jonathanharvey@dsl.pipex.com

I wish to control an OpenGL circle object with two pieces of data.

The first value (-5 & 5) should determine direction and speed of the moving object. So, -5 is backwards, 5 is forwards. -5 is extremely fast backwards, -3 is not so quick, 2 is fairly slow forwards and 5 is extremely quick forwards. A bit like the forwards/backwards inputs from a radio control transmitter.

The second value controls the angle of travel of the circle 0 being vertically upwards, 180 downwards and so on.

Basically, the first value (speed/direction) is relative to the object only. The second value (rotation) is relative to the screen

Can anybody help me with this please as I am unsure of how to translate the two values.

1. a value between -5 & 5
2. a value between 0 and 360.

The first value (-5 & 5) should determine direction and speed of the moving object.  So, -5 is backwards, 5 is forwards.  -5 is extremely fast backwards, -3 is not so quick, 2 is fairly slow forwards and 5 is extremely quick forwards.  A bit like the forwards/backwards inputs from a radio control transmitter.

Basically, the first value (speed/direction) is relative to the object only.  The second value (rotation) is relative to the screen

Speed and direction of an object. Help please.