ColorRunner/core/src/de/samdev/colorrunner/game/world/entities/MovingEntity.java

package de.samdev.colorrunner.game.world.entities;

import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.math.Rectangle;
import com.badlogic.gdx.math.Vector2;

import de.samdev.colorrunner.CRGame;
import de.samdev.colorrunner.game.world.CRGameWorld;

public abstract class MovingEntity extends CRGameEntity {
	public Vector2 velocity = new Vector2();

	public final static float EPSILON       = 1e-4f;
	public final static float EPSILON_TOUCH = 5e-4f;

	private boolean face_TOP_isTouching    = false;
	private boolean face_LEFT_isTouching   = false;
	private boolean face_BOTTOM_isTouching = false;
	private boolean face_RIGHT_isTouching  = false;

	public MovingEntity(CRGameWorld _owner, float width, float height) {
		this(_owner, 0, 0, width, height);
	}

	public MovingEntity(CRGameWorld _owner, float x, float y, float width, float height) {
		super(_owner, x, y, width, height);
	}

	protected boolean moveByX(float bx) {
		if (bx == 0) return false;

		boolean collided = false;

		Rectangle next = new Rectangle(bounds);

		next.x += bx;

		for (CRGameEntity ent : world.entities) {
			if (ent == this) continue;

			if (overlaps(next, ent.bounds) && ent.canCollide(true, this)) {

				if (overlaps(ent.bounds, bounds)) {
					Gdx.app.log("Collision", "Ignore in bounds collision [X]");
					continue;
				}

				if (bx < 0) { // LEFT
					float correction = (ent.bounds.x + ent.bounds.height) - next.x + EPSILON;

					next.x += correction;
					bx = next.x - bounds.x;

					if (bx >= 0) return true; // collision but no movement

					collided = true;
				} else { // RIGHT
					float correction = (next.x + next.height) - ent.bounds.x + EPSILON;

					next.x -= correction;
					bx = next.x - bounds.x;

					if (bx <= 0) return true; // collision but no movement

					collided = true;
				}
			}
		}

		bounds.x = next.x;
		return collided;
	}

	protected boolean moveByY(float by) {
		if (by == 0) return false;

		boolean collided = false;

		Rectangle next = new Rectangle(bounds);

		next.y += by;

		for (CRGameEntity ent : world.entities) {
			if (ent == this) continue;

			if (overlaps(next, ent.bounds) && ent.canCollide(true, this)) {

				if (overlaps(bounds, ent.bounds)) {
					Gdx.app.log("Collision", "Ignore in bounds collision [Y]");
					continue;
				}

				if (by < 0) { // DOWN
					float correction = (ent.bounds.y + ent.bounds.height) - next.y + EPSILON;

					next.y += correction;
					by = next.y - bounds.y;

					if (by >= 0) return true; // collision but no movement

					collided = true;
				} else { // UP
					float correction = (next.y + next.height) - ent.bounds.y + EPSILON;

					next.y -= correction;
					by = next.y - bounds.y;

					if (by <= 0) return true; // collision but no movement

					collided = true;
				}
			}
		}

		bounds.y = next.y;
		return collided;
	}

	protected boolean updateHitBox(float width, float height) {
		boolean succ_x = updateHitBoxWidth(width);
		if (CRGame.DEBUG && getFirstCollision() != null) Gdx.app.error("Collision", "Collision after updateHitBox [[Width]] - " + succ_x);

		boolean succ_y = updateHitBoxHeight(height);
		if (CRGame.DEBUG && getFirstCollision() != null) Gdx.app.error("Collision", "Collision after updateHitBox [[Height]] - " + succ_y);


		return succ_x && succ_y;
	}

	private boolean updateHitBoxWidth(float width) {
		Rectangle next = new Rectangle(bounds);

		float add = width - bounds.width;

		if (isTouching_LEFT() && ! isTouching_RIGHT()) {
			next.width += add;
		} else if (! isTouching_LEFT() && isTouching_RIGHT()) {
			next.width += add;
			next.x -= add;
			next.x -= EPSILON;
		} else {
			next.width += add;
			next.x -= add/2;
		}

		if (add < 0) {

			if (CRGame.DEBUG) {
				for (CRGameEntity ent2 : world.entities) {
					if (ent2 == this) continue;

					if (overlaps(next, ent2.bounds) && ent2.canCollide(false, this)) {
						Gdx.app.log("Entity Hitbox", "Expand failed X- || WTF");
						return false;
					}
				}
			}

			bounds.set(next);
			return true;
		} else {
			for (CRGameEntity ent : world.entities) {
				if (ent == this) continue;

				if (overlaps(ent.bounds, next) && ent.canCollide(false, this)) {

					if (overlaps(ent.bounds, bounds)) {
						Gdx.app.log("Collision", "Ignore in bounds collision on HB Expand [X]");
						continue;
					}

					if (ent.bounds.x > next.x) {
						next.x -= (next.x + next.width) - ent.bounds.x + EPSILON;

						for (CRGameEntity ent2 : world.entities) {
							if (ent2 == this) continue;

							if (overlaps(next, ent2.bounds) && ent2.canCollide(false, this)) {
								Gdx.app.log("Entity Hitbox", "Expand failed X+");
								return false;
							}
						}
					} else if (ent.bounds.x < next.x) {
						next.x += (ent.bounds.x + ent.bounds.width) - next.x + EPSILON;

						for (CRGameEntity ent2 : world.entities) {
							if (ent2 == this) continue;

							if (overlaps(next, ent2.bounds) && ent2.canCollide(false, this)) {
								Gdx.app.log("Entity Hitbox", "Expand failed X-");
								return false;
							}
						}
					}
				}
			}

			bounds.set(next);
			return true;
		}
	}

	private boolean updateHitBoxHeight(float height) {
		Rectangle next = new Rectangle(bounds);

		float add = height - bounds.height;

		if (isTouching_BOTTOM() && !isTouching_TOP()) {
			next.height += add;
		} else if (! isTouching_BOTTOM() && isTouching_TOP()) {
			next.height += add;
			next.y -= add;
			next.y -= EPSILON;
		} else {
			next.height += add;
			next.y -= add/2;
		}

		if (add < 0) {

			if (CRGame.DEBUG) {
				for (CRGameEntity ent2 : world.entities) {
					if (ent2 == this) continue;

					if (overlaps(next, ent2.bounds) && ent2.canCollide(false, this)) {
						Gdx.app.log("Entity Hitbox", "Expand failed Y- || WTF");
						return false;
					}
				}
			}

			bounds.set(next);
			return true;
		} else {
			for (CRGameEntity ent : world.entities) {
				if (ent == this) continue;

				if (overlaps(ent.bounds, next) && ent.canCollide(false, this)) {

					if (overlaps(ent.bounds, bounds)) {
						Gdx.app.log("Collision", "Ignore in bounds collision on HB Expand [Y]");
						continue;
					}

					if (ent.bounds.y > next.y) {
						next.y -= (next.y + next.height) - ent.bounds.y + EPSILON;

						for (CRGameEntity ent2 : world.entities) {
							if (ent2 == this) continue;

							if (overlaps(next, ent2.bounds) && ent2.canCollide(false, this)) {
								Gdx.app.log("Entity Hitbox", "Expand failed Y+");
								return false;
							}
						}
					} else if (ent.bounds.y < next.y) {
						next.y += (ent.bounds.y + ent.bounds.height) - next.y + EPSILON;

						for (CRGameEntity ent2 : world.entities) {
							if (ent2 == this) continue;

							if (overlaps(next, ent2.bounds) && ent2.canCollide(false, this)) {
								Gdx.app.log("Entity Hitbox", "Expand failed Y-");
								return false;
							}
						}
					}
				}
			}

			bounds.set(next);
			return true;
		}
	}

	private void updateTouchCollisions() {
		face_TOP_isTouching = false;
		face_LEFT_isTouching = false;
		face_BOTTOM_isTouching = false;
		face_RIGHT_isTouching = false;

		for (CRGameEntity ent : world.entities) {
			if (ent == this) continue;

			if (Math.abs((ent.bounds.y + ent.bounds.height) - bounds.y) < EPSILON_TOUCH && ent.bounds.x < (bounds.x + bounds.width) && (ent.bounds.x + ent.bounds.width) > bounds.x && ent.canCollide(false, this)) {
				face_BOTTOM_isTouching = true;
			}

			if (Math.abs((bounds.y + bounds.height) - ent.bounds.y) < EPSILON_TOUCH && ent.bounds.x < (bounds.x + bounds.width) && (ent.bounds.x + ent.bounds.width) > bounds.x && ent.canCollide(false, this)) {
				face_TOP_isTouching = true;
			}

			if (Math.abs((bounds.x + bounds.width) - ent.bounds.x) < EPSILON_TOUCH && ent.bounds.y < (bounds.y + bounds.height) && (ent.bounds.y + ent.bounds.height) > bounds.y && ent.canCollide(false, this)) {
				face_RIGHT_isTouching = true;
			}

			if (Math.abs((ent.bounds.x + ent.bounds.width) - bounds.x) < EPSILON_TOUCH && ent.bounds.y < (bounds.y + bounds.height) && (ent.bounds.y + ent.bounds.height) > bounds.y && ent.canCollide(false, this)) {
				face_LEFT_isTouching = true;
			}
		}

	}

	public Vector2 getVelocity() {
		return velocity;
	}

	@Override
	public void update(float delta) {
		if (velocity.x != 0) {
			if (moveByX(velocity.x * delta)) {
				velocity.x = 0;
			}
			if (CRGame.DEBUG && getFirstCollision() != null) Gdx.app.error("Collision", "Collision after move [[X]]");
		}

		if (velocity.y != 0) {
			if (moveByY(velocity.y * delta)) {
				velocity.y = 0;
			}
			if (CRGame.DEBUG && getFirstCollision() != null) Gdx.app.error("Collision", "Collision after move [[Y]]");
		}

		updateTouchCollisions();
	}

	private CRGameEntity getFirstCollision()
	{
		for (CRGameEntity ent : world.entities) {
			if (ent == this) continue;
			if (overlaps(ent.bounds, bounds) && ent.canCollide(false, this)) return ent;
		}
		return null;
	}

	private boolean overlaps (Rectangle r1, Rectangle r2) {
		return r1.overlaps(r2) && r2.overlaps(r1); // make overlaps commutative (?)
	}

	public boolean isTouching_ANY() {
		return face_TOP_isTouching || face_LEFT_isTouching || face_BOTTOM_isTouching || face_RIGHT_isTouching;
	}

	public boolean isTouching_TOP() {
		return face_TOP_isTouching;
	}

	public boolean isTouching_LEFT() {
		return face_LEFT_isTouching;
	}

	public boolean isTouching_BOTTOM() {
		return face_BOTTOM_isTouching;
	}

	public boolean isTouching_RIGHT() {
		return face_RIGHT_isTouching;
	}
}