private bool HandleCollision(SweepCallback callback)
{
// set up for callback
cumulative_t += t;
float dir = step[axis];
// vector moved so far, and left to move
float done = t / max_t;
for (int i = 0; i < 3; i++)
{
float dv = vec[i] * done;
bas[i] += dv;
max[i] += dv;
left[i] = vec[i] - dv;
}
// set leading edge of stepped axis exactly to voxel boundary
// else we'll sometimes rounding error beyond it
if (dir > 0)
{
max[axis] = (float)Math.Round(max[axis]);
}
else
{
bas[axis] = (float)Math.Round(bas[axis]);
}
// call back to let client update the "left to go" vector
Vector3 leftVec = new Vector3(left[0], left[1], left[2]);
bool res = callback(cumulative_t, axis, dir, ref leftVec);
leftVec.CopyTo(left);
// bail out out on truthy response
if (res)
{
return(true);
}
// init for new sweep along vec
for (int i = 0; i < 3; i++)
{
vec[i] = left[i];
}
Initialize();
if (max_t == 0)
{
return(true); // no vector left
}
return(false);
}
// Return total distance moved
// (not necessarily magnitude of [end]-[start])
public float Execute(ref BoundingBox boundingBox,
Vector3 direction, SweepCallback callback, bool noTranslate)
{
Vector3 maximum = boundingBox.Maximum();
direction.CopyTo(sdir);
direction.CopyTo(vec);
maximum.CopyTo(max);
maximum.CopyTo(bmax);
boundingBox.Position.CopyTo(bas);
boundingBox.Position.CopyTo(bbas);
cumulative_t = 0;
axis = 0;
// init for the current sweep vector and take first step
Initialize();
if (max_t == 0)
{
return(0);
}
axis = StepForward();
float dist = 0;
bool done = false;
// loop along raycast vector
while (t <= max_t)
{
// sweeps over leading face of AABB
if (CheckCollision(axis))
{
// calls the callback and decides whether to continue
done = HandleCollision(callback);
if (done)
{
dist = cumulative_t;
break;
}
}
axis = StepForward();
}
if (!done)
{
cumulative_t += max_t;
for (int i = 0; i < 3; i++)
{
bas[i] += vec[i];
max[i] += vec[i];
}
dist = cumulative_t;
}
if (!noTranslate)
{
for (int i = 0; i < 3; i++)
{
result[i] = (sdir[i] > 0) ?
(max[i] - bmax[i]) : (bas[i] - bbas[i]);
}
boundingBox = boundingBox.Translated(new Vector3(
result[0], result[1], result[2]));
}
return(dist);
}
