Calculating Window Coordinates -- glViewPort

I was reading OpenGL’s documentation for glViewPort and there was given a formula for how Window Coordinates are calculated in OpenGL.

This is the equation : - x[SUB]window[/SUB] = (x[sub]normalized[/sub] + 1) * (width / 2) + x

I’m a li’l bit confused, what if x[sub]normalized[/sub] = 1.0 ? Will the x[sub]window[/sub] go out of Screen’s Width?


x[sub]window[/sub] = (1 + 1) * (width / 2) + x;
x[sub]window[/sub] = 2 * (width/2) + x = width + x

(width being the width of the actual resolution of the Screen)

So, doesn’t it go out of the Screen? Somebody please clear this confusion.

No. Unless you set the viewport x position to a non zero value and/or a viewport width larger than the screen.

So, if you define this:


with a window with the same size (800x600), then xwindow max value can be width=800, which is perfect.
But if you do something like


Then for sure, you’ll exceed the physical window size.

Read this(maybe once again if the documentation you are referring to is the same).

Thank you for clearing the situation. : )