Gamestudio/A8 Physics

Gamestudio/A8 contains a physics subsystem based on the PhysX™ Engine by nVIDIA, which allows for realistic motion of models. The basic functions support rigid bodies and joints. With additional plugins, deformable bodies, liquids, cloth and many other effects can be supported. The source code of the PhysX implementation is available as Open Source, so with some C++ knowledge you can implement any additional physics functions.

Because this type of simulation is CPU resp. GPU intensive, the physics subsystem is disabled by default. When you wish to use it, include the ackphysx.h header, and call physX_open(). Afterwards you can load a level and register dynamic physics objects for the simulation. This delegates exclusive motion control of those objects to the engine; they can not be moved anymore by changing their position. When you no longer need a physics entity, unregister it or disable the physics system.

Functions Overview

Include Physics in your Game

• Include <ackphysx.h> in your main.c file, after <acknex.h> or <default.c>.
• Call physX_open() before loading the first level. This automatically registers level geometry and static models as physics obstacles.
• Call pXent_settype(entity,...) to register dynamic entities for physics.
• If desired, set the object's attributes ( pXent_setelasticity, pXent_setdamping etc).

Example

#include <default.c>
#include <ackphysx.h>

function main()
{
  physX_open();
  level_load(""); // load an empty level
  vec_set(camera.x,vector(-100,0,30));
  pXent_settype(NULL,PH_STATIC,PH_PLANE); // create a static plane at groundlevel zero
  
  ENTITY* ball = ent_create(SPHERE_MDL,vector(0,0,100),NULL);
  pXent_settype(ball,PH_RIGID,PH_SPHERE ); // create a ball
  pXent_setelasticity(ball,50);
  pXent_addvelcentral(ball,vector(0,-10,0)); // make it jump and roll sidewards

  while(1){
    pX_pick(); // pick and move the ball with the cursor
    wait(1);
  }
}

Publishing a PhysX game

When your game uses PhysX commands, the recent PhysX System Software by nVidia must be installed on the target system. You are also required to include the PhysX logo in press releases and on your splash or credit screens. The standard splash screen already contains the PhysX logo. You can find the detailed deployment requirements in the PhysX EULA.

When you publish a PhysX application, the DLLs ackphysX.dll, PhysXCore.dll, PhysXDevice.dll, PhysXLoader.dll, PhysXCooking.dll, NxCharacter.dll and cudart32_30_9.dll are automatically bound to the project and copied to the .CD folder. For version A8.20 or below, you also need to make sure that the end user has installed the PhysX System Software on her PC. Either provide a link for your users to download it from the nVidia Download Page (http://www.nvidia.com/object/physx_system_software.html). Or - preferably - include it in your installation program, or let your application install it through the exec_wait command. You can silently install the software with the command line option /quiet. Examples for automatic installation:

// installing PhysX from the application folder
function main()
{
  if (!physX_open()) {
    printf("Install PhysX System Software");
    exec_wait("PhysX_9.10.0224_SystemSoftware.exe","/quiet"); // insert the recent filename here
    printf("PhysX System Software installed!\nPlease restart your PC now!");
    sys_exit(NULL);
  }
  ...

// installing PhysX from the nVidia Website
function main()
{
  if (!physX_open()) {
    printf("Install PhysX System Software from the web");
    exec("http://www.nvidia.com/object/physx_system_software.html",NULL); 
    printf("After installing, please restart your PC!");
    sys_exit(NULL);
  }
  ...

Credits

See also: