Whatdotcolor

From Compsci.ca Wiki

Also spelled whatdotcolour (Canadian spelling of colour), it is a Turing function which returns the colour of a specific pixel. Often used for collision detection, it is an easy solution when creating something using Turing graphics alone without external images being involved.

It's actually so important that there's a whatdotcolor Warrior mod.

Here's a quick example of a few basic graphics functions which uses whatdotcolour to check if the mouse is above a red circle. %%Example of whatdotcolour collision detection

%%By: Gandalf

setscreen ("graphics,offscreenonly")

var cx, cy, mx, my, mb : int

cx := maxx div 2

cy := maxy div 2

var circleColour : int := red

loop

   cls

   Draw.FillOval (cx, cy, 40, 40, circleColour)

   Mouse.Where (mx, my, mb)

   %if your mouse is above the circle and you click

   if whatdotcolour (mx, my) = circleColour and mb > 0 then

       %move the circle to the mouse coordinates

       cx := mx

       cy := my

   end if

   View.Update

end loop

An alternative of whatdotcolour collision detection in Turing is using Math.Distance.