Make python3 default for Mantaflow and update README.md with build and test instruction

CMakeLists.txt

@@ -10,8 +10,8 @@
 #
 #******************************************************************************
 
+cmake_minimum_required(VERSION 3.5)
 project (MantaFlow)
-cmake_minimum_required(VERSION 2.8)
 
 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_SOURCE_DIR}/tools/cmake/")
 set(CMAKE_ALLOW_LOOSE_LOOP_CONSTRUCTS true)
@@ -117,15 +117,11 @@ endif()
 
 # translate option into python version string
 if(NOT PYTHON_VERSION)
-  set(PYTHON_VER_ID) # use any...
+  set(PYTHON_VER_ID 3) # use version 3
 else()
   set(PYTHON_VER_ID ${PYTHON_VERSION})
 endif()
 
-if(OPENVDB AND NOT TBB)
-	message(FATAL_ERROR "Cannot activate OPENVDB without TBB")
-endif()
-
 MESSAGE(STATUS "")
 MESSAGE(STATUS "Options - "
 	" -DDEBUG='${DEBUG}' "
@@ -387,7 +383,7 @@ if(OPENVDB)
 		else()
 			message("Warning - OpenVDB not found, trying default paths") 
 			# might be in path...
-			list(APPEND F_LIBS Half openvdb tbb)
+			list(APPEND F_LIBS Imath openvdb tbb)
 		endif()
 	endif()
 
@@ -399,7 +395,7 @@ if(OPENVDB)
 			list(APPEND INCLUDE_PATHS ${HOUDINI_INCLUDE_DIRS})
 			list(APPEND INCLUDE_PATHS ${HOUDINI_INCLUDE_DIRS}/OpenEXR)
 			list(APPEND F_LIB_PATHS ${HOUDINI_LIBRARY_DIRS})
-			list(APPEND F_LIBS "Half.lib")
+			list(APPEND F_LIBS "Imath.lib")
 		endif()
 	else()
 		# for open exr - should be in the default path, add includes if necessary

README.md

@@ -1,7 +1,7 @@
 # Mantaflow #
 
 Mantaflow is an open-source framework targeted at fluid simulation research in Computer Graphics.
-Its parallelized C++ solver core, python scene definition interface and plugin system allow for quickly prototyping and testing new algorithms. 
+Its parallelized C++ solver core, python scene definition interface and plugin system allow for quickly prototyping and testing new algorithms.
 
 In addition, it provides a toolbox of examples for deep learning experiments with fluids. E.g., it contains examples
 how to build convolutional neural network setups in conjunction with the [tensorflow framework](https://www.tensorflow.org).
@@ -11,3 +11,42 @@ For more information on how to install, run and code with Mantaflow, please head
 
 ![mantaflow logo](resources/mantaflow-logo1.png)
 
+## Building from source ##
+
+This installation guide focusses on Ubuntu 24.04 as a distribution. The process will however look very similar with other distributions, the main differences being the package manager and library package names.
+
+First, install a few pre-requisites:
+
+    sudo apt install pt-get install cmake g++ git python3-dev qt5-qmake libqt5opengl5-dev libtbb-dev libopenvdb-dev
+
+If you want to enable CUDA support, additionally get the latest toolkit from nVidia, and install the appropriate developer driver (be careful though, these driver tend to wreck X11 - get some installation instructions from the web if this is the first time you install CUDA on Linux)
+
+Then, change to the directory to install the source code in, and obtain the current sources from the repository (or alternatively download and extract a source code package)
+
+    git clone https://github.com/thunil/mantaflow.git
+
+To build the project using CMake, set up a build directory and choose the build options (explanation):
+
+    mkdir mantaflow/build
+    cd mantaflow/build
+    cmake .. -DGUI=ON -DOPENVDB=ON
+    make -j8
+
+To build Mantaflow with OpenVDB and Threading Building Blocks (TBB) support, you need to disable GUI. There is an issue with duplicated symbols between Qt and Threading Building Blocks (TBB):
+
+    cmake .. -DTBB=ON -DOPENVDB=ON
+
+That's it! You can now test mantaflow using an example scene
+
+    ./manta ../scenes/simpleplume.py
+
+## Run tests ##
+
+Generate reference date and run tests:
+
+    cd tools/tests
+    MANTA_GEN_TEST_DATA=1 ./runTests.py ../../build/manta
+
+Run tests:
+
+    ./runTests.py ../../build/manta

tensorflow/example2_liquid/tf_train.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python2
+#!/usr/bin/python3
 
 # ----------------------------------------------------------------------------
 #

tools/getGitVersion.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python3
 import os
 import shutil
 import sys

tools/tests/quickRunTfTests.py

@@ -3,7 +3,7 @@
 # assume it's called from tools/tests
 os.chdir("../../tensorflow")
 
-pyExe = "python"
+pyExe = "python3"
 mantaExe = "/Users/sinithue/devel/manta/buildMaster/manta"
 dataPath = "./data"
 

tools/tests/runTests.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python3
 #
 # Simple script to run all base tests
 # The test scripts are named test_XXXX_description.py