Physics.java

import java.util.ArrayList;

public class Physics {
	private int speed;
	private double gravity;
	private double terminal;
	private double velocityX;
	private double velocityY;
	private double friction;

	public Physics (int speed) {
		this.speed = speed;
		this.gravity = 0.3;
		this.terminal = 8;
		this.velocityX = 0.0;
		this.velocityY = 0.0;
		this.friction = 0.8;
	}

	public void applyGravity() {
		if (velocityY < terminal) {
			velocityY += gravity;
		}
	}

	public void update(ArrayList<Block> blocks, Player player) {
		applyGravity();
		applyFriction();
		checkCollisions(blocks, player);
	}

	public double getVelocityX() {
		return this.velocityX;
	}

	public double getVelocityY() {
		return this.velocityY;
	}

	public void jump() {
		velocityY = -speed*2;
	}

	public void moveLeft() {
		if (velocityX > -speed ) {
			velocityX--;
		}
	}

	public void moveRight() {
		if (velocityX < speed ) {
			velocityX++;
		}
	}

	public void checkCollisions(ArrayList<Block> blocks, Player player) {
		for (Block block : blocks) {
			if (block.isTouching(player) ) {
				checkCollisionCeiling(block, player);
				checkCollisionFloor(block, player);
				checkCollisionRight(block, player);
				checkCollisionLeft(block, player);
			}
		}
	}

	public void checkCollisionFloor(Block block, Player player) {
		if (player.getY() < block.getY() && velocityY > 0 ) { //player higher than block & falling
			if ( block.isTouchingX(player, 0.5) ) {			  //ensure player and block on same column
				this.velocityY = 0;
				player.isJumping(false);
			}
		}
	}

	public void checkCollisionCeiling(Block block, Player player) {
		if (player.getY() > block.getY() && velocityY < 0) {	//player lower than block & jumping
			this.velocityY *= -0.5;
		}
	}

	public void checkCollisionRight(Block block, Player player) {
		if (player.getX() < block.getX() && velocityX > 0 ) {	//player left of block & moving right
			if ( block.isTouchingY(player, 0.5) ) {				// ensure player and block on same row
				this.velocityX *= -1;
			}
		}
	}

	public void checkCollisionLeft(Block block, Player player) {
		if (player.getX() > block.getX() && velocityX < 0 ) {	//player right of block & moving left
			if ( block.isTouchingY(player, 0.5) ) {				// ensure player and block on same row
				this.velocityX *= -1;
			}
		}
	}

	public void applyFriction() {
		velocityX *= friction;
	}
}