pal - Physics Abstraction Layer

Your best "pal" when push comes to shove....

Introduction

PAL is a C++ physics abstraction system. This allows you to rapidly develop applications that support various physics engines.

Goal:

Provide a single, flexible API to access a variety of physics engines.

Available Implementations:

PAL is available for: (alphabetical listing)

• AGEIA PhysX http://www.ageia.com/ [* - same as NovodeX]
• Box2D http://www.box2d.org/ [* - experimental implementation]
• Bullet http://www.continuousphysics.com/Bullet/
• Dynamechs http://dynamechs.sourceforge.net/ [* - implementation permanently disabled]
• Havok http://www.havok.com/
• IBDS http://www.impulse-based.de/ [* - experimental implementation]
• Jiggle http://www.rowlhouse.co.uk/jiglib/
• Meqon http://www.meqon.com/ [* - implementation permanently disabled]
• Newton http://www.physicsengine.com/
• NovodeX http://www.novodex.com/ [* - same as AGEIA,nVidia]
• nVidia PhysX [* - same as NovodeX]
• ODE http://www.ode.org/
• OpenTissue http://www.opentissue.org/ [* - experimental implementation]
• Simple Physics Engine http://spehome.com/
• Tokamak http://www.tokamakphysics.com/
• True Axis http://trueaxis.com/

Installation

• Install framework
• Install PAL

If you wish to use all of PAL's extended functionality:

• Install tinyXML
• Install libSDL
• Install boost

Requirements

The following compilers are currently supported:

Microsoft:

• Microsoft Visual C++ 6.0
• Microsoft Visual C++ 7.0, 7.1 (.NET)
• Microsoft Visual C++ 8.0

GNU

• GCC 3.2 and above

PAL Information

• Coordinates used for any functions are specified in world coordinates.
• Angular measurements are in radians.

Example

Just starting?

Try the simple examples. Then take a look at palFactory and follow the documentation links!

Tiny example of using PAL directly

• Make sure all the PAL & framework files are correctly included in your project

        PF->SelectEngine(szEngine); //szEngine is the name of the engine you wish to use. eg:"ODE"
        palPhysics *pp = PF->CreatePhysics(); //create the main physics class
        pp->Init(0,-9.8f,0); //initialize it, set the main gravity vector
        palTerrainPlane *pt= PF->CreateTerrainPlane(); //create the ground
        pt->Init(0,0,0,50.0f); //initialize it, set its location to 0,0,0 and minimum size to 50
        palBox *pb = PF->CreateBox(); //create a box
        pb->Init(0,5,0, 1,1,1, 1); //initialize it, set its location to 0,5,0 (five units up in the air), set dimensions to 1x1x1 and its mass to 1
        while (!quit) { //loop until done
                pp->Update(0.02f); //update the physics engine. advance the simulation time by 0.02

                palMatrix4x4 m;
                m=pb->GetLocationMatrix(); //get the location of the box (transformation matrix)
                //display the box
        }

        PF->Cleanup(); //we are done with the physics. clean up.

Example of using PAL via XML

NOTE: PAL XML is now unsupported, try PAL COLLADA and PAL Scythe instead **

• Make sure all the PAL & framework files are correctly included in your project
• Make sure tinyXML and the xml files are correctly included in your project

        palXMLFactory px;
        px.LoadXML(szFilename); //eg:"physics.xml"
        palPhysics *pp = palGetObject<palPhysics>("Physics"); //get the physics engine described in the XML file
        palBox *pb = palGetObject<palBox>("box0"); //get the box described in the XML file - all objects can also be accessed via a public vector array in the XML factory
        while (!quit) { //loop until done
                pp->Update(0.02f); //update the physics engine. advance the simulation time by 0.02

                palMatrix4x4 m;
                m=pb->GetLocationMatrix(); //get the location of the box (transformation matrix)
                //display the box
        }

         PF->Cleanup(); //we are done with the physics. clean up.

Credits

PAL created by Adrian Boeing.

Diagrams created by Martin Sawtell.

Some code based from ODE and MESA libraries.