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nccb presents ...

2012/7/6

# Shooting Rocks

This is a rework of the asteroids scenario from the book, to use point-circle intersection rather than Greenfoot's built-in collision detection. See this page for an explanation:

http://sinepost.wordpress.com/2012/07/06/shooting-rocks/

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zapnine7

2012/7/6

Great! A very simple example with the Pythagorean theorem. I also have a sort of request... In eclipse there are no handy methods like "move" and "turn", so could you post the maths behind rotating an image, like Greenfoot does?
nccb

2012/7/6

The gist of rotating an image is that if you want a 30 degree clockwise rotation, then for each position in the new image, you rotate the position by 30 degrees anti-clockwise and, use the pixel from the old image that is at that position. I can add the idea to my list, but I have a bit of a pipeline going, so it will be a while before it shows up :)
zapnine7

2012/7/6

Not sure what you mean, but I'll that one sentence for many hours... Maybe I'll figure it out :) Thanks anyways! You blog is something I check everyday!
nccb

2012/7/7

It's very similar to this post: http://sinepost.wordpress.com/2012/04/10/burning-rubber/ That post looks at rotating the position of the wheel to work out where to place the tyre tracks. But instead of rotating a wheel position, you rotate the position of every pixel in the image. As I said, I will write the full post for you soon :)
MatheMagician

2012/7/12

Hey, thanks for the post on burning rubber. I was having tons of difficulty calculating the next point on a circle. Yo helped me figure it out. I will hopefully be using it to make my cube program actually work.
nccb

2012/7/24

zapnine7: I've now published the explanation of how to do image rotation, you can find it here: http://sinepost.wordpress.com/2012/07/24/image-rotation/
zapnine7

2012/7/24

Wow! Thanks so much! I really appreciate it. MatheMagician, your new picture is awesome.
MatheMagician

2012/7/24

Thanks Zapnine, and thanks nccb.
strobez2006

2014/4/18

This is awesome!