CameraControllingEntity

Introduction

The CameraControllingEntity is an object which provides convenient camera positioning and zooming functionality. It is included by default in the Top Down and Platformer projects when using the New Project Wizard.

Target

The Target property controls the desired location of the CameraControllingEntity. If a Target is assigned, the CameraControllingEntity changes its position to move towards the target according to the other properties assigned such as the Map and TargetApproachStyle.

Target can be assigned in code to change the desired position. The following code shows how to change between two targets by pressing the 1 and 2 keys on the keyboard:

void CustomActivity(bool firstTimeCalled)
{
    var keyboard = InputManager.Keyboard;
    if(keyboard.KeyPushed(Microsoft.Xna.Framework.Input.Keys.D1))
    {
        CameraControllingEntityInstance.Target = TargetEntity1;
    }
    else if(keyboard.KeyPushed(Microsoft.Xna.Framework.Input.Keys.D2))
    {
        CameraControllingEntityInstance.Target = TargetEntity2;
    }
}

Switching Targets with key presses

Targets

The Targets property (plural of Target) can be used to give the CameraControllingEntity multiple targets. This is typically used when the camera should follow a list of players in a mutiplayer game. The following code can be used to switch between following one of two targets individually or the list of targets. Notice that the CameraControllingEntity is positioned so that both targets are visible using their average X and Y values.

void CustomActivity(bool firstTimeCalled)
{
    var keyboard = InputManager.Keyboard;
    if(keyboard.KeyPushed(Microsoft.Xna.Framework.Input.Keys.D1))
    {
        CameraControllingEntityInstance.Target = TargetEntity1;
    }
    else if(keyboard.KeyPushed(Microsoft.Xna.Framework.Input.Keys.D2))
    {
        CameraControllingEntityInstance.Target = TargetEntity2;
    }
    else if(keyboard.KeyPushed(Microsoft.Xna.Framework.Input.Keys.D3))
    {
        // TargetEntityList contains both TargetEntity1 and TargetEntity2
        CameraControllingEntityInstance.Targets = TargetEntityList;
    }
}

CameraControllingEntity moving between individual targets and the list

Moving Immediately to the Target

By default the CameraControllingEntity interpolates from its current position to the target. This is normally desired as it can make the camera move smoothly. At times the Camera may need to be moved immediately to its target.

The following code results in the CameraControllingEntity moving immediately.

var target = CameraControllingEntityInstance.GetTarget();
// If true, the camera controlling entity will interpolate to its target
// position. If false, the camera controlling entity sets its position immediately.
var lerpSmooth = false;
CameraControllingEntityInstance.ApplyTarget(target, lerpSmooth);

Keep in mind that setting the Camera.Main's position to the target location will not immediately move the camera to the target position. If using a CameraControllingEntity, then the Camera's position becomes read only, so any changes to the camera position must be done through the CameraControllingEntity.

Additionally, when calling ApplyTarget, the value that is passed in should be obtained from the GetTarget method. The GetTarget method considers the bounds of the Map and the Camera size. Setting a value explicitly (such as by defining a Vector2 with constant X and Y values) may result in the CameraControllingEntity temporarily showing a region that is outside of the Map bounds.