static int cpVect_near(lua_State *L) {
cpVect v1 = check_cpVect(L, 1);
cpVect v2 = check_cpVect(L, 3);
cpFloat d = (cpFloat)luaL_checknumber(L, 5);
lua_pushboolean(L, cpvnear(v1, v2, d));
return 1;
}
// Recursive function used by cpPolylineSimplifyCurves().
static cpPolyline *
DouglasPeucker(
cpVect *verts, cpPolyline *reduced,
int length, int start, int end,
cpFloat min, cpFloat tol
){
// Early exit if the points are adjacent
if((end - start + length)%length < 2) return reduced;
cpVect a = verts[start];
cpVect b = verts[end];
// Check if the length is below the threshold
if(cpvnear(a, b, min) && cpPolylineIsShort(verts, length, start, end, min)) return reduced;
// Find the maximal vertex to split and recurse on
cpFloat max = 0.0;
int maxi = start;
cpVect n = cpvnormalize(cpvperp(cpvsub(b, a)));
cpFloat d = cpvdot(n, a);
for(int i=Next(start, length); i!=end; i=Next(i, length)){
cpFloat dist = fabs(cpvdot(n, verts[i]) - d);
if(dist > max){
max = dist;
maxi = i;
}
}
if(max > tol){
reduced = DouglasPeucker(verts, reduced, length, start, maxi, min, tol);
reduced = cpPolylinePush(reduced, verts[maxi]);
reduced = DouglasPeucker(verts, reduced, length, maxi, end, min, tol);
}
return reduced;
}
static void
update(int ticks)
{
int steps = 1;
cpFloat dt = 1.0f/60.0f/(cpFloat)steps;
for(int i=0; i<steps; i++){
// turn the control body based on the angle relative to the actual body
cpVect mouseDelta = cpvsub(mousePoint, tankBody->p);
cpFloat turn = cpvtoangle(cpvunrotate(tankBody->rot, mouseDelta));
cpBodySetAngle(tankControlBody, tankBody->a - turn);
// drive the tank towards the mouse
if(cpvnear(mousePoint, tankBody->p, 30.0)){
tankControlBody->v = cpvzero; // stop
} else {
cpFloat direction = (cpvdot(mouseDelta, tankBody->rot) > 0.0 ? 1.0 : -1.0);
tankControlBody->v = cpvrotate(tankBody->rot, cpv(30.0f*direction, 0.0f));
}
cpSpaceStep(space, dt);
}
}
static cpBool
cpCircleShapePointQuery(cpCircleShape *circle, cpVect p){
return cpvnear(circle->tc, p, circle->r);
}
static cpBool
cpCircleShapePointQuery(cpShape *shape, cpVect p){
cpCircleShape *circle = (cpCircleShape *)shape;
return cpvnear(circle->tc, p, circle->r);
}
