @@ struct Blade {
     // Up vector and stiffness coefficient
     glm::vec4 up;
 
-    static VkVertexInputBindingDescription getBindingDescription() {
+    static VkVertexInputBindingDescription getBindingDescription()
+    {
         VkVertexInputBindingDescription bindingDescription = {};
         bindingDescription.binding = 0;
         bindingDescription.stride = sizeof(Blade);
@@ -31,7 +33,8 @@ struct Blade {
         return bindingDescription;
     }
 
-    static std::array<VkVertexInputAttributeDescription, 4> getAttributeDescriptions() {
+    static std::array<VkVertexInputAttributeDescription, 4> getAttributeDescriptions()
+    {
         std::array<VkVertexInputAttributeDescription, 4> attributeDescriptions = {};
 
         // v0
@@ -62,14 +65,16 @@ struct Blade {
     }
 };
 
-struct BladeDrawIndirect {
+struct BladeDrawIndirect
+{
     uint32_t vertexCount;
     uint32_t instanceCount;
     uint32_t firstVertex;
     uint32_t firstInstance;
 };
 
-class Blades : public Model {
+class Blades : public Model
+{
 private:
     VkBuffer bladesBuffer;
     VkBuffer culledBladesBuffer;
@@ -80,7 +85,7 @@ class Blades : public Model {
     VkDeviceMemory numBladesBufferMemory;
 
 public:
-    Blades(Device* device, VkCommandPool commandPool, float planeDim);
+    Blades(Device *device, VkCommandPool commandPool, float planeDim);
     VkBuffer GetBladesBuffer() const;
     VkBuffer GetCulledBladesBuffer() const;
     VkBuffer GetNumBladesBuffer() const;