marko10_000
/
openclonk
forked from Mirrors/openclonk
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Rope: Apply sticking friction

rope
Armin Burgmeier 2012-04-29 15:36:06 +02:00
parent 56282e6168
commit a2997fc763
1 changed files with 25 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
src/object/C4Rope.cpp
View File

@ -106,11 +106,29 @@ void C4RopeSegment::AddForce(C4Real x, C4Real y)
void C4RopeSegment::Execute(C4Real dt, C4Real mu)
{
vx += dt * fx / m;
vy += dt * fy / m;
int old_x = fixtoi(x);
int old_y = fixtoi(y);
// Sticking friction: If an object has contact with the landscape and it
// is at rest then one needs to exceed a certain threshold force until it
// starts moving.
if(GBackSolid(old_x+1, old_y) || GBackSolid(old_x-1, old_y) || GBackSolid(old_x, old_y-1) || GBackSolid(old_x, old_y+1))
{
if(vx*vx + vy*vy < Fix1)
{
if(fx*fx + fy*fy < Fix1*4)
{
fx = fy = Fix0;
vx = vy = Fix0;
return;
}
}
}
vx += dt * fx / m;
vy += dt * fy / m;
fx = fy = Fix0;
int new_x = fixtoi(x + dt * vx);
int new_y = fixtoi(y + dt * vy);
int max_p = Max(abs(new_x - old_x), abs(new_y - old_y));
@ -142,10 +160,14 @@ void C4RopeSegment::Execute(C4Real dt, C4Real mu)
C4Real vy2 = Sin75 * vx + Cos75 * vy;
const C4Real d = ftofix(sqrt(fixtof(vx*vx + vy*vy)));
// TODO: 5 should maybe not be hardcoded but depend on the magnitude of the force applied, and
// we should check more than a single pixel. There's some more potential for optimization here.
if(d != Fix0 && !GBackSolid(fixtoi(x + vx1*5/d), fixtoi(y + vy1*5/d)))
{ fx += mu * vx1; fy += mu * vy1; }
else if(d != Fix0 && !GBackSolid(fixtoi(x + vx2*5/d), fixtoi(y + vy2*5/d)))
{ fx += mu * vx2; fy += mu * vy2; }
else
vx = vy = Fix0; //
break;
}
@ -158,7 +180,6 @@ void C4RopeSegment::Execute(C4Real dt, C4Real mu)
{
x += dt * vx;
y += dt * vy;
fx = fy = Fix0;
}
}