First work on the fluid simulation

Apps/GreenWorld/GreenWorldInterface.cpp

@@ -130,10 +130,10 @@ namespace GW
 
     void GreenWorldInterface::InitUI()
     {
+        _windowAlphaValue = 0.65;
         LoadCustomFont("../Res/Assets/Fonts/JetBrainsMono-Medium.ttf", 19);
         SetDarkThemeColors();
         CalcElementSizes();
-        _windowAlphaValue = 0.65;
     }
 
     void GreenWorldInterface::AddElements()

Apps/Liquefied/LiquefiedApp.cpp

@@ -10,7 +10,7 @@ namespace Liq
         Engine::ResourceManager::LoadShader("SpriteShader", "../Res/Shader/GreenWorld/Sprite_VS.glsl", "../Res/Shader/GreenWorld/Sprite_FS.glsl");
 
         //Texture
-        Engine::ResourceManager::LoadTextureToBuffer("BG_Texture", "../Res/Assets/Textures/Liquefied/Dark_Squares.jpg");
+        Engine::ResourceManager::LoadTextureToBuffer("BG_Texture", "../Res/Assets/Textures/Liquefied/Dark_Squares_1500.jpg");
     }
 
     Engine::uint32 LiquefiedApp::InitModules()
@@ -32,9 +32,23 @@ namespace Liq
         //Create UI
         _interface = Engine::MakeScope<LiquefiedInterface>();
 
+        //Create fluid simulator
+        _fluidSimulator = Engine::MakeScope<Engine::FluidSimulator>();
+
         return EXIT_SUCCESS;
     }
 
+    void LiquefiedApp::VisualizeSmoke()
+    {
+        float* smokeField = _fluidSimulator->GetSmokeField();
+
+        //Iterate over smoke field
+
+        //Set color at pixel(x,y) to the value of the vector field at (x,y)
+
+        //Using scientific color scheme
+    }
+
     // ----- Public -----
 
     LiquefiedApp::LiquefiedApp()
@@ -73,6 +87,13 @@ namespace Liq
             Engine::RenderManager::PrepareFrame();
         }
 
+        {
+            Engine::PROFILE_SCOPE("Simulate liquid");
+
+            _fluidSimulator->TimeStep();
+            VisualizeSmoke();
+        }
+
         {
             Engine::PROFILE_SCOPE("Render pixels");
 

Apps/Liquefied/LiquefiedApp.hpp

@@ -8,11 +8,13 @@ namespace Liq
     class LiquefiedApp final : public Engine::App
     {
         private:
-            Engine::PixelRenderer*            _pixelRenderer = nullptr;
-            Engine::Scope<LiquefiedInterface> _interface;
+            Engine::PixelRenderer*                _pixelRenderer = nullptr;
+            Engine::Scope<LiquefiedInterface>     _interface;
+            Engine::Scope<Engine::FluidSimulator> _fluidSimulator;
 
             void           LoadResources() override;
             Engine::uint32 InitModules()   override;
+            void           VisualizeSmoke();
 
         public:
             LiquefiedApp();

Apps/Liquefied/LiquefiedInterface.cpp

@@ -13,12 +13,6 @@ namespace Liq
                 ImGui::MenuItem("Show overlay", "", &Engine::UIParams::showOverlay);
                 ImGui::EndMenu();
             }
-
-            if(ImGui::BeginMenu("Rendering"))
-            {
-                ImGui::MenuItem("Wireframe-Mode", "", &Engine::UIParams::wireframeRendering);
-                ImGui::EndMenu();
-            }
         }
         ImGui::EndMainMenuBar();
     }
@@ -50,6 +44,19 @@ namespace Liq
         ImGui::End();
     }
 
+    void LiquefiedInterface::AddBufferBar() const
+    {
+        ImGui::SetNextWindowBgAlpha(0.9f);
+        ImGui::SetNextWindowPos(_bufferBarPos, ImGuiCond_Always);
+        ImGui::SetNextWindowSize(_bufferBarSize);
+
+        if(ImGui::Begin("Bufferbar", nullptr, _windowFlags))
+        {
+            // ...
+        }
+        ImGui::End();
+    }
+
     // ----- Public -----
 
     LiquefiedInterface::LiquefiedInterface()
@@ -67,7 +74,7 @@ namespace Liq
 
     void LiquefiedInterface::AddElements()
     {
-        ImGui::PushStyleVar(ImGuiStyleVar_WindowBorderSize, 0.0f);
+        ImGui::PushStyleVar(ImGuiStyleVar_WindowBorderSize, 1.0f);
 
         //Discard old plotting data every 120 frames
         if(Engine::Window::GetFrameCounter() > 120)
@@ -76,6 +83,7 @@ namespace Liq
         }
 
         AddMenuBar();
+        AddBufferBar();
 
         if(Engine::UIParams::showOverlay)
         {

Apps/Liquefied/LiquefiedInterface.hpp

@@ -7,8 +7,12 @@ namespace Liq
     class LiquefiedInterface final : public Engine::Interface
     {
         private:
+            ImVec2 _bufferBarSize = ImVec2((float)Engine::WindowParams::WIDTH - _sidebarWidth, 80.0f - _menuBarHeight);
+            ImVec2 _bufferBarPos  = ImVec2(0.0f, _menuBarHeight);
+
             void AddMenuBar() const;
             void AddSideBar() const;
+            void AddBufferBar() const;
 
         public:
             LiquefiedInterface();

CMakeLists.txt

@@ -27,6 +27,7 @@ target_include_directories(SalinityGL PUBLIC Engine/Application)
 target_include_directories(SalinityGL PUBLIC Engine/Core)
 target_include_directories(SalinityGL PUBLIC Engine/Debug)
 target_include_directories(SalinityGL PUBLIC Engine/Physics/CellularAutomata)
+target_include_directories(SalinityGL PUBLIC Engine/Physics/FluidSimulation)
 target_include_directories(SalinityGL PUBLIC Engine/Rendering/Buffers)
 target_include_directories(SalinityGL PUBLIC Engine/Rendering/Camera)
 target_include_directories(SalinityGL PUBLIC Engine/Rendering/Renderables)

Engine/Application/GlobalParams.hpp

@@ -84,12 +84,6 @@ namespace Engine
         }
     };
 
-    #define COLOR_WHITE glm::vec3(1.0f, 1.0f, 1.0f)
-    #define COLOR_BLACK glm::vec3(1.0f, 1.0f, 1.0f)
-    #define COLOR_RED   glm::vec3(1.0f, 0.0f, 0.0f)
-    #define COLOR_GREEN glm::vec3(0.0f, 1.0f, 0.0f)
-    #define COLOR_BLUE  glm::vec3(0.0f, 0.0f, 1.0f)
-
     // #######################################################################################################
     // ############################################### GreenWorld ############################################
     // #######################################################################################################
@@ -152,5 +146,10 @@ namespace Engine
     // ############################################### Liquefied #############################################
     // #######################################################################################################
 
-    //Nothing here
+    struct LiquiefiedParams
+    {
+        inline static constexpr uint32 SIMULATION_WIDTH  = 1500;
+        inline static constexpr uint32 SIMULATION_HEIGHT = 1000;
+        inline static constexpr uint32 LIQUID_NUM_CELLS  = SIMULATION_WIDTH * SIMULATION_HEIGHT;
+    };
 }

Engine/Core/Types.hpp

@@ -33,4 +33,10 @@ namespace Engine
     typedef uint16_t uint16;
     typedef uint32_t uint32;
     typedef uint64_t uint64;
+
+    #define COLOR_WHITE glm::vec3(1.0f, 1.0f, 1.0f)
+    #define COLOR_BLACK glm::vec3(1.0f, 1.0f, 1.0f)
+    #define COLOR_RED   glm::vec3(1.0f, 0.0f, 0.0f)
+    #define COLOR_GREEN glm::vec3(0.0f, 1.0f, 0.0f)
+    #define COLOR_BLUE  glm::vec3(0.0f, 0.0f, 1.0f)
 }

Engine/Core/Utility.cpp

@@ -0,0 +1,28 @@
+#include "Utility.hpp"
+
+namespace Engine
+{
+    // ----- Public -----
+
+    glm::vec3 Utility::GetScienticColor(float value, const float min, const float max)
+    {
+        value = fminf(fmaxf(value, min), max - 0.0001f);
+        const float diff = max - min;
+        value = diff == 0.0f ? 0.5f : (value - min) / diff;
+        const float divider = 0.25f;
+        const float number  = floorf(value / divider);
+        const float pos     = (value - number * divider) / divider;
+
+        glm::vec3 retVec{0.0f};
+        switch(number)
+        {
+            case 0 : retVec.x = 0.0f; retVec.y = pos;  retVec.z = 1.0f;       break;
+            case 1 : retVec.x = 0.0f; retVec.y = 1.0f; retVec.z = 1.0f - pos; break;
+            case 2 : retVec.x = pos;  retVec.y = 1.0f; retVec.z = 0.0f;       break;
+            case 3 : retVec.x = 1.0f; retVec.y = 1.0f; retVec.z = 0.0f;       break;
+            default: break;
+        }
+
+        return retVec;
+    }
+}

Engine/Core/Utility.hpp

@@ -0,0 +1,15 @@
+#pragma once
+
+#include "glm.hpp"
+
+#include <cmath>
+
+namespace Engine
+{
+    class Utility
+    {
+        public:
+            Utility() = delete;
+            static glm::vec3 GetScienticColor(float value, float min, float max);
+    };
+}

Engine/Engine.hpp

@@ -26,4 +26,7 @@
 #include "SpriteRenderer.hpp"
 #include "WaterRenderer.hpp"
 #include "ParticleRenderer.hpp"
-#include "CellManager.hpp"
+
+// ----- Physics -----
+#include "CellManager.hpp"
+#include "FluidSimulator.hpp"

Engine/Physics/FluidSimulation/FluidSimulator.cpp

@@ -0,0 +1,58 @@
+#include "FluidSimulator.hpp"
+
+namespace Engine
+{
+    // ----- Private -----
+
+    /* Applies forces to the liquid - just gravity in our case */
+    void FluidSimulator::AddForces(float dt)
+    {
+
+    }
+
+    /* Projection calculates and applies the right amount of pressure to make the       *
+     * velocity field divergence-free and also enforces solid wall boundary conditions. */
+    void FluidSimulator::Project(float dt)
+    {
+
+    }
+
+    /* Advection moves the quantity, or molecules, or particles, along the velocity field. */
+    void FluidSimulator::AdvectVelocity(float dt)
+    {
+
+    }
+
+    /* To visualize the flow, we store a density or dye value at the center of each cell  *
+     * and advect it like the velocity field.                                             */
+    void FluidSimulator::AdvectSmoke(float dt)
+    {
+
+    }
+
+    // ----- Public -----
+
+    FluidSimulator::FluidSimulator()
+    {
+
+    }
+
+    FluidSimulator::~FluidSimulator()
+    {
+
+    }
+
+    void FluidSimulator::TimeStep()
+    {
+        float dt = (float)Window::GetDeltaTime();
+        AddForces(dt);
+        Project(dt);
+        AdvectVelocity(dt);
+        AdvectSmoke(dt);
+    }
+
+    float* FluidSimulator::GetSmokeField()
+    {
+        return &_smokeField[0];
+    }
+}

Engine/Physics/FluidSimulation/FluidSimulator.hpp

@@ -0,0 +1,28 @@
+#pragma once
+
+#include "Window.hpp"
+#include "GlobalParams.hpp"
+
+#define at(x, y) ((x) * Liquiedfied::Params::SIMULATION_HEIGHT + (y))
+
+namespace Engine
+{
+    class FluidSimulator
+    {
+        private:
+            float _gravity = -9.81f;
+            float _velocityField[LiquiefiedParams::LIQUID_NUM_CELLS] = {0};
+            float _smokeField[LiquiefiedParams::LIQUID_NUM_CELLS]    = {0};
+
+            void AddForces(float dt);
+            void Project(float dt);
+            void AdvectVelocity(float dt);
+            void AdvectSmoke(float dt);
+
+        public:
+            FluidSimulator();
+            ~FluidSimulator();
+            void TimeStep();
+            float* GetSmokeField();
+    };
+}

Engine/Rendering/Resources/Texture.cpp

@@ -203,7 +203,7 @@ namespace Engine
     void Texture::CommitModifications() const
     {
         Bind();
-        GLCall(glTexImage2D(GL_TEXTURE_2D, 0, _format, _width, _height, 0, _format, GL_UNSIGNED_BYTE, _imgBuffer));
+        GLCall(glTexSubImage2D (GL_TEXTURE_2D, 0, 0, 0, _width, _height, GL_RGB, GL_UNSIGNED_BYTE, _imgBuffer));
         Unbind();
     }