Jumping & Sliding

Jumping

Jumping Motion

The player jumps directly upwards when the user presses either the 'W' or the 'SPACE' key. This is done by applying a force in the positive Y direction to the center of the player's body using the jump() function in the PlayerActions class. If the player is moving either to the left or right when jumping, the player will again jump upwards but continue to move in the desired direction, done so in the walk() function also located in the PlayerActions class. Put briefly, the player can move in both the X and Y directions at the same time.

Interaction with Collisions

The player should only be able to jump upwards when they are in contact with the ground, an obstacle, etc. This prevents the player from being able to fly through the level and complete the game without having to evade any obstacles. To implement this, the PlayerMovementComponent and JumpableComponent classes were created to track the player's collisions with different objects in the map. JumpableComponent is a dummy component that acts as an indicator to the onCollisionStart function in the PlayerMovementComponent class to whether the player should be able to jump off the object. onCollisionStart retrieves the two fixtures involved in the collision dependent upon the specified targetLayer (i.e. obstacle). This component should only be applied to player entities as the first fixture retrieved is the component's owner (i.e. me). It then gets the body data of both of the fixtures and, if the target fixture contains a PhysicsComponent and a JumpableComponent, calls togglePlayerJumping() of PlayerActions. This toggles the canJump variable of the player's actions and sets their PlayerState back to PlayerState.MOVING, thus allowing them to jump().

Sliding

Sliding Motion

The player slides left or right, dependent upon which direction the last moved in, when the user presses the 'SHIFT_RIGHT' key. This is done by applying a force in the positive or negative X direction to the center of the player's body using the slide() function in the PlayerActions class.

Dependency on Prior Movement

To make sure the player slides in the desired direction, the previousWalkDirection variable tracks the direction the player last moved in. This gets set by setPreviousWalkDirection() in PlayerActions through event handling. When the 'A' or 'D' keys are pressed, KeyboardPlayerInputComponent passes the relevant Vector2Util vector to the function and assigns it to previousWalkDirection. Then, slide() evaluates previousWalkDirection and applies the revelant force.