Introduction
The TopDestination, BottomDestination, LeftDestination, and RightDestination properties of the LayerCameraSettings class allow Layers to render to only a portion of the Screen (also known as creating a mask). These coordinates are measured in pixel units in screen space. In other words, 0 is the left side of the screen for LeftDestination and RightDestination, and it increases to the right. The value of 0 is the top of the screen for TopDestination and BottomDestination, and it increases downward.
The destination values are not necessarily used when a given Layer is rendered. The default value for TopDestination, BottomDestination, LeftDestination, and RightDestination is -1. If -1 is used, then the Camera’s DestinationRectangle values are used.
Code Example
The following code creates a LayerCameraSetting which has a 200 pixel border around the edges of the screen. The Layer draws a large Sprite which is masked by the destination values of the LayerCameraSettings.
Add the following using statement:
using FlatRedBall.Graphics;
Add the following to Initialize after initializing FlatRedBall:
// Make sure the camera is in 3D:
SpriteManager.Camera.Orthogonal = false;
// Create a new Layer
Layer layer = SpriteManager.AddLayer();
// Create a LayerCameraSettings
LayerCameraSettings layerCameraSettings = new LayerCameraSettings();
layerCameraSettings.Orthogonal = true;
layerCameraSettings.TopDestination = 200;
layerCameraSettings.BottomDestination = 400;
layerCameraSettings.LeftDestination = 200;
layerCameraSettings.RightDestination = 600;
layerCameraSettings.OrthogonalWidth = layerCameraSettings.RightDestination - layerCameraSettings.LeftDestination;
layerCameraSettings.OrthogonalHeight = layerCameraSettings.BottomDestination - layerCameraSettings.TopDestination;
layer.LayerCameraSettings = layerCameraSettings;
// Now the Layer will draw in 2D. Let's make a Sprite:
Sprite sprite = SpriteManager.AddSprite("redball.bmp");
sprite.ScaleX = 400;
sprite.ScaleY = 400;
SpriteManager.AddToLayer(sprite, layer);
Exceptions related to display size
If you are explicitly setting the destination rectangle of a LayerCameraSettings object, then you may encounter an exception. If FlatRedBall detects that the BottomDestination is too large, you may get an error as follows:
The pixel height resolution of the display is 590 but the LayerCameraSetting's BottomDestination is 600
Similarly you may get a message about the width, which might read:
The pixel width resolution of the display is 790 but the LayerCameraSetting's RightDestination is 800
You can fix this in one of the following ways:
- Prevent resizing of your game window
- Adjust the LayerCameraSettings for your Layer to fit within the bounds of the display
- Set the LayerCameraSettings’ destination values to -1, which will result it in automatically adjusting to its contained Camera destination.