How do I invert the Y value?

Hi everyone, I'm tinkering with a game idea I had which is a vertically scrolling platformer.

The problem I'm having is trying to figure out how I should/could set the score value according to the height of which the player has gotten to as the Y-value starts at 0 at the top of the screen and increases downwards (i.e. the opposite of what I want) and also a way of normalising the scores since the Y-values I'm getting right now are the raw Y-values which are derived from the layout's height.

An example would be a game like http:// scirra .com/arcade/action/6344/piggy-jump but with a scoring element to it. Perhaps a 0-99 range for the first "screen" and a 100-199 range for the second "screen" and so on...

Would appreciate any tips or suggestions!

Player.Y * -1

Inverts the y value

200 * -1 = -200

-200 * -1 = 200

Thanks for your reply but that doesn't seem to work for me. The problem is, I'm not getting a negative value in the first place. I'm getting something like 1821 when it's at the bottom of the screen and it decreases as the player travels upwards.

EDIT: Doh! I've managed to answer my own question. I just had to subtract the heights of the player and the ground it is on to get the correct values. Thanks!

You can also use the abs expression to always get a positive value.

e.g. abs(-127) = 127

You can also use the abs expression to always get a positive value.

e.g. abs(-127) = 127

Yup. I'm using that now after stumbling upon it last night. Thanks anyway!