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Select Area of Image in C# Monogame

Im migrating my game from Pygame to Monogame. I'm having trouble to create a Texture2D based on a cut of another big image. I have one picture with all my assets and i want to create diferent Textures for each one and saved them in memory like a bufffer. image

I tried this

Texture2D sprite = new Texture2D(game.Get_GraphicsDevice(), width, height);
                Color[] data = new Color [width * height];
                Texture2D sheet = texture;
                sheet.GetData(0, new Microsoft.Xna.Framework.Rectangle(x, y, width, height), data, 0, data.Length);
                sprite.SetData(data);

but im getting this code error System.ArgumentException: 'Type T is of an invalid size for the format of this texture. (Parameter 'T')''

Solution

  • This is not the best way to do this as you will have tons of texture switches which then lead to seperate draw calls for each sprite (FPS killer). I assume you're going to draw your sprites with SpriteBatch, which actually can draw a part of a texture (also with the Rectangle struct).

    Best course of action would be to create a simple custom sprite class, where you have fields or properties for the position and width/height in the big texture (yout atlas) or even better, a Rectangle struct and then use e.g. this function of SpriteBatch:

    public void Draw(Texture2D texture, Vector2 position, Rectangle? sourceRectangle, Color color) {...}

    Typically, you would then keep those 'Sprites' in a Dictionary or Array to access them later with your game objects or entities.

    This way, as long as they share the same texture, all your sprites will be drawn in a single draw call by SpriteBatch's internal batching system. So your starting point, working with a bigger atlas, is actually much better. Of course, several big texture atlases are also no problem.