What Color Lies Under My Mouse?

1

Well…
Every language has it own complications, but I guess when we are now learning, some thing seem like rock.
I’m trying to get the color of the pixel under the mouse pointer. I have this so far:

        // retrieve the color of the pixel beneath the mouse
        Rectangle areaOfFocus = new Rectangle(mousex, mousey, 1, 1);
        Color[] pixelCol = new Color[iCol];
        imageFocus.GetData<Color>(0, areaOfFocus, pixelCol, 0, 1);

But how do I know what color it is, so that I can compare it to another?

2

I should probably be a bit more specific.
I know that pixelCol is the color, called a 1D color. I have seen it converted to a 2D, but I do not want it compared to a 1D, 2D, or 3D. I want to compare it to just color. For example, when I compare it to the background color -
if (pixelCol == backgroundCol)
or
if (pixelCol[] == backgroundCol)
or
if (pixelCol[…an integer…] == backgroundCol)
I get an error. I just want to be able to do that comparison ,without an error. It is here that I am totally clueless. Can anyone help, please?

3

You would compare with pixelCol[0]. What is the error you are getting?

4

The index 0 worked.
I was using an integer to represent the index, and got the message of index out of range.

      Rectangle areaOfFocus = new Rectangle(mousex, mousey, 1, 1);
      Color[] pixelCol = new Color[iCol];
      imageFocus.GetData<Color>(0, areaOfFocus, pixelCol, 0, 1);

im1.png720×448 39.8 KB

no error returns when I use 0, but nothing happens to my text.
if (pixelCol[0] == backgroundCol) { buttonInfo = “It Worked!”; }

Is this code correct?

    Boolean pixCheck = false;
    private string buttonInfo = "CLICK ME";

    protected override void Update(GameTime gameTime)
    {
        if (mousex > imageFocus.Width - imageFocus.Width && mousex < imageFocus.Width &&
          mousey > imageFocus.Height - imageFocus.Height && mousey < imageFocus.Height)
        {
            mousex = currentMouseState.X;
            mousey = currentMouseState.Y;

            // retrieve the color of the pixel beneath the mouse
            Rectangle areaOfFocus = new Rectangle(mousex, mousey, 1, 1);
            Color[] pixelCol = new Color[1];
            imageFocus.GetData<Color>(0, areaOfFocus, pixelCol, 0, 1);

            if (pixelCol[0] == backgroundCol) { buttonInfo = "It Worked!"; pixCheck = true; }
              else { buttonInfo = "CLICK ME"; pixCheck = false; }
        }
    }

    protected override void Draw(GameTime gameTime)
    {
        graphics.GraphicsDevice.Clear(backgroundCol);
        //GraphicsDevice.Clear(Color.Black); // start with a black background 

        if (pixCheck)
        {
            spriteBatch.Begin(SpriteSortMode.Deferred, BlendState.AlphaBlend);
            spriteBatch.DrawString(myButton_Font, buttonInfo, fontPos, Color.White, 0,
                                fontCenter, 1.0f, SpriteEffects.FlipHorizontally, 0f);
            spriteBatch.End();
        }
        else
        {
            spriteBatch.Begin(SpriteSortMode.Deferred, BlendState.AlphaBlend);
            spriteBatch.Draw(myButton_START, screenCenter, null, Color.White,
                                0, spriteCenter, 1.0f, SpriteEffects.None, 0.5f);

            spriteBatch.DrawString(myButton_Font, buttonInfo, fontPos, Color.YellowGreen, -9,
                                    fontCenter, 1.0f, SpriteEffects.FlipHorizontally, 0f);
            spriteBatch.End();

        }
        
        base.Draw(gameTime);
    }