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Drawing an Image FROM and Image
Posted: Thu Dec 15, 2011 12:23 am
by NeoFLoyd
I'm still learning a little Lua, though I have a decent understanding of how it works. Being the newbie I am I have become stumped.
Say I have an image called "rake.png." It is draggable by the mouse. How can I draw an image called "raketrail.png" from rake.png if rake is being dragged?
Much appreciated!
Re: Drawing an Image FROM and Image
Posted: Thu Dec 15, 2011 1:15 am
by thelinx
Looks like you need to learn about
ParticleSystems.
You can find example code in particles.love in the
demos zip archive.
Re: Drawing an Image FROM and Image
Posted: Thu Dec 15, 2011 1:48 am
by NeoFLoyd
Oh my ... that seems very complex. Would anyone be able to just post a finished code based on what I asked for? Although I'm definitely going to read up on what Linx posted, I also learn fairly well from examining the code myself.
Re: Drawing an Image FROM and Image
Posted: Thu Dec 15, 2011 2:53 am
by Taehl
Define "draw an image from an image".
Re: Drawing an Image FROM and Image
Posted: Thu Dec 15, 2011 11:02 am
by NeoFLoyd
Taehl wrote:Define "draw an image from an image".
Say I have an image called rake.png and it is draggable. I would like an image named raketrail.png to become drawn from the mouse while rake.png is dragged.
Re: Drawing an Image FROM and Image
Posted: Fri Dec 16, 2011 1:37 am
by Taehl
So far as I know, the name for that sort of thing is a "ribbon" (at least, that's what Blizzard calls them in all their games). Love, unfortunately, doesn't offer a way of drawing ribbons (yet?). I wish it did, though.
However, even if there isn't a proper way to do it, you can still fake it. A few possibilities I can think of:
- Make it pixel-art or somehow tile-based, so you don't need to draw an exact, detailed trail
- Draw a circle under each tine every frame that the rake is down, but draw it to a framebuffer instead of the screen. As long as you don't clear the framebuffer, you'll get the furrow trails you want.
- Make your own ribbon system using lots of image transforms (I'd suggest looking into the 3D dice roller demo to see the math and methods for skewing an image).
Re: Drawing an Image FROM and Image
Posted: Fri Dec 16, 2011 10:57 am
by NeoFLoyd
Darn,it stinks that there's no way to make one of these ribbons.Thanks for the useful info anyway!
Re: Drawing an Image FROM and Image
Posted: Sat Dec 17, 2011 5:05 am
by TechnoCat
Taehl wrote:Love, unfortunately, doesn't offer a way of drawing ribbons (yet?). I wish it did, though.
Create a blank framebuffer and draw to it without clearing. Every frame decrement the opacity of each pixel. I can't remember if 0.7.2 has the explicit framebuffer clearing or if 0.8.0 does.
EDIT: Indeed it requires LOVE 0.8.0. BEWARE! This example isn't dt based.
Re: Drawing an Image FROM and Image
Posted: Sat Dec 17, 2011 9:46 pm
by NeoFLoyd
TechnoCat wrote:Taehl wrote:Love, unfortunately, doesn't offer a way of drawing ribbons (yet?). I wish it did, though.
Create a blank framebuffer and draw to it without clearing. Every frame decrement the opacity of each pixel. I can't remember if 0.7.2 has the explicit framebuffer clearing or if 0.8.0 does.
EDIT: Indeed it requires LOVE 0.8.0. BEWARE! This example isn't dt based.
How would one obtain LOVE 0.8.0?
Re: Drawing an Image FROM and Image
Posted: Sat Dec 17, 2011 10:09 pm
by pk
It's not out yet, but if you're running Windows, you can get nightly builds here:
http://love2d.org/builds/
Beware that stuff which works fine on the wiki/forums for 0.7.2 might fail horribly under 0.8.0.