這展示了一個超級簡單的示例程序，它使用了ODE (Open Dynamics Engine)。在許多編程書籍中，打印“Hellow World”是第一個示例程序。對於物理仿真模擬編程來說，我認為自由落體模擬是最簡單的例子。
主要包含知識點：創建world，創建body。
創建世界和地面：
1 world = dWorldCreate(); 2 space = dHashSpaceCreate(0); 3 contactgroup = dJointGroupCreate(0); 4 dWorldSetGravity(world, 0, 0, -9.8); 5 ground = dCreatePlane(space, 0, 0, 1, 0);
創建實物：
1 dMass m1; 2 dReal x0 = 0.0, y0 = 0.0, z0 = 2.5; 3 ball.radius = 0.2; 4 ball.mass = 1.0; 5 ball.body = dBodyCreate(world); 6 dMassSetZero(&m1); 7 dMassSetSphereTotal(&m1, ball.mass, ball.radius); 8 dBodySetMass(ball.body, &m1); 9 dBodySetPosition(ball.body, x0, y0, z0); 10 ball.geom = dCreateSphere(space, ball.radius); 11 dGeomSetBody(ball.geom, ball.body);
詳細程序：
#include <ode/ode.h> #include <drawstuff/drawstuff.h> #include "texturepath.h" #ifdef dDOUBLE #define dsDrawSphere dsDrawSphereD #endif static dWorldID world; static dBodyID ball; const dReal radius = 0.2; const dReal mass = 1.0; static void simLoop(int pause) { const dReal* pos, * R; dWorldStep(world, 0.05); dsSetColor(1.0, 0.0, 0.0); pos = dBodyGetPosition(ball); R = dBodyGetRotation(ball); dsDrawSphere(pos, R, radius); } void start() { static float xyz[3] = { 0.0,-3.0,1.0 }; static float hpr[3] = { 90.0,0.0,0.0 }; dsSetViewpoint(xyz, hpr); } int main(int argc, char** argv) { dReal x0 = 0.0, y0 = 0.0, z0 = 1.0; dMass m1; // setup pointers to drawstuff callback functions dsFunctions fn; fn.version = DS_VERSION; fn.start = &start; fn.step = &simLoop; fn.command = NULL; fn.stop = 0; fn.path_to_textures = DRAWSTUFF_TEXTURE_PATH; // create world dInitODE2(0); world = dWorldCreate(); dWorldSetGravity(world, 0, 0, 0.0001); // create ball ball = dBodyCreate(world); dMassSetZero(&m1); dMassSetSphereTotal(&m1, mass, radius); dBodySetMass(ball, &m1); dBodySetPosition(ball, x0, y0, z0); // run simulation dsSimulationLoop(argc, argv, 352, 288, &fn); dWorldDestroy(world); dCloseODE(); }