UPBGE: Use bullet 3 and support multithreading physics. (#721)

The bullet library used by blender and game engine is update to the latest bullet 3
version. Only minor modification were requeired for the switch.

This bullet version allow multi threading for rigid body collision and constraints,
the main world for this prupose is btDiscretDynamicsWorldMt. Unfortunatly this
class doesn't manage soft bodies and to fill this gap btSoftRigidDynamicsWorldMt
which is a copy of btSoftRigidDynamics on top of btDiscretDynamicsWorldMt.
Once these modification the world is initialised with a special dispatcher and
a constraint solver pool for multi threading. The solver pool own as many regular
solver by threads available.

A compatiblity issue is introduced in KX_CharacterWrapper, bullet now supports vector
for the gravity instead of simple float, then a vector is exposed into the API.

Tests:
2700 spheres on two planes :
		Previous	Current
Begining	100ms		70ms
Stable		21ms		7.5ms

16000 point constraints on 10 cube chains.
		Previous	Current
		141ms		75ms

CMakeLists.txt

@@ -1325,7 +1325,7 @@ if(WITH_BULLET AND WITH_SYSTEM_BULLET)
 		set(WITH_BULLET OFF)
 	endif()
 else()
-	set(BULLET_INCLUDE_DIRS "${CMAKE_SOURCE_DIR}/extern/bullet2/src")
+	set(BULLET_INCLUDE_DIRS "${CMAKE_SOURCE_DIR}/extern/bullet/src")
 	# set(BULLET_LIBRARIES "")
 endif()
 

doc/python_api/rst/bge_types/bge.types.KX_CharacterWrapper.rst

@@ -17,7 +17,7 @@ base class --- :class:`EXP_PyObjectPlus`
 
       The gravity value used for the character.
 
-      :type: float
+      :type: :class:`mathutils.Vector`
 
    .. attribute:: fallSpeed
 

extern/CMakeLists.txt

@@ -42,7 +42,7 @@ add_subdirectory(wcwidth)
 
 if(WITH_BULLET)
 	if(NOT WITH_SYSTEM_BULLET)
-		add_subdirectory(bullet2)
+		add_subdirectory(bullet)
 	endif()
 endif()
 

extern/bullet/AUTHORS.txt

@@ -0,0 +1,45 @@
+Bullet Physics is created by Erwin Coumans with contributions from the following authors / copyright holders:
+
+AMD
+Apple
+Yunfei Bai
+Steve Baker
+Gino van den Bergen
+Jeff Bingham
+Nicola Candussi
+Erin Catto
+Lawrence Chai
+Erwin Coumans
+Disney Animation
+Benjamin Ellenberger
+Christer Ericson
+Google
+Dirk Gregorius
+Marcus Hennix
+Jasmine Hsu
+MBSim Development Team
+Takahiro Harada
+Simon Hobbs
+John Hsu
+Ole Kniemeyer
+Jay Lee
+Francisco Leon
+lunkhound
+Vsevolod Klementjev
+Phil Knight
+John McCutchan
+Steven Peters
+Roman Ponomarev
+Nathanael Presson
+Gabor PUHR
+Arthur Shek
+Russel Smith
+Sony
+Jakub Stephien
+Marten Svanfeldt
+Jie Tan
+Pierre Terdiman
+Steven Thompson
+Tamas Umenhoffer
+
+If your name is missing, please send an email to [email protected] or file an issue at http://github.com/bulletphysics/bullet3

extern/bullet/LICENSE.txt

@@ -0,0 +1,15 @@
+
+The files in this repository are licensed under the zlib license, except for the files under 'Extras' and examples/ThirdPartyLibs.
+
+Bullet Continuous Collision Detection and Physics Library
+http://bulletphysics.org
+
+This software is provided 'as-is', without any express or implied warranty.
+In no event will the authors be held liable for any damages arising from the use of this software.
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it freely,
+subject to the following restrictions:
+
+1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
+2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
+3. This notice may not be removed or altered from any source distribution.

extern/bullet/README.md

@@ -0,0 +1,119 @@
+
+[![Travis Build Status](https://api.travis-ci.org/bulletphysics/bullet3.png?branch=master)](https://travis-ci.org/bulletphysics/bullet3)
+[![Appveyor Build status](https://ci.appveyor.com/api/projects/status/6sly9uxajr6xsstq)](https://ci.appveyor.com/project/erwincoumans/bullet3)
+
+# Bullet Physics SDK
+
+This is the official C++ source code repository of the Bullet Physics SDK: real-time collision detection and multi-physics simulation for VR, games, visual effects, robotics, machine learning etc.
+
+New in Bullet 2.85: pybullet Python bindings, improved support for robotics and VR. Use pip install pybullet and see [PyBullet Quickstart Guide](https://docs.google.com/document/d/10sXEhzFRSnvFcl3XxNGhnD4N2SedqwdAvK3dsihxVUA/edit#heading=h.2ye70wns7io3).
+
+The Bullet 2 API will stay default and up-to-date while slowly moving to a new API.
+The steps towards a new API is in a nutshell:
+
+1. The old Bullet2 demos are being merged into the examples/ExampleBrowser
+2. A new physics-engine agnostic C-API is created, see examples/SharedMemory/PhysicsClientC_API.h
+3. Python bindings in pybullet are on top of this C-API, see examples/pybullet
+4. A Virtual Reality sandbox using openvr for HTC Vive and Oculus Rift is available
+5. The OpenCL examples in the ExampleBrowser can be enabled using --enable_experimental_opencl
+
+You can still use svn or svn externals using the github git repository: use svn co https://github.com/bulletphysics/bullet3/trunk
+
+## Requirements for Bullet 2
+
+A C++ compiler for C++ 2003. The library is tested on Windows, Linux, Mac OSX, iOS, Android,
+but should likely work on any platform with C++ compiler. 
+Some optional demos require OpenGL 2 or OpenGL 3, there are some non-graphical demos and unit tests too.
+
+## Contributors and Coding Style information
+
+https://docs.google.com/document/d/1u9vyzPtrVoVhYqQOGNWUgjRbfwfCdIts_NzmvgiJ144/edit
+
+## Requirements for experimental OpenCL GPGPU support
+
+The entire collision detection and rigid body dynamics can be executed on the GPU.
+
+A high-end desktop GPU, such as an AMD Radeon 7970 or NVIDIA GTX 680 or better.
+We succesfully tested the software under Windows, Linux and Mac OSX.
+The software currently doesn't work on OpenCL CPU devices. It might run
+on a laptop GPU but performance will not likely be very good. Note that
+often an OpenCL drivers fails to compile a kernel. Some unit tests exist to
+track down the issue, but more work is required to cover all OpenCL kernels.
+
+## License
+
+All source code files are licensed under the permissive zlib license
+(http://opensource.org/licenses/Zlib) unless marked differently in a particular folder/file.
+
+## Build instructions for Bullet using premake. You can also use cmake instead.
+
+**Windows**
+
+Click on build_visual_studio_vr_pybullet_double.bat and open build3/vs2010/0MySolution.sln
+When asked, convert the projects to a newer version of Visual Studio.
+If you installed Python in the C:\ root directory, the batch file should find it automatically.
+Otherwise, edit this batch file to choose where Python include/lib directories are located.
+
+**Windows Virtual Reality sandbox for HTC Vive and Oculus Rift**
+
+Build and run the App_SharedMemoryPhysics_VR project, preferably in Release/optimized build.
+You can connect from Python pybullet to the sandbox using:
+
+```
+import pybullet as p
+p.connect(p.SHARED_MEMORY) #or (p.TCP, "localhost", 6667) or (p.UDP, "192.168.86.10",1234)
+```
+
+**Linux and Mac OSX gnu make**
+
+Make sure cmake is installed (sudo apt-get install cmake, brew install cmake, or https://cmake.org)
+
+In a terminal type:
+
+	./build_cmake_pybullet_double.sh
+
+This script will invoke cmake and build in the build_cmake directory. You can find pybullet in Bullet/examples/pybullet.
+The BulletExampleBrowser binary will be in Bullet/examples/ExampleBrowser.
+
+You can also build Bullet using premake. There are premake executables in the build3 folder.
+Depending on your system (Linux 32bit, 64bit or Mac OSX) use one of the following lines
+Using premake:
+```
+	cd build3
+	./premake4_linux --double gmake
+	./premake4_linux64 --double gmake
+	./premake4_osx --double --enable_pybullet gmake
+```
+Then
+```
+	cd gmake
+	make
+```
+
+Note that on Linux, you need to use cmake to build pybullet, since the compiler has issues of mixing shared and static libraries.
+
+**Mac OSX Xcode**
+
+Click on build3/xcode4.command or in a terminal window execute
+
+	./premake_osx xcode4
+
+## Usage
+
+The App_ExampleBrowser executables will be located in the bin folder.
+You can just run it though a terminal/command prompt, or by clicking it.
+
+
+```
+[--start_demo_name="Demo Name"]     Start with a selected demo  
+[--mp4=moviename.mp4]               Create a mp4 movie of the window, requires ffmpeg installed
+[--mouse_move_multiplier=0.400000]  Set the mouse move sensitivity
+[--mouse_wheel_multiplier=0.01]     Set the mouse wheel sensitivity
+[--background_color_red= 0.9]       Set the red component for background color. Same for green and blue
+[--fixed_timestep= 0.0]             Use either a real-time delta time (0.0) or a fixed step size (0.016666)
+```
+
+You can use mouse picking to grab objects. When holding the ALT or CONTROL key, you have Maya style camera mouse controls.
+Press F1 to create a series of screenshots. Hit ESCAPE to exit the demo app.
+
+Check out the docs folder and the Bullet physics forums for further information.

extern/bullet/VERSION

@@ -0,0 +1 @@
+2.88