We Keep Coding

SFML - C# Garbage Collector deletes object which is in use

I'm using SFML for C#. I want to create a BackgroundImage Sprite and then start drawing it with an Agent, represented as a Circle, on top of it like that:
static void Main(string[] args)
{
Window = new RenderWindow(new VideoMode((uint)map.Size.X * 30, (uint)map.Size.Y * 30), map.Name + " - MAZE", Styles.Default);
while (Window.IsOpen)
{
Update();
}
}
static public RenderWindow Window { get; private set; }
static Map map = new Map(string.Format(#"C:\Users\{0}\Desktop\Maze.png", Environment.UserName));
static public void Update()
{
Window.Clear(Color.Blue);
DrawBackground();
DrawAgent();
Window.Display();
}
static void DrawAgent()
{
using (CircleShape tempCircle = new CircleShape
{
FillColor = Color.Cyan,
Radius = 15,
Position = new Vector2f(30, 30),
Origin = new Vector2f(30, 30),
Scale = new Vector2f(.5f, .5f)
})
{
Window.Draw(tempCircle);
}
}
static private Sprite BackgroundImage { get; set; }
static void DrawBackground()
{
if (BackgroundImage == null)
BackgroundImage = GetBackground();
Window.Draw(BackgroundImage);
}
static Sprite GetBackground()
{
RenderTexture render = new RenderTexture((uint)map.Size.X * 30, (uint)map.Size.Y * 30);
foreach (var point in map.Grid.Points)
{
RectangleShape pointShape = new RectangleShape(new Vector2f(30, 30));
switch (point.PointType)
{
case PointType.Walkable:
pointShape.FillColor = Color.White;
break;
case PointType.NotWalkable:
pointShape.FillColor = Color.Black;
break;
case PointType.Start:
pointShape.FillColor = Color.Red;
break;
case PointType.Exit:
pointShape.FillColor = Color.Blue;
break;
}
pointShape.Position = new Vector2f(point.Position.X * 30, point.Position.Y * 30);
render.Draw(pointShape);
}
Sprite result = new Sprite(render.Texture);
result.Origin = new Vector2f(0, result.GetLocalBounds().Height);
result.Scale = new Vector2f(1, -1);
return result;
}
Everything works as intended when I start it, but after a few seconds, around the time when process memory reaches 70MB, BackgroundImage turns into completely white sprite. If I change the type of BackgroundImage and GetBackground() to RenderTexture, return "render" object and then change DrawBackground() function like this
void RenderBackground()
{
if (BackgroundImage == null)
BackgroundImage = GetBackground();
using (Sprite result = new Sprite(BackgroundImage.Texture))
{
result.Origin = new Vector2f(0, result.GetLocalBounds().Height);
result.Scale = new Vector2f(1, -1);
Window.Draw(result);
}
}
then the background sprite doesn't turn white, but storing entire RenderTexture, instead of Sprite and then constantly creating new Sprite objects every time we call RenderBackground() function seems like a bad idea.
Is there any way for GetBackground() function to return a Sprite which won't turn white once the function's local "render" variable is destroyed?

You're not completely off with your assumptions. Simplified, SFML knows two types of resources:
Light resources are small objects that are quick to create and destroy. It's not that bad to just drop them and recreate them later. Typical examples would be Sprite, Sound, Text, and basically most SFML classes.
Heavy resourcces are often big objects or objects requiring file access to create or use. Typical examples would be Image, Texture, SoundBuffer, and Font. You shouldn't recreate these and instead keep them alive while you need them. If they're disposed too early, light resources using them will fail in some way or another.
A sprite's texture turning white is – as you've discovered – a typical sign of the assigned texture being freed/disposed.
There are many different approaches to this, but I'd suggest you create some kind of simple resource manager that will load resources just in time or just return them, if they're loaded already.
I haven't used SFML with C# and I haven't really touched C# for quite a while, but for a simple implementation you'd just have a Dictionary<string, Texture>. When you want to load a texture file like texture.png, you look whether there's a dictionary entry with that key name. If there is, just return it. If there isn't, create the new entry and load the texture, then return it.
I'm out of practice, so please consider this pseudo code!
private Dictionary<string, Texture> mTextureCache; // initialized in constructor
public Texture getTexture(file) {
Texture tex;
if (mTextureCache.TryGetValue(file, out tex))
return tex;
tex = new Texture(file);
mTextureCache.add(file, tex);
return tex;
}
// Somewhere else in your code:
Sprite character = new Sprite(getTexture("myCharacter.png"));
If your heavy resource is a RenderTexture, you just have to ensure that it stays alive as long as it's used (e.g. as a separate member).

It turned out the answer was simpler that I expected. All I had to to was create new Texture object and then make a Sprite out of it. So instead of
Sprite result = new Sprite(render.Texture);
I wrote
Sprite result = new Sprite(new Texture(render.Texture));
Now garbage collector doesn't dispose Sprite's texture

UI text is not rendered but appearing in hierarchy — what is missing?

trying to show text dynamically created to the canvas but its not rendering.
After creating canvas an empty gameObject attached as child and the following script is attached to that. After running the object appears in hierarchy but not rendered.maybe I'm missing something:
GameObject o;
void Start() {
GameObject test = new GameObject("myTextGO");
test.transform.SetParent(this.transform);
// test.transform.SetParent(o.transform);
Text myText = test.AddComponent<Text>();
myText.text = "Hello there!";
}
Also tried few other combination but not text is not rendering. Need to know solution.

Three things required to do when creating UI text dynamically and manually:
Font
Proper Parenting
RectTransform (Now, automatically attached by Unity when UI component
is attached to a GameObject)
I assume that you are using the latest Unity version so you just need to do the first two:
Supply font for the Text component to use as mentioned this answer. Also, when using transform.SetParent, you have to supply false to it. This causes the UI component to keep its local orientation.
void CreateText(GameObject canvas, string text)
{
//Create Canvas Text and make it child of the Canvas
GameObject txtObj = new GameObject("myTextGO");
txtObj.transform.SetParent(canvas.transform, false);
//Attach Text,RectTransform, an put Font to it
Text txt = txtObj.AddComponent<Text>();
txt.text = text;
Font arialFont = Resources.GetBuiltinResource<Font>("Arial.ttf");
txt.font = arialFont;
txt.lineSpacing = 1;
txt.color = new Color(50 / 255, 50 / 255, 50 / 255, 255 / 255);
}
Usage:
public GameObject canvas;
void Start()
{
CreateText(canvas, "Hello there!");
}
That's how to create a text component manually but that should no longer be used. Let Unity do this automatically. The DefaultControls should be used to create UI Objects. It reduces the chances that the creation code will fail or that you'll run into similar issues in your question. Create the Text resources with DefaultControls.Resources then the Text itself with DefaultControls.CreateText.
void CreateText(GameObject canvas, string text)
{
DefaultControls.Resources uiResources = new DefaultControls.Resources();
GameObject uiText = DefaultControls.CreateText(uiResources);
uiText.transform.SetParent(canvas.transform, false);
uiText.GetComponent<Text>().text = text;
//Change the Text position?
//uiText.GetComponent<RectTransform>().sizeDelta = new Vector2(100f, 100f);
}

There is no font attached to the Text-object.
Try adding this line
myText.font = Resources.GetBuiltinResource<Font>("Arial.ttf");

Disable script outside of the scene Unity 3D

In my chess game, I have a scene of pieces choice - black or white. After the user clicks on one of the pawns he/she gets a popup message/ It looks like this:
On Ok button click, the scene changes to the one with the board:
When the user chose black pieces he/she should see them closer to him/her, while if the user chose white pieces, they should be at the front. By default, in my scene pieces which are closer are black. I tried to achieve this by adding a texture change script on each figure (they will differ for white and black pieces):
void Start () {
GetComponent<Renderer>().material = Resources.Load<Material>)"Materials/Pieces/Marble/White Pawn");
}
However, how can I disable this script when I redirect to the scene if the user chose black pieces and the default view is needed.
Here is my code for popup window:
void OnGUI()
{
if (showPopUp)
{
GUI.Window(0, new Rect((Screen.width / 2) - 200, (Screen.height / 2) - 115
, 420, 180), ShowGUI, "Figures choice");
}
}
void ShowGUI(int windowID)
{
RedirectToMenu redirect = new RedirectToMenu();
guiStyle.fontSize = 22;
guiStyle.normal.textColor = Color.white;
GUI.Label(new Rect(80, 40, 200, 30), "You have chosen black pieces", guiStyle);
if (GUI.Button(new Rect(180, 110, 75, 35), "OK")){
showPopUp = false;
redirect.LoadAsset("UpgradedRoom");
SceneManager.LoadScene("UpgradedRoom");
}
}
I suppose I should access this script before loading the scene and disable if needed. But how can I access it outside of the scene with table, chessboard, and pieces? Or can I change the textures of game objects on another scene?

What I would do is use a static variable to remember whether the pieces are black or white. So, you'd set the variable before the scene loads and then check it after it is loaded. Therefore, if your class is called chess manager, your code for setting the variable might look like this:
public class ChessManager : Monobehavior {
public enum ChessColor { Black, White }
public static ChessColor playerColor
public void OnGUI() {
if(user chooses black) {
playerColor = ChessColor.Black;
//Load scene
}
else if(user chooses white) {
playerColor = ChessColor.White;
//Load scene
}
}
}
...And your code for enabling/disabling the script might be something like this, where ColorChanger is the script that sets the color:
public class ColorChanger : Monobehavior {
public void Start() {
if(ChessManager.playerColor == ChessManager.ChessColor.White) {
//Set texture
}
}
}
This would set the texture to something else when the user chooses white once the new scene is loaded. Don't forget to replace the if statements in ChessManager with the code that executes when a chess piece is selected (I'm assuming you're using legacy buttons for that, so you should replace if(user chooses color) with if(GUI.Button)). Hope I could help!
Also, as previously noted by someone else in the comments, it would probably be best if you used UnityEngine.UI instead of Unity's outdated legacy GUI system, but depending upon the project it might not be worth the effort.

How to create a smooth animated text marquee?

I know that there are lot of different threads about horizontal text animation/text scrolling, but unfortunately none of them give smooth scrolling with repeatable text. I have tried double/thickness animation using various WPF controls containing text. Also tried animating with visual brush which gives me by far the most elegant scrolling compared to other approaches (for e.g. playing with Canvas.Left property etc.) but that too goes blur the text, if the text length or the animation speed is too high.
I'm over to a pure DirectX C# implementation using SharpDX library. Should also mention that I'm a beginner with DirectX programming. Here is the code:
public void RunMethod()
{
// Make window active and hide mouse cursor.
window.PointerCursor = null;
window.Activate();
var str = "This is an example of a moving TextLayout object with no snapped pixel boundaries.";
// Infinite loop to prevent the application from exiting.
while (true)
{
// Dispatch all pending events in the queue.
window.Dispatcher.ProcessEvents(CoreProcessEventsOption.ProcessAllIfPresent);
// Quit if the users presses Escape key.
if (window.GetAsyncKeyState(VirtualKey.Escape) == CoreVirtualKeyStates.Down)
{
return;
}
// Set the Direct2D drawing target.
d2dContext.Target = d2dTarget;
// Clear the target.
d2dContext.BeginDraw();
d2dContext.Clear(Color.CornflowerBlue);
//float layoutXOffset = 0;
float layoutXOffset = layoutX;
// Create the DirectWrite factory objet.
SharpDX.DirectWrite.Factory fontFactory = new SharpDX.DirectWrite.Factory();
// Create a TextFormat object that will use the Segoe UI font with a size of 24 DIPs.
textFormat = new TextFormat(fontFactory, "Verdana", 100.0f);
textLayout2 = new TextLayout(fontFactory, str, textFormat, 2000.0f, 100.0f);
// Draw moving text without pixel snapping, thus giving a smoother movement.
// d2dContext.FillRectangle(new RectangleF(layoutXOffset, 1000, 1000, 100), backgroundBrush);
d2dContext.DrawTextLayout(new Vector2(layoutXOffset, 0), textLayout2, textBrush, DrawTextOptions.NoSnap);
d2dContext.EndDraw();
//var character = str.Substring(0, 1);
//str = str.Remove(0, 1);
//str += character;
layoutX -= 3.0f;
if (layoutX <= -1000)
{
layoutX = 0;
}
// Present the current buffer to the screen.
swapChain.Present(1, PresentFlags.None);
}
}
Basically it creates an endless loop and subtracts the horizontal offset. Here are the challenges: I need repeatable text similar to HTML marquee without any gaps, Would probably need to extend it to multiple monitors.
Please suggest.

I don't know neither how to use DirectX nor sharpdx, but if you want you can consider this solution
I had a similar problem a while ago, but with the text inside a combobox. After a bounty i got what i was looking for. I'm posting the relevant piece of code as an example, but you can check the complete answer here
Basically, whenever you have a textblock/textbox that contain a string that cannot be displayed completely, cause the length exceed the textblock/box lenght you can use this kind of approach. You can define a custom usercontrol derived from the base you need (e.g. SlidingComboBox : Combobox) and define an animation for you storyboard like the following
_animation = new DoubleAnimation()
{
From = 0,
RepeatBehavior = SlideForever ? RepeatBehavior.Forever : new RepeatBehavior(1), //repeat only if slide-forever is true
AutoReverse = SlideForever
};
In my example i wanted this behaviour to be active only when the mouse was on the combobox, so in my custom OnMouse enter i had this piece of code
if (_parent.ActualWidth < textBlock.ActualWidth)
{
_animation.Duration = TimeSpan.FromMilliseconds(((int)textBlock.Text?.Length * 100));
_animation.To = _parent.ActualWidth - textBlock.ActualWidth;
_storyBoard.Begin(textBlock);
}
Where _parent represent the container of the selected item. After a check on the text lenght vs combobox lenght i start the animation and end it at the end of the text to be displayed
Note that in the question i mentioned there are also other soltions. I'm posting the one that worked for me

Xamarin - iOS Multiple polygons on map

I am currently following this tutorial for adding a polygon to a map. I need to be able to add multiple polygons to my map, so I have slightly altered the code so that I can use addOverlays which takes in an array of IMKOverlay objects instead of one addOverlay which just takes in a single IMKOverlay object.
This doesn't work however... It only draws the first polygon on the map!
void addPolygonsToMap()
{
overlayList = new List<IMKOverlay>();
for (int i = 0; i < polygons.Count; i++)
{
CLLocationCoordinate2D[] coords = new CLLocationCoordinate2D[polygons[i].Count];
int index=0;
foreach (var position in polygons[i])
{
coords[index] = new CLLocationCoordinate2D(position.Latitude, position.Longitude);
index++;
}
var blockOverlay = MKPolygon.FromCoordinates(coords);
overlayList.Add(blockOverlay);
}
IMKOverlay[] imko = overlayList.ToArray();
nativeMap.AddOverlays(imko);
}
In this discussion, it would appear that I have to call a new instance of MKPolygonRenderer each time I need to add another polygon to my map, but I'm unsure how this example translates to my code. Here is my MKPolygonRenderer function:
MKOverlayRenderer GetOverlayRenderer(MKMapView mapView, IMKOverlay overlayWrapper)
{
if (polygonRenderer == null && !Equals(overlayWrapper, null)) {
var overlay = Runtime.GetNSObject(overlayWrapper.Handle) as IMKOverlay;
polygonRenderer = new MKPolygonRenderer(overlay as MKPolygon) {
FillColor = UIColor.Red,
StrokeColor = UIColor.Blue,
Alpha = 0.4f,
LineWidth = 9
};
}
return polygonRenderer;
}

Create a new renderer instance each time OverlayRenderer is called, there is no need to cache the renderer in a class level variable as the MKMapView will cache the renderers as needed.
Subclass MKMapViewDelegate:
class MyMapDelegate : MKMapViewDelegate
{
public override MKOverlayRenderer OverlayRenderer(MKMapView mapView, IMKOverlay overlay)
{
switch (overlay)
{
case MKPolygon polygon:
var prenderer = new MKPolygonRenderer(polygon)
{
FillColor = UIColor.Red,
StrokeColor = UIColor.Blue,
Alpha = 0.4f,
LineWidth = 9
};
return prenderer;
default:
throw new Exception($"Not supported: {overlay.GetType()}");
}
}
}
Instance and assign the delegate to your map:
mapDelegate = new MyMapDelegate();
map.Delegate = mapDelegate;
Note: Store the instance of your MyMapDelegate in a class level variable as you do not want to get GC'd
Update:
MKMapView has two steps involved to display an overlay on its map.
1. Calling `AddOverlay` and `AddOverlays`
First you add overlays to the map that conform to IMKOverlay. There are basic built-in types such as MKCircle, MKPolygon, etc... but you can also design your own overlays; i.e. overlays that define the location of severe weather (lightning, storm clouds, tornados, etc..). These MKOverlays describe the geo-location of the item but not how to draw it.
2. Responding to `OverlayRenderer` requests
When the display area of the map intersects with one of the overlays, the map need to draw it on the screen. The map's delegate (your MKMapViewDelegate subclass) is called to supply a MKOverlayRenderer that defines the drawing routines to paint the overlay on the map.
This drawing involves converting the geo-coordinates of the overlay to local display coordinates (helper methods are available) using Core Graphics routines (UIKit can be used with some limitations). There are basic built-in renderers for MKCircleRenderer, MKPolygonRenderer, etc.. that can be used or you can write your own MKOverlayRenderer subclass.
You could supply a custom way to renderer a MKCircle overlay, maybe a target-style red/white multi-ringed bullseye, instead of the way the default circle renderer draws it, or custom renderers that draw severe storm symbols within the bounds of a MKPolygon to match your custom severe storm overlays.
My Example code:
Since you are using MKPolygon to build your overlays, you can use the MKPolygonRenderer to display them. In my example, I provide a pattern matching switch (C# 6) that returns a semi-transparent Red/Blue MKPolygonRenderer for every MKPolygon that you added to the map (if you added a non-MKPolygon based overlay it will throw an exception).

I was also stuck in this issue and I have found the way to create the sub class of MKPolygon.
I have checked it with my example and it works like a charm. But not sure that Apple may reject my app or not.
public class CvPolyon : MKPolygon
{
public CustomObject BoundaryOption { get; }
public CvPolyon1(MKPolygon polygon, CustomObject boundaryOption)
:base(polygon.Handle)
{
BoundaryOption = boundaryOption;
}
}
We can add polygon on map like this.
var polygon = MKPolygon.FromCoordinates(coordinates);
var overlay = new CvPolyon(polygon, new CustomObject());
mapView.AddOverlay(overlay);
We can recognize our polygon in the class which extends MKMapViewDelegate like this.
public override MKOverlayRenderer OverlayRenderer(MKMapView mapView, IMKOverlay overlay)
{
if (overlay is CvPolyon polygon)
{
var polygonRenderer = new MKPolygonRenderer(polygon)
{
FillColor = polygon.BoundaryOption.AreaColor,
StrokeColor = polygon.BoundaryOption.LineColor,
Alpha = polygon.BoundaryOption.Alpha,
LineWidth = polygon.BoundaryOption.LineWidth
};
if (polygon.BoundaryOption.IsDashedLine)
polygonRenderer.LineDashPattern = new[] { new NSNumber(2), new NSNumber(5) };
return polygonRenderer;
}
return mapView.RendererForOverlay(overlay);
}