Rotating an object at the user specified speed in corona

Question

I am developing a globe animation ,in which the speed of the rotation changes with the length of the user's drag event.The globe when touched and moved attains positive acceleration,reaches maximum value,rotates there for sometime and starts retarding and comes back to its original position.Can anybody tell me how to do this in corona.A sample code will be really helpful

Answer 1

Well first off, Corona is a 2D SDK so I'm not sure how effective it would be to do an animated globe like this. Still, it's pretty easy to get the length of a user's drag, and then you can use that length to modify the speed of your animation.

First off, make sure to set your event listeners for "touch" and not "tap". "Touch" events respond to both the beginning and end of a user's gesture, while "tap" events simply responds to the user tapping a spot.

In the documentation for "touch" event listeners, you'll see you can check the "phase" property of the event in order to check for "began" and "ended":

http://developer.anscamobile.com/content/events-and-listeners#touch_single_touch

Simply calculate the distance from start to end when event.phase=="ended"

Answer 2

Don't do that (rendering textured sphere) with Corona SDK.

If you draw your effect with triangles using OpenGL ES, you can get around 200 FPS. If you draw your object on CPU by editing pixels in bitmap, you can get about 20 FPS. Corona has none of those options.

The only option is to draw 1x1 rectangles (display.newRect()) to draw pixels, but I really doubt you can get more than 5 FPS.