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I am having trouble reading a spritesheet with rows and columns. If it is just one row, then my code works fine. The sheet looks like this:

enter image description here

Source: Character animations, clothes, armor, weapons, skeleton enemy, combat dummy

Right now, it only works with the first row. I can't figure out how to move it down to the next row. I know I have to change my SourceRect for the x and y but don't know to what.

Here's my code:

class SpriteSheet
{
    public Texture2D Texture { get; set; }
    public Vector2 Origin { get; set; }
    public Rectangle SourceRect { get; set; }
    public Vector2 position;

    private float timer, interval;
    private int currentFrame;
    private int spriteWidth, spriteHeight, spriteSpeed;
    private int rows, columns;
    private KeyboardState currentKBState, previousKBState;

    public SpriteSheet(Texture2D texture, int spriteWidth, int spriteHeight, int rows = 1, int columns = 0, int currentFrame = 1)
    {
        Texture = texture;
        this.currentFrame = currentFrame;
        this.spriteWidth = spriteWidth;
        this.spriteHeight = spriteHeight;
        this.rows = rows;
        this.columns = columns;

        spriteSpeed = 100;
        interval = 200;
    }

    // Handle movement of sprite
    public void Update(GameTime gameTime)
    {
        previousKBState = currentKBState;
        currentKBState = Keyboard.GetState();

        // Get the sprite from the sheet
        // THIS LINE NEEDS TO BE CHANGED I THINK
        SourceRect = new Rectangle(currentFrame * spriteWidth, 0, spriteWidth, spriteHeight);

        if(currentKBState.GetPressedKeys().Length == 0)
        {
            if (currentFrame > 0 && currentFrame < 9)
                currentFrame = 0;

            if (currentFrame > 9 && currentFrame < 18)
                currentFrame = 9;

            if (currentFrame > 18 && currentFrame < 27)
                currentFrame = 18;

            if (currentFrame > 27 && currentFrame < 36)
                currentFrame = 27;
        }

        // Animate Up
        if (currentKBState.IsKeyDown(Keys.Up))
        {
            AnimateUp(gameTime);

            // Check boundary
            if (position.Y > 25)
                position.Y -= (float) (spriteSpeed * gameTime.ElapsedGameTime.TotalSeconds);
        }
    }

    private void AnimateUp(GameTime gameTime)
    {
        if (currentKBState != previousKBState)
            currentFrame = 1;

        timer += (float)gameTime.ElapsedGameTime.TotalMilliseconds;

        if(timer > interval)
        {
            currentFrame++;
            if (currentFrame > 8)
                currentFrame = 0;

            timer = 0f;
        }
    }
}
share|improve this question
    
You keep Y at a constant 0. That parameter should (judging by the spritesheet) be set to a value corresponding to the direction your character is moving. – Felsir yesterday
up vote 4 down vote

Your y-coordinate is always 0, so only the first row is used. You need to change this line:

SourceRect = new Rectangle(currentFrame * spriteWidth, 0, spriteWidth, spriteHeight);

into something like this (see the second parameter):

SourceRect = new Rectangle(currentFrame * spriteWidth, wantedRow * spriteHeight, spriteWidth, spriteHeight);
share|improve this answer
    
Thanks for the reply; unfortunately, the sprite doesn't show up no matter what row I put for wantedRow. I did figure it out in another way but had to change some of the code. – m.o 21 hours ago
up vote 0 down vote

So I changed up the code a bit to make it work:

Constructor change:

public SpriteSheet(Texture2D texture, int rows = 1, int columns = 0, int currentFrame = 0)
{
    this.texture = texture;
    this.sheetRows = rows;
    this.sheetColumns = columns;

    // Default = top left
    this.currentFrame = currentFrame;

    // Get a single sprite's width and height
    sheetWidth = texture.Width / sheetColumns;
    sheetHeight = texture.Height / sheetRows;
}

I noticed I didn't have to manually supply the width and height of the sprite and I could just get it from the sprite sheet. I handle the spriteSpeed and interval in my movement methods instead of the constructor now.

I removed the SourceRect line from the Update method and moved it to a custom Draw method:

public void Draw(SpriteBatch spriteBatch)
{
    // Get the correct frame
    spriteRow = currentFrame / sheetColumns;
    spriteColumn = currentFrame % sheetColumns;

    sourceRect = new Rectangle(sheetWidth * spriteColumn, sheetHeight * spriteRow, sheetWidth, sheetHeight);
    origin = new Vector2(sourceRect.Width / 2, sourceRect.Height / 2);

    spriteBatch.Draw(texture: texture, sourceRectangle: sourceRect, position: position, origin: origin, scale: new Vector2(1.0f));
}

Finally, getting the row and column of the sprite became easier with a little division.

If I wanted row 3 and column 1, the currentFrame would be 18. Knowing this, it was pretty straightforward to fix the part of the code where I reset the currentFrame where no keys are pressed.

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