CODEWITHSUNDEEP
c++openglrotation
norman
norman

Reputation: 5576

How can I change an object's rate of rotation in OpenGL?

I'm working with a simple rotating polygon that should speed up when the user clicks and drags upwards and show down when the user clicks and drags downward. Unfortunately, I have searched EVERYWHERE and cannot seem to find any specific GL function or variable that will easily let me manipulate the speed (I've searched for "frame rate," too...)

Is there an easy call/series of calls to do something like this, or will I actually need to do things with timers at different segments of the code?

Upvotes: 0

Views: 1851

Answers (1)

Nicol Bolas
Nicol Bolas

Reputation: 474036

OpenGL draws stuff exactly where you tell it to draw the stuff. It has no notion of what was rendered the previous frame or what will be rendered the next frame. OpenGL has no concept of time, and without time, you cannot have speed.

Speed is something you have to manage. Generally, this is done by taking your intended speed, multiplying it by the time interval since you last rendered, and adding that into the current rotation (or position). Then render at that new orientation/position. This is all up to you however.

Upvotes: 7

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