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Rewrote collision handling for Floatation
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@heinermann
heinermann committed Mar 8, 2020
1 parent 891f536 commit 99f69da
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Showing 2 changed files with 94 additions and 123 deletions.
204 changes: 84 additions & 120 deletions Floating/Collision.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -2,160 +2,124 @@

namespace Heinermann.Floating
{
public static class Collision
public class CollisionResolver
{
public static void ApplyBoxColliderRestrictionsX(ref GravityComponent grav, ref Vector2 newPosition)
{
KBoxCollider2D collider = grav.transform.GetComponent<KBoxCollider2D>();
public GravityComponent grav;
Vector2 desiredPosition;
Vector2 currentPosition;

Vector2 oldPosition = grav.transform.position;
Vector2 diffPosition = newPosition - oldPosition;
public Vector2 bestPosition;
float bestDistance;

float xDirection = Mathf.Sign(diffPosition.x);
Bounds bounds;

Bounds bounds = collider.bounds;
bounds.center += (Vector3)diffPosition;
public CollisionResolver(GravityComponent grav, Vector2 desiredPosition)
{
this.grav = grav;
this.currentPosition = grav.transform.position;
this.desiredPosition = desiredPosition;

Vector2 min = bounds.min;
Vector2 max = bounds.max;
bestDistance = float.PositiveInfinity;
bestPosition = currentPosition;

float extentX = collider.bounds.extents.x + 0.01f;
for (
Vector2 iterator = new Vector2(xDirection < 0 ? min.x : max.x, Mathf.Floor(min.y));
iterator.y <= max.y;
iterator.y += 1f)
KCollider2D collider = grav.transform.GetComponent<KCollider2D>();
if (collider != null)
{
if (Helpers.IsSolidCell(iterator))
{
grav.velocity.x = 0f;

float offset = xDirection < 0 ? 1f + extentX : -extentX;
newPosition.x = Mathf.Floor(iterator.x) + offset;
break;
}
this.bounds = collider.bounds;
bounds.Expand(0.05f); // Apply breathing room
}
}

public static void ApplyBoxColliderRestrictionsY(ref GravityComponent grav, ref Vector2 newPosition)
/**
* Checks if bounds intersects a solid cell.
*/
bool IntersectsSolidCell(Vector2 target)
{
KBoxCollider2D collider = grav.transform.GetComponent<KBoxCollider2D>();

Vector2 oldPosition = grav.transform.position;
Vector2 diffPosition = newPosition - oldPosition;

float yDirection = Mathf.Sign(diffPosition.y);

Bounds bounds = collider.bounds;
bounds.center += (Vector3)diffPosition;

float extentY = Helpers.GetYExtent(grav);
float minY = bounds.center.y - extentY;
float maxY = bounds.center.y + extentY;

for (
Vector2 iterator = new Vector2(Mathf.Floor(bounds.min.x), yDirection < 0 ? minY : maxY);
iterator.x <= bounds.max.x;
iterator.x += 1f)
bounds.center = target;
Vector3 min = bounds.min;
Vector3 max = bounds.max;

if (Helpers.IsSolidCell(min) ||
Helpers.IsSolidCell(max) ||
Helpers.IsSolidCell(new Vector2(min.x, max.y)) ||
Helpers.IsSolidCell(new Vector2(max.x, min.y)))
{
if (Helpers.IsSolidCell(iterator))
{
grav.velocity.y = 0f;

float offset = yDirection < 0 ? 1f + extentY : -extentY;
newPosition.y = Mathf.Floor(iterator.y) + offset;
break;
}
return true;
}
}

public static void ApplyBoxColliderRestrictions(ref GravityComponent grav, ref Vector2 newPosition)
{
Vector2 proposalA = newPosition;
ApplyBoxColliderRestrictionsX(ref grav, ref proposalA);
ApplyBoxColliderRestrictionsY(ref grav, ref proposalA);

Vector2 proposalB = newPosition;
ApplyBoxColliderRestrictionsY(ref grav, ref proposalB);
ApplyBoxColliderRestrictionsX(ref grav, ref proposalB);

if ((proposalA - newPosition).sqrMagnitude < (proposalB - newPosition).sqrMagnitude)
// If the length is greater than one tile, it's possible to have a body get stuck
// because none of the 4 corners hit the tile.
// They look like beefy loops but won't even fire 99% of the time.
for (float x = min.x + 1f; x < max.x; x += 1f)
{
newPosition = proposalA;
if (Helpers.IsSolidCell(new Vector2(x, min.y)) || Helpers.IsSolidCell(new Vector2(x, max.y)))
{
return true;
}
}
else
for (float y = min.y + 1f; y < max.y; y += 1f)
{
newPosition = proposalB;
if (Helpers.IsSolidCell(new Vector2(min.x, y)) || Helpers.IsSolidCell(new Vector2(max.x, y)))
{
return true;
}
}
return false;
}

public static void ApplyRadiusRestrictionsX(ref GravityComponent grav, ref Vector2 newPosition)
bool CheckResolves(Vector2 target)
{
float radius = Helpers.GetYExtent(grav) + 0.001f;

Vector2 left = newPosition + Vector2.left * radius;
Vector2 right = newPosition + Vector2.right * radius;
if (Helpers.IsSolidCell(left))
{
newPosition.x = Mathf.Floor(left.x) + 1f + radius;
grav.velocity.x = 0f;
}
else if (Helpers.IsSolidCell(right))
float newDist = (target - currentPosition).sqrMagnitude;
if (newDist < bestDistance && !IntersectsSolidCell(target))
{
newPosition.x = Mathf.Floor(right.x) - radius;
grav.velocity.x = 0f;
bestPosition = target;
bestDistance = newDist;
return true;
}
return false;
}

public static void ApplyRadiusRestrictionsY(ref GravityComponent grav, ref Vector2 newPosition)
bool SpiralSearchCollision()
{
float radius = Helpers.GetYExtent(grav) + 0.001f;

Vector2 up = newPosition + Vector2.up * radius;
Vector2 down = newPosition + Vector2.down * radius;
if (Helpers.IsSolidCell(up))
{
Vector2 sourcePos = newPosition;
newPosition.y = Mathf.Floor(up.y) - radius;
grav.velocity.y = 0f;
}
else if (Helpers.IsSolidCell(down))
Vector2 search = Vector2.zero;
Vector2 dir = new Vector2(1f, 0f);
Vector2 total = Vector2.zero;
float limit = 0.1f;
while (limit <= 2f)
{
newPosition.y = Mathf.Floor(down.y) + 1f + radius;
grav.velocity.y = 0f;
search += dir * 0.1f;
total += dir * 0.1f;
if (CheckResolves(currentPosition + search)) return true;

if (total.magnitude >= limit)
{
dir = Vector2.Perpendicular(dir);
if (Mathf.Abs(total.y) >= limit)
{
limit += 0.1f;
}
total = Vector2.zero;
}
}
return false;
}

public static void ApplyRadiusRestrictions(ref GravityComponent grav, ref Vector2 newPosition)
public void ResolveCollisions()
{
Vector2 proposalA = newPosition;
ApplyRadiusRestrictionsX(ref grav, ref proposalA);
ApplyRadiusRestrictionsY(ref grav, ref proposalA);
if (CheckResolves(desiredPosition)) return;

Vector2 proposalB = newPosition;
ApplyRadiusRestrictionsY(ref grav, ref proposalB);
ApplyRadiusRestrictionsX(ref grav, ref proposalB);
bool canMoveX = CheckResolves(new Vector2(desiredPosition.x, currentPosition.y));
bool canMoveY = CheckResolves(new Vector2(currentPosition.x, desiredPosition.y));

if (!canMoveY) grav.velocity.y = 0;
if (!canMoveX) grav.velocity.x = 0;
if (canMoveX || canMoveY) return;

if ((proposalA - newPosition).sqrMagnitude < (proposalB - newPosition).sqrMagnitude)
{
newPosition = proposalA;
}
else
{
newPosition = proposalB;
}
}
if (CheckResolves(currentPosition)) return;

// TODO: Better resolution, since bad axis can trigger and shift things weirdly
public static void ApplyGuardRails(ref GravityComponent grav, ref Vector2 newPosition)
{
if (grav.transform.GetComponent<KBoxCollider2D>() != null)
{
ApplyBoxColliderRestrictions(ref grav, ref newPosition);
}
else
{
ApplyRadiusRestrictions(ref grav, ref newPosition);
}
if (SpiralSearchCollision()) return;

Debug.LogWarning("[Floatation] FAILED to resolve object collision - object is stuck.");
}
}
}
13 changes: 10 additions & 3 deletions Floating/Patches/GravityComponents.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -83,11 +83,18 @@ static void Prefix(ref GravityComponents __instance, float dt)
ApplyYVelocityChanges(ref grav, dt);

Vector3 pos = grav.transform.GetPosition();
Vector2 newPosition = (Vector2)pos + grav.velocity * dt;
Vector3 newPosition = (Vector2)pos + grav.velocity * dt;

Collision.ApplyGuardRails(ref grav, ref newPosition);
grav.transform.SetPosition(new Vector3(newPosition.x, newPosition.y, pos.z));
// Resolve collisions
CollisionResolver resolver = new CollisionResolver(grav, newPosition);
resolver.ResolveCollisions();

// Apply the new gravity/position
newPosition = resolver.bestPosition;
newPosition.z = pos.z;
grav = resolver.grav;

grav.transform.SetPosition(newPosition);
grav.elapsedTime += dt;

gravComponentState.Add(i, grav);
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