The game camera

Escoria uses an advanced camera system to allow different effects in a room.

It is possible to have rooms bigger than the selected display size, in which the camera will pan to always keep track of the player character. Additionally, you can use the camera for highlighting specific parts of the scene, zooming in and out, and more.

Camera limits

Usually the camera follows the player character as the character moves through the rooms. If the background is larger than the viewport, the camera will also pan the room to keep track of the player character.

Sometimes this behaviour is not desired, though. Some rooms are designed so that, at first, one part of the room is available to the player and, later, another part of the room becomes available.

Elevators are a good example: The player character starts at the ground floor, enters the elevator, and moves up. After the elevator leaves the screen, the view switches to a higher floor with the elevator opening.

To support limiting the parts of the room the player can see, Escoria rooms use “Camera Limits”. The limits are a list of rectangles which define the boundaries that the camera is allowed to move within. Each rectangle is defined using a top-left coordinate limit for the camera’s movement, along with an accompanying width and height. This array of limits is found under the Camera limits parameter within the room’s ESCRoom node.

The active limit rectangle for the camera can be changed during gameplay using the ASHES command camera_set_limits with the index of the camera limit to enforce.

If no camera limits are set, the size of the background texture is used as the default camera limit.

As only one limit is active at a time, limits can overlap. This means, for example, that if you had a large room with a locked door in the middle, you could have the initial limit as one half of the room, and the second limit - for when the door is unlocked - overlapping it as the whole room.

Camera control

There are various ASHES commands that can be used to control the camera to achieve theatrical effects:

• camera_push pushes the camera to point at the given target

• camera_set_pos moves the camera to the given position in a linear fashion

• camera_set_target sets the target that the camera should follow

• camera_set_zoom zooms the camera by the specified magnitude

• camera_set_zoom_height zooms the camera to achieve a certain pixel height

• camera_shift shifts the camera to the given location

All commands support a speed parameter that defines in seconds how long the camera animation should take to reach the target.

Hint

Some camera commands may not work as expected if you have camera limits defined. Ensure that the position the camera is told to point at is within the room’s active camera limit; e.g. if you were making a game using a resolution of 320 x 200, and your room limits were [100,100,1000,1000], the top left coordinate the camera could reach would be [420,300], while the bottom right coordinate it could reach would be [680,800].

Hint

The coordinates passed in to camera script commands refer to where the centre of the camera will point.

Targets

Commands that support a target object allow the following target types:

• An ESCItem that has set the parameter camera_node to a node whose position should be used to position the camera. If the parameter is not set, the position of the ESCItem is used instead.

• Vector2D: The target is a position described by the given vector.

• An array of Vector2D objects: The target is the average of all items of the array.

Follow targets must be nodes that have been set to be “movable”.

Transitions

Some commands support transtions. These can make use of different types of animation interpolations.

The transitions that are supported are the names of the values used in the TransitionType enum of the Tween type.

When specifying the TransitionType, leave off the TRANS_ prefix for any such parameters.