Messages

1

DotNet / Re: Updating texture of sprite.

« on: September 14, 2017, 03:05:24 pm »

Do you mean that this should work?

Thread thread = new Thread(delegate () {
        Monitor.Enter(w);
        //w.SetActive(true);

        tex.Update(imgB);

        //w.SetActive(false);
        Monitor.Exit(w);
});
thread.Start();

while (w.IsOpen) {
        w.DispatchEvents();

        Monitor.Enter(w);
        //w.SetActive(true);

        w.Clear(Color.White);
        w.Draw(spr1);
        w.Draw(spr2);
        w.Draw(spr3);
        w.Draw(spr4);

        //w.SetActive(false);
        Monitor.Exit(w);

        w.Display();
}    

If I run the program with the code like this, the textures won't update.

2

DotNet / Re: Updating texture of sprite.

« on: September 14, 2017, 02:51:38 pm »

I can confirm that the problem was related to calling the update-method in a separate thread. I adjusted my code as follows (full code in attachment):

Thread thread = new Thread(delegate () {
        Monitor.Enter(w);
        w.SetActive(true);

        tex.Update(imgB);

        w.SetActive(false);
        Monitor.Exit(w);
});
thread.Start();

while (w.IsOpen) {
        w.DispatchEvents();

        Monitor.Enter(w);
        w.SetActive(true);

        w.Clear(Color.White);
        w.Draw(spr1);
        w.Draw(spr2);
        w.Draw(spr3);
        w.Draw(spr4);

        w.SetActive(false);
        Monitor.Exit(w);

        w.Display();
}
 

Without the Monitor I got the 'Failed to activate the window's context'-message. I don't know whether this is the most elegant solution, but it seems to work without errors.

3

DotNet / Re: Updating texture of sprite.

« on: September 14, 2017, 12:38:56 pm »

Hi

I just tried the other update methods, but the result stayed the same.
However I did notice that when using the MouseButtonPressed-event instead of the Timer-event, it all seemed to work.

So now I am wondering: is it possible that the update-method from Texture fails when it is called from a thread that is not the main-thread? I can't recall having read about it in the documentation...

4

DotNet / Re: Updating texture of sprite.

« on: September 11, 2017, 09:49:45 am »

I just wrote the code to test this (see attachments). After 2 seconds, each blue 'A' image should change to the yellow 'B' image.

Note the commented line (r33). You can uncomment it to see the expected result.

I am using SFML.Net 2.2.0.0 64-bit.

5

DotNet / Re: Updating texture of sprite.

« on: September 10, 2017, 10:54:06 pm »

I double checked it and I can confirm the images are both the same size.

This is exactly what I do. While debugging I can clearly see that the if-test succeeds.
If I uncomment the last line, I works for a single Sprite, but I am looking for updating multiple Sprites at once (and this approach would be quite some overhead).

public MyClass : Sprite {
        private Image mImg;

        public MyClass() {
                mImg = new Image("ArrowRed.png");
               
                this.Texture = new Texture(mImg);
                this.TextureRect = new IntRect(0, 0, 32, 32);
        }

        public void OnAction() {
                Image newImg = new Image("ArrowGreen.png");

                if (mImg.Size == newImg.Size) {
                        this.Texture.Update(newImg);
                        //this.Texture = new Texture(newImg); (This one works obviously)
                }
        }
}
 

6

DotNet / Re: Updating texture of sprite.

« on: September 10, 2017, 10:05:03 pm »

I'll try to make it more clear .

Suppose I have an image of a cat and an image of a dog. First I load the image of the cat and assign it to the Texture 'my_texture'. Next, I create 10 instances of Sprite with this 'my_texture'.

At a certain moment in time, all the cats are at the exact same moment replaced by dogs. I load the image of the dog and use 'my_texture.Update(dog_image)' to update 'my_texture'. Because all of the 10 instances of Sprite have been created with the same Texture, and 'my_texture' has been updated with the dog image, I expected that all the Sprites would now show a dog, instead of a cat. However, the Sprites are still displaying the image of the cat.

So to wrap it up: I guessed that, because each Sprite keeps a pointer to its Texture, changing the Texture would change the image displayed by the Sprite. This does not seem to be the case. Should I invoke a method from Sprite to let it know the texture has changed?

7

DotNet / Updating texture of sprite.

« on: September 10, 2017, 09:05:11 pm »

Hi

I am trying to update the texture of a sprite by updating the current texture with a new image instead of assigning another texture to the sprite. See code below if it seems a bit vague. To bad for me, it does not seem to work. (Though maybe it is just because I am doing something wrong...)

In the official tutorials I have found the following quote (https://www.sfml-dev.org/tutorials/2.4/graphics-sprite.php) :

When you set the texture of a sprite, all it does internally is store a pointer to the texture instance. Therefore, if the texture is destroyed or moves elsewhere in memory, the sprite ends up with an invalid texture pointer.

   
As the quote states, a sprite holds a pointer to the texture it uses, so my idea would be that when the texture changes, the appearance of the sprite also changes. Of course this quote is targeting the C++-version, but i sort of expected that it would be the same for the .NET binding.

I do know that there a several ways around this problem, like creating an image that holds both the first and the second image so i just need to adjust the TextureRect, but I would like to know if there is any way to reach my goal as I am currently trying.

Thanks
     

class MyClass {
        private Image mImage;
        private Texture mTexture;

        public TextureHandlerClass() {
                mImage = new Image( /* image path */ );
                mTexture = new Texture(mImage);
                Sprite a = new Sprite(mTexture);
                Sprite b = new Sprite(mTexture);
                Sprite c = new Sprite(mTexture);
                Sprite d = new Sprite(mTexture);
        }

        private void ColorUpdate(object sender, EventArgs e) {
                mImage = new Image( /* other image path */ );
                mTexture.Update(mImage);
        }
}