/* * This file is part of MXE. See LICENSE.md for licensing information. */ // taken from: doc/examples/Hello Chipmunk.html#include <stdio.h>#include <chipmunk/chipmunk.h> int main(void){    // cpVect is a 2D vector and cpv() is a shortcut for initializing them.    cpVect gravity = cpv(0, -100);     // Create an empty space.    cpSpace *space = cpSpaceNew();    cpSpaceSetGravity(space, gravity);     // Add a static line segment shape for the ground.    // We'll make it slightly tilted so the ball will roll off.    // We attach it to a static body to tell Chipmunk it shouldn't be movable.    cpShape *ground = cpSegmentShapeNew(cpSpaceGetStaticBody(space), cpv(-20, 5), cpv(20, -5), 0);    cpShapeSetFriction(ground, 1);    cpSpaceAddShape(space, ground);     // Now let's make a ball that falls onto the line and rolls off.    // First we need to make a cpBody to hold the physical properties of the object.    // These include the mass, position, velocity, angle, etc. of the object.    // Then we attach collision shapes to the cpBody to give it a size and shape.     cpFloat radius = 5;    cpFloat mass = 1;     // The moment of inertia is like mass for rotation    // Use the cpMomentFor*() functions to help you approximate it.    cpFloat moment = cpMomentForCircle(mass, 0, radius, cpvzero);     // The cpSpaceAdd*() functions return the thing that you are adding.    // It's convenient to create and add an object in one line.    cpBody *ballBody = cpSpaceAddBody(space, cpBodyNew(mass, moment));    cpBodySetPosition(ballBody, cpv(0, 15));     // Now we create the collision shape for the ball.    // You can create multiple collision shapes that point to the same body.    // They will all be attached to the body and move around to follow it.    cpShape *ballShape = cpSpaceAddShape(space, cpCircleShapeNew(ballBody, radius, cpvzero));    cpShapeSetFriction(ballShape, 0.7);     // Now that it's all set up, we simulate all the objects in the space by    // stepping forward through time in small increments called steps.    // It is *highly* recommended to use a fixed size time step.    cpFloat timeStep = 1.0/60.0;    for(cpFloat time = 0; time < 2; time += timeStep){        cpVect pos = cpBodyGetPosition(ballBody);        cpVect vel = cpBodyGetVelocity(ballBody);        printf(          "Time is %5.2f. ballBody is at (%5.2f, %5.2f). It's velocity is (%5.2f, %5.2f)\n",          time, pos.x, pos.y, vel.x, vel.y        );         cpSpaceStep(space, timeStep);    }     // Clean up our objects and exit!    cpShapeFree(ballShape);    cpBodyFree(ballBody);    cpShapeFree(ground);    cpSpaceFree(space);     return 0;}