增加重力系统

first_app.cpp

@@ -1,5 +1,7 @@
 #include "first_app.hpp"
 #include "simple_render_system.hpp"
+#include "rainbow_system.hpp"
+#include "gravity_physics_system.hpp"
 
 // libs
 #define GLM_FORCE_RADIANS
@@ -11,6 +13,7 @@
 #include <stdexcept>
 #include <array>
 
+
 namespace hk
 {
     FirstApp::FirstApp()
@@ -22,13 +25,84 @@ namespace hk
     {
     }
 
+    void FirstApp::runGravitySystem()
+    {
+        // Gravity Physics System 
+        // Create some Models
+        std::shared_ptr<Model> squareModel = createSquareModel(m_device, {.5f, .0f});
+        std::shared_ptr<Model> circleModel = createCircleModel(m_device, 64);
+        // Create Physics Objects
+        std::vector<GameObject> physicsObjects{};
+        auto red = GameObject::createGameObject();
+        red.m_transform2d.scale = glm::vec2{.05f};
+        red.m_transform2d.translation = {.5f, .5f};
+        red.m_color = {1.f, 0.f, 0.f};
+        red.m_rigidBody2d.velocity = {-.5f, .0f};
+        red.m_model = circleModel;
+        physicsObjects.push_back(std::move(red));
+        auto blue = GameObject::createGameObject();
+        blue.m_transform2d.scale = glm::vec2{.05f};
+        blue.m_transform2d.translation = {-.45f, -.25f};
+        blue.m_color = {0.f, 0.f, 1.f};
+        blue.m_rigidBody2d.velocity = {.5f, .0f};
+        blue.m_model = circleModel;
+        physicsObjects.push_back(std::move(blue));
+
+        // Create Vector Field 
+        std::vector<GameObject> vectorField{};
+        int gridCount = 40;
+        for (int i = 0; i < gridCount; i++)
+        {
+            for(int j = 0; j < gridCount; j ++)
+            {
+                auto vf = GameObject::createGameObject();
+                vf.m_transform2d.scale = glm::vec2{0.005f};
+                vf.m_transform2d.translation = {-1.0f + (i + 0.5f) * 2.0f / gridCount, -1.0f + (j + 0.5f) * 2.0f / gridCount};
+                vf.m_color = glm::vec3{1.0f};
+                vf.m_model = squareModel;
+                vectorField.push_back(std::move(vf));
+            }
+        }
+
+        GravityPhysicsSystem gravitySystem(0.81f);
+        Vec2FieldSystem vecFieldSystem{};
+
+        SimpleRenderSystem simpleRenderSystem{m_device, m_renderer.getSwapChainRenderPass()};
+
+        while(!m_window.shouldClose())
+        {
+            glfwPollEvents();
+
+            if (auto commandBuffer = m_renderer.beginFrame())
+            {
+                // update system
+                gravitySystem.update(physicsObjects, 1.f / 60, 5);
+                vecFieldSystem.update(gravitySystem, physicsObjects, vectorField);
+
+                // render system
+                m_renderer.beginSwapChainRenderPass(commandBuffer);
+                simpleRenderSystem.renderGameObjects(commandBuffer, physicsObjects);
+                simpleRenderSystem.renderGameObjects(commandBuffer, vectorField);
+                m_renderer.endSwapChainRenderPass(commandBuffer);
+                m_renderer.endFrame();
+            }
+
+            vkDeviceWaitIdle(m_device.device());
+        }
+    }
+
     void FirstApp::run()
     {
         SimpleRenderSystem simpleRenderSystem{m_device, m_renderer.getSwapChainRenderPass()};
+        RainbowSystem rainbowSystem(2000.0f);
+
         while (!m_window.shouldClose())
         {
             glfwPollEvents();
             
+            // update objects color
+            rainbowSystem.update(5.0f, m_gameObjects);
+
             if (auto commandBuffer = m_renderer.beginFrame())
             {
                 m_renderer.beginSwapChainRenderPass(commandBuffer);

first_app.hpp

@@ -24,6 +24,7 @@ namespace hk
         FirstApp &operator=(const FirstApp &) = delete;
 
         void run();
+        void runGravitySystem();
 
     private:
         void loadGameObjects();

gravity_physics_system.hpp

@@ -0,0 +1,129 @@
+#pragma once
+
+#include <hk_game_object.hpp>
+
+#define GLM_FORCE_RADIANS
+#define GLM_FORCE_DEPTH_ZERO_TO_ONE
+#include <glm/glm.hpp>
+#include <glm/gtc/constants.hpp>
+
+// std
+#include <memory>
+#include <random>
+#include <vector>
+
+namespace hk
+{
+    class GravityPhysicsSystem
+    {
+    public:
+        GravityPhysicsSystem(float strength) :m_strengthGravity(strength) {}
+
+        void update(std::vector<GameObject> &objs, float dt, unsigned int substeps = 1)
+        {
+            const float stepDelta = dt / substeps;
+
+            for (int i = 0; i < substeps; i++)
+            {
+                stepSimulation(objs, stepDelta);
+            }
+        }
+
+        glm::vec2 computeForce(GameObject &fromObj, GameObject &toObj) const 
+        {
+            auto offset = fromObj.m_transform2d.translation - toObj.m_transform2d.translation;
+            float distanceSquared = glm::dot(offset, offset);
+
+            if (glm::abs(distanceSquared < 1e-10f))
+            {
+                return {.0f, .0f};
+            }
+            float force = m_strengthGravity * toObj.m_rigidBody2d.mass * fromObj.m_rigidBody2d.mass / distanceSquared;
+
+            return force * offset / glm::sqrt(distanceSquared);
+        }
+
+        const float m_strengthGravity;
+    private:
+        void stepSimulation(std::vector<GameObject> &physicsObjs, float dt)
+        {
+            // Loops throught all pairs of objects and applies attractive force between them
+            for (auto iterA = physicsObjs.begin(); iterA != physicsObjs.end(); ++iterA)
+            {
+                auto &objA = *iterA;
+                for (auto iterB = iterA; iterB != physicsObjs.end(); ++iterB)
+                {
+                    if (iterA == iterB) continue;
+
+                    auto &objB = *iterB;
+                    auto force = computeForce(objA, objB);
+                    objA.m_rigidBody2d.velocity += dt * -force / objA.m_rigidBody2d.mass;
+                    objB.m_rigidBody2d.velocity += dt * force / objB.m_rigidBody2d.mass;
+                }
+            }
+
+            // update each objects position based on its final velocity
+            for (auto &obj : physicsObjs)
+            {
+                obj.m_transform2d.translation += dt * obj.m_rigidBody2d.velocity;
+            }
+        }
+    };
+
+    class Vec2FieldSystem
+    {
+    public:
+        void update(const GravityPhysicsSystem &physicsSystem, std::vector<GameObject> &physicsObjs, std::vector<GameObject> &vectorField)
+        {
+            for (auto &vf : vectorField)
+            {
+                glm::vec2 direction{};
+                for (auto &obj : physicsObjs)
+                {
+                    direction += physicsSystem.computeForce(obj, vf);
+                }
+
+                vf.m_transform2d.scale.x = 0.005f + 0.045f * glm::clamp(glm::log(glm::length(direction) + 1) / 3.f, 0.f, 1.f);
+                vf.m_transform2d.rotation = atan2(direction.y, direction.x);
+            }
+        }
+    };
+
+    std::unique_ptr<Model> createSquareModel(Device &device, glm::vec2 offset)
+    {
+        std::vector<Model::Vertex> vertices = {
+            {{-0.5f, -0.5f}}, {{0.5f, 0.5f}},
+            {{-0.5f, 0.5f}}, {{-0.5f, -0.5f}},
+            {{0.5f, -0.5f}}, {{0.5f, 0.5f}},
+        };
+
+        for (auto &v : vertices)
+        {
+            v.posision += offset;
+        }
+
+        return std::make_unique<Model>(device, vertices);
+    }
+
+    std::unique_ptr<Model> createCircleModel(Device &device, unsigned int numSides)
+    {
+        std::vector<Model::Vertex> uniqueVertices{};
+        for(int i = 0; i < numSides; i++)
+        {
+            float angle = i * glm::two_pi<float>() / numSides;
+            uniqueVertices.push_back({{glm::cos(angle), glm::sin(angle)}});
+        }
+
+        uniqueVertices.push_back({});
+
+        std::vector<Model::Vertex> vertices{};
+        for(int i = 0; i < numSides; i++)
+        {
+            vertices.push_back(uniqueVertices[i]);
+            vertices.push_back(uniqueVertices[(i+1) % numSides]);
+            vertices.push_back(uniqueVertices[numSides]);
+        }
+        return std::make_unique<Model>(device, vertices);
+    }
+
+}

hk_game_object.hpp

@@ -28,6 +28,12 @@ namespace hk
         }
     };
 
+    struct RigidBody2dComponent
+    {
+        glm::vec2 velocity;
+        float mass{1.0f};
+    };
+
     class GameObject
     {
     public:
@@ -51,6 +57,8 @@ namespace hk
         glm::vec3 m_color{};
         Transform2dComponent m_transform2d{}; 
 
+        RigidBody2dComponent m_rigidBody2d{};
+
     private:
         GameObject(id_t objId) : m_id(objId) {}
 

hk_swap_chain.cpp

@@ -423,14 +423,14 @@ namespace hk
   VkPresentModeKHR SwapChain::chooseSwapPresentMode(
       const std::vector<VkPresentModeKHR> &availablePresentModes)
   {
-    // for (const auto &availablePresentMode : availablePresentModes)
-    // {
-    //   if (availablePresentMode == VK_PRESENT_MODE_MAILBOX_KHR)
-    //   {
-    //     std::cout << "Present mode: Mailbox" << std::endl;
-    //     return availablePresentMode;
-    //   }
-    // }
+    for (const auto &availablePresentMode : availablePresentModes)
+    {
+      if (availablePresentMode == VK_PRESENT_MODE_MAILBOX_KHR)
+      {
+        std::cout << "Present mode: Mailbox" << std::endl;
+        return availablePresentMode;
+      }
+    }
 
     // for (const auto &availablePresentMode : availablePresentModes)
     // {

main.cpp

@@ -5,13 +5,19 @@
 #include <iostream>
 #include <stdexcept>
 
+#define GRAVITY_SYSTEM 1
+
 int main()
 {
     hk::FirstApp app{};
 
     try
     {
+#if GRAVITY_SYSTEM == 1
+        app.runGravitySystem();
+#else
         app.run();
+#endif
     }
     catch(const std::exception& e)
     {

rainbow_system.hpp

@@ -0,0 +1,44 @@
+#pragma once
+
+#include <hk_game_object.hpp>
+
+// std
+#include <memory>
+#include <random>
+#include <vector>
+
+namespace hk
+{
+    class RainbowSystem
+    {
+    public:
+        RainbowSystem(float flickerRate) : m_flickerRate(flickerRate)
+        {
+            // initialize colors
+            m_color = {{.8f, .1f, .1f}, {.1f, .8f, .1f}, {.1f, .1f, .8f}, {.8f, .8f, .1f}, {.8f, .1f, .8f}, {.1f, .8f, .8f}};
+            m_elapsedTime = m_flickerRate;
+        }
+
+        void update(float dt, std::vector<GameObject> &gameObjects)
+        {
+            m_elapsedTime -= dt;
+            if (m_elapsedTime < 0.f)
+            {
+                std::uniform_int_distribution<int> randInt{0, static_cast<int>(m_color.size()) -1};
+                for (auto &obj : gameObjects)
+                {
+                    int randValue = randInt(m_rng);
+                    obj.m_color = m_color[randValue];
+                }
+            }
+        }
+
+    private:
+        std::random_device m_rd;
+        std::mt19937 m_rng{m_rd()};
+
+        std::vector<glm::vec3> m_color;
+        float m_flickerRate;
+        float m_elapsedTime;
+    };
+}