Add README

- Also, make OpenMP optional via a CMake flag

.gitignore

@@ -79,3 +79,6 @@ fabric.properties
 
 
 # End of https://www.gitignore.io/api/Jetbrains
+
+# Folder for building
+build/**

CMakeLists.txt

@@ -7,7 +7,7 @@ if(CCACHE_FOUND)
     set_property(GLOBAL PROPERTY RULE_LAUNCH_LINK ccache)
 endif(CCACHE_FOUND)
 
-set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD 14)
 set(CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake)
 
 set(ALTLIB_DIR ${PROJECT_SOURCE_DIR}/deps/altlib)

README.md

@@ -0,0 +1,99 @@
+# Eulerian Fluid Simulation
+
+This is a (work in progress) fluid simulation library based on the methods in the book *Fluid Simulation for Computer Graphics* by Robert Bridson (2nd edition). 
+
+It implements the following methods:
+
+- Semi-Lagrangian Method
+- PIC/FLIP Method (Interpolate between PIC and FLIP)
+
+Only 2D version is implemented as of now. (I want to make sure the 2D version works perfectly before moving on to 3D.)
+
+Features that really need to be implemented as of now:
+
+- Particle reseeding
+- Volume correction
+
+Right now, the fluid simulation doesn't conserve volume very well, so these two will help in remedying this.
+
+Features that might be implemented later on (if I have the time):
+
+- Fluid rendering via Marching Cube method
+- APIC (Affine Particle-in-Cell) method
+- Support for solids not fixed on the grid
+- Support for moving solids
+- 3D simulation
+
+# Requirements
+
+- Compiler with C++14 support
+- CPU with AVX/FMA support (As of now this is mandatory, because I've used some AVX/FMA intrinsics in code. Also, the math library I am using requires this too. Later on I would loosen up the requirements.)
+
+These are the platforms I've tested on:
+
+- Windows (MinGW, clang)
+- Linux (Arch Linux, gcc or clang)
+
+Note that if you're on Windows MinGW, you shouldn't use GCC because it has bugs with AVX/AVX2 instruction generation! (For a more detailed description, check the following issue: https://github.com/Alexpux/MSYS2-packages/issues/1209).
+
+Optionally, you can enable OpenMP via the ``USE_OPENMP`` CMake option. (However, it doesn't work on MinGW clang for some unknown reasons)
+
+# Running the demo
+
+Linux (GCC or Clang)
+
+```sh
+git clone --recursive https://github.com/lasagnaphil/fluid-sim
+mkdir build && cd build
+cmake .. -DCMAKE_BUILD_TYPE=Release
+make
+demo/fluid_sim_demo
+```
+
+Windows (in MinGW-w64 shell)
+```sh
+git clone --recursive https://github.com/lasagnaphil/fluid-sim
+mkdir build && cd build
+cmake .. -G "MinGW Makefiles" -DCMAKE_BUILD_TYPE=Release
+mingw32-make
+demo/fluid_sim_demo.exe
+```
+
+# Dependencies
+
+For the library:
+
+- [altlib](https://github.com/lasagnaphil/altlib): Alternative C++ Library
+- [altmath](https://github.com/lasagnaphil/altmath): Alternative Math Library
+
+These two are in the source code as git submodules. Make sure you clone them too! (using the ``--recursive`` flag)
+
+For the demo:
+
+- [glad](https://github.com/Dav1dde/glad): OpenGL function loader generator
+- [imgui](https://github.com/ocornut/imgui): Dear ImGui
+- [stb_image](https://github.com/nothings/stb): Image loading
+
+# License
+
+MIT License
+
+Copyright (c) 2019 Philsik Chang
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

src/CMakeLists.txt

@@ -28,11 +28,14 @@ find_package(Threads REQUIRED)
 target_link_libraries(fluid_sim PRIVATE Threads::Threads)
 
 # OpenMP
-find_package(OpenMP)
-if (OpenMP_FOUND)
-    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${OpenMP_C_FLAGS}")
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OpenMP_CXX_FLAGS}")
-    set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} ${OpenMP_SHARED_LINKER_FLAGS}")
-    set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} ${OpenMP_EXE_LINKER_FLAGS}")
+option(USE_OPENMP "Use OpenMP." OFF)
+if (USE_OPENMP)
+    find_package(OpenMP)
+    if (OpenMP_FOUND)
+        set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${OpenMP_C_FLAGS}")
+        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OpenMP_CXX_FLAGS}")
+        set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} ${OpenMP_SHARED_LINKER_FLAGS}")
+        set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} ${OpenMP_EXE_LINKER_FLAGS}")
+    endif()
 endif()