How to make a ball move round a circle?

[Stellaferox]

Hi all,

I am trying to make a ball move around a printed full circle (say a planetary orbit). How can this be achieved in the simplest way?
I am looking for the graphical implementation. The math I know.
thnx in advance
Marc

 

[klaus]

Some questions to better understand what you want to do.
- is the 'printed full circle' drawn on the form ?
- or is it an image on the background ?
- is the ball a simple circle or a bitmap ?
- do you want the ball turn around it's own center ?

A simple way would be to draw the ball on the forelayer of the form, either directly or with the ImageLibEx library.
If you need to turn a bitmap you must use the ImageLibEx library.

But the Sprite library would probably be the right library for your project.
Unfortunately I have never used it.

There exists an example for the Sprite library:
Basic4ppc - Windows Mobile programming and Pocket PC Development

Best regards.

 

[Stellaferox]

Hi Klaus,

Thanx for your answer.
The "ball" is in fact a planet. I am building a graphical representation of the solar system.
The circle of course is the orbit, which in fact is an ellipsoid, which makes it harder with the math.
I want to move the planet around the orbit. I think your suggestion is the right one. I will try this.
At first I will try to make a circle moving. When it works I usually "pimp" the program.
thnx again
Marc

 

[klaus]

Hi Stellaferox,

Here is an example of what could be done, with a circle.
Of course with an elipsoid the maths will be a little bit more tricky.

Best regards.

 

[Stellaferox]

Thnx Klaus,

Will try this one out. Have already looked at some other examples.
Marc

 

[bdiscount]

Just off the top of head you can use array pts for the elipsoid (Form1.polgon etc)and then move planet from pt to pt using the rotation in dzt's lib. just a thought