@Override
  public void generate(
      AxionElementGenerationCallback callback,
      Vector3f position,
      Matrix4f rotation,
      String axionParameter) {
    Vector3f workVector = new Vector3f();

    callback.setMainBlock(position, baseBlock);
    int rangeInt = (int) range;
    for (int x = -rangeInt; x <= rangeInt; x++) {
      for (int y = -rangeInt; y <= rangeInt; y++) {
        for (int z = -rangeInt; z <= Math.min(rangeInt, maxZ); z++) {
          double distanceSquare = x * x + y * y + z * z;
          if (distanceSquare < innerRangeSquare) {
            workVector.set(x, y, z);
            rotation.transformVector(workVector);
            workVector.add(position);
            callback.setAdditionalBlock(workVector, baseBlock);
          } else if (distanceSquare < rangeSquare) {
            workVector.set(x, y, z);
            rotation.transformVector(workVector);
            workVector.add(position);
            callback.setAdditionalBlock(workVector, surroundBlock);
          }
        }
      }
    }

    callback.advance(advance);
  }
  private MoveResult move(
      final Vector3f startPosition,
      final Vector3f moveDelta,
      final float stepHeight,
      final float slopeFactor,
      final CharacterCollider collider) {
    steppedUpDist = 0;
    stepped = false;
    Vector3f position = new Vector3f(startPosition);
    boolean hitTop = false;
    boolean hitBottom = false;
    boolean hitSide;

    // Actual upwards movement
    if (moveDelta.y > 0) {
      hitTop = moveDelta.y - moveUp(moveDelta.y, collider, position) > physics.getEpsilon();
    }
    hitSide =
        moveHorizontal(
            new Vector3f(moveDelta.x, 0, moveDelta.z), collider, position, slopeFactor, stepHeight);
    if (moveDelta.y < 0 || steppedUpDist > 0) {
      float dist = (moveDelta.y < 0) ? moveDelta.y : 0;
      dist -= steppedUpDist;
      hitBottom = moveDown(dist, slopeFactor, collider, position);
    }
    if (!hitBottom && stepHeight > 0) {
      Vector3f tempPos = new Vector3f(position);
      hitBottom = moveDown(-stepHeight, slopeFactor, collider, tempPos);
      // Don't apply step down if nothing to step onto
      if (hitBottom) {
        position.set(tempPos);
      }
    }
    return new MoveResult(position, hitSide, hitBottom, hitTop);
  }
 private Vector3f extractResidualMovement(
     Vector3f hitNormal, Vector3f direction, float normalMag) {
   float movementLength = direction.length();
   if (movementLength > physics.getEpsilon()) {
     direction.normalize();
     Vector3f reflectDir = Vector3fUtil.reflect(direction, hitNormal, new Vector3f());
     reflectDir.normalize();
     Vector3f perpendicularDir =
         Vector3fUtil.getPerpendicularComponent(reflectDir, hitNormal, new Vector3f());
     if (normalMag != 0.0f) {
       Vector3f perpComponent = new Vector3f(perpendicularDir);
       perpComponent.scale(normalMag * movementLength);
       direction.set(perpComponent);
     }
   }
   return direction;
 }
  private boolean moveHorizontal(
      Vector3f horizMove,
      CharacterCollider collider,
      Vector3f position,
      float slopeFactor,
      float stepHeight) {
    float remainingFraction = 1.0f;
    float dist = horizMove.length();
    if (dist < physics.getEpsilon()) {
      return false;
    }
    boolean horizontalHit = false;
    Vector3f normalizedDir = Vector3fUtil.safeNormalize(horizMove, new Vector3f());

    if (collider == null) {
      // ignore collision
      normalizedDir.scale(dist);
      position.add(normalizedDir);
      return false;
    }

    Vector3f targetPos = new Vector3f(normalizedDir);
    targetPos.scale(dist + HORIZONTAL_PENETRATION_LEEWAY);
    targetPos.add(position);
    int iteration = 0;
    Vector3f lastHitNormal = new Vector3f(0, 1, 0);
    while (remainingFraction >= 0.01f && iteration++ < 10) {
      SweepCallback callback =
          collider.sweep(position, targetPos, HORIZONTAL_PENETRATION, slopeFactor);

      /* Note: this isn't quite correct (after the first iteration the closestHitFraction is only for part of the moment)
      but probably close enough */
      float actualDist =
          Math.max(
              0,
              (dist + HORIZONTAL_PENETRATION_LEEWAY) * callback.getClosestHitFraction()
                  - HORIZONTAL_PENETRATION_LEEWAY);
      if (actualDist != 0) {
        remainingFraction -= actualDist / dist;
      }
      if (callback.hasHit()) {
        if (actualDist > physics.getEpsilon()) {
          Vector3f actualMove = new Vector3f(normalizedDir);
          actualMove.scale(actualDist);
          position.add(actualMove);
        }
        dist -= actualDist;
        Vector3f newDir = new Vector3f(normalizedDir);
        newDir.scale(dist);
        float slope = callback.getHitNormalWorld().dot(new Vector3f(0, 1, 0));

        // We step up if we're hitting a big slope, or if we're grazing
        // the ground, otherwise we move up a shallow slope.
        if (slope < slopeFactor || 1 - slope < physics.getEpsilon()) {
          boolean stepping =
              checkStep(collider, position, newDir, callback, slopeFactor, stepHeight);
          if (!stepping) {
            horizontalHit = true;
            Vector3f newHorizDir = new Vector3f(newDir.x, 0, newDir.z);
            Vector3f horizNormal =
                new Vector3f(callback.getHitNormalWorld().x, 0, callback.getHitNormalWorld().z);
            if (horizNormal.lengthSquared() > physics.getEpsilon()) {
              horizNormal.normalize();
              if (lastHitNormal.dot(horizNormal) > physics.getEpsilon()) {
                break;
              }
              lastHitNormal.set(horizNormal);
              extractResidualMovement(horizNormal, newHorizDir);
            }
            newDir.set(newHorizDir);
          }
        } else {
          // Hitting a shallow slope, move up it
          Vector3f newHorizDir = new Vector3f(newDir.x, 0, newDir.z);
          extractResidualMovement(callback.getHitNormalWorld(), newDir);
          Vector3f modHorizDir = new Vector3f(newDir);
          modHorizDir.y = 0;
          newDir.scale(newHorizDir.length() / modHorizDir.length());
        }
        float sqrDist = newDir.lengthSquared();
        if (sqrDist > physics.getEpsilon()) {
          newDir.normalize();
          if (newDir.dot(normalizedDir) <= 0.0f) {
            break;
          }
        } else {
          break;
        }
        dist = (float) Math.sqrt(sqrDist);
        normalizedDir.set(newDir);
        targetPos.set(normalizedDir);
        targetPos.scale(dist + HORIZONTAL_PENETRATION_LEEWAY);
        targetPos.add(position);
      } else {
        normalizedDir.scale(dist);
        position.add(normalizedDir);
        break;
      }
    }
    return horizontalHit;
  }
  private boolean moveDown(
      float dist, float slopeFactor, CharacterCollider collider, Vector3f position) {
    if (collider == null) {
      position.y += dist;
      return false;
    }

    float remainingDist = -dist;
    Vector3f targetPos = new Vector3f(position);
    targetPos.y -= remainingDist + VERTICAL_PENETRATION_LEEWAY;
    Vector3f normalizedDir = new Vector3f(0, -1, 0);
    boolean hit = false;
    int iteration = 0;
    while (remainingDist > physics.getEpsilon() && iteration++ < 10) {
      SweepCallback callback = collider.sweep(position, targetPos, VERTICAL_PENETRATION, -1.0f);
      float actualDist =
          Math.max(
              0,
              (remainingDist + VERTICAL_PENETRATION_LEEWAY) * callback.getClosestHitFraction()
                  - VERTICAL_PENETRATION_LEEWAY);
      Vector3f expectedMove = new Vector3f(targetPos);
      expectedMove.sub(position);
      if (expectedMove.lengthSquared() > physics.getEpsilon()) {
        expectedMove.normalize();
        expectedMove.scale(actualDist);
        position.add(expectedMove);
      }
      remainingDist -= actualDist;
      if (remainingDist < physics.getEpsilon()) {
        break;
      }
      if (callback.hasHit()) {
        float originalSlope = callback.getHitNormalWorld().dot(new Vector3f(0, 1, 0));
        if (originalSlope < slopeFactor) {
          float slope = callback.calculateAverageSlope(originalSlope, CHECK_FORWARD_DIST);
          if (slope < slopeFactor) {
            remainingDist -= actualDist;
            expectedMove.set(targetPos);
            expectedMove.sub(position);
            extractResidualMovement(callback.getHitNormalWorld(), expectedMove);
            float sqrDist = expectedMove.lengthSquared();
            if (sqrDist > physics.getEpsilon()) {
              expectedMove.normalize();
              if (expectedMove.dot(normalizedDir) <= 0.0f) {
                hit = true;
                break;
              }
            } else {
              hit = true;
              break;
            }
            if (expectedMove.y > -physics.getEpsilon()) {
              hit = true;
              break;
            }
            normalizedDir.set(expectedMove);
            expectedMove.scale(-remainingDist / expectedMove.y + HORIZONTAL_PENETRATION_LEEWAY);
            targetPos.set(position);
            targetPos.add(expectedMove);
          } else {
            hit = true;
            break;
          }
        } else {
          hit = true;
          break;
        }
      } else {
        break;
      }
    }
    if (iteration >= 10) {
      hit = true;
    }
    return hit;
  }