fixup! server/block: Add ProjectileHitter interface

Author: DaPigGuy

server/entity/projectile.go

@@ -297,19 +297,22 @@ func (lt *ProjectileBehaviour) tickMovement(e *Ent, tx *world.Tx) (*Movement, tr
 	if !mgl64.FloatEqual(end.Sub(pos).LenSqr(), 0) {
 		if hit, ok = trace.Perform(pos, end, tx, e.H().Type().BBox(e).Grow(1.0), lt.ignores(e)); ok {
 			if r, ok := hit.(trace.BlockResult); ok {
-				// Undo the gravity because the velocity as a result of gravity
-				// at the point of collision should be 0.
-				vel[1] = (vel[1] + lt.mc.Gravity) / (1 - lt.mc.Drag)
-				x, y, z := vel.Mul(lt.conf.BlockCollisionVelocityMultiplier).Elem()
-				// Calculate multipliers for all coordinates: 1 for the ones that
-				// weren't on the same axis as the one collided with, -1 for the one
-				// that was on that axis to deflect the projectile.
-				mx, my, mz := hit.Face().Axis().Vec3().Mul(-2).Add(mgl64.Vec3{1, 1, 1}).Elem()
-
-				vel = mgl64.Vec3{x * mx, y * my, z * mz}
+				resultPos := r.BlockPosition()
+				if h, ok := tx.Block(resultPos).(block.ProjectileHitter); ok {
+					h.ProjectileHit(resultPos, tx, e, r.Face())
+				}
+				// Check that the block hit was not set to air by a block.ProjectileHitter.
+				if _, ok := tx.Block(resultPos).(block.Air); !ok {
+					// Undo the gravity because the velocity as a result of gravity
+					// at the point of collision should be 0.
+					vel[1] = (vel[1] + lt.mc.Gravity) / (1 - lt.mc.Drag)
+					x, y, z := vel.Mul(lt.conf.BlockCollisionVelocityMultiplier).Elem()
+					// Calculate multipliers for all coordinates: 1 for the ones that
+					// weren't on the same axis as the one collided with, -1 for the one
+					// that was on that axis to deflect the projectile.
+					mx, my, mz := hit.Face().Axis().Vec3().Mul(-2).Add(mgl64.Vec3{1, 1, 1}).Elem()
 
-				if h, ok := tx.Block(r.BlockPosition()).(block.ProjectileHitter); ok {
-					h.ProjectileHit(r.BlockPosition(), tx, e, r.Face())
+					vel = mgl64.Vec3{x * mx, y * my, z * mz}
 				}
 			} else {
 				vel = zeroVec3