Rotating the level?

Hey All,

I am trying to come up with a way to rotate a game level. The level is made of active object tiles, so I need to find some way to rotate everything around a common pivot point. Is there any extension or straight forward coding method that can do this?

Thanks in advance,

Mobichan

Oh... I thought about this a long time ago but I gave it up...

If you really have only actives it should be possible quickly with a formula.
I have had a lot of pasted graphics in an Overlay object to save resources but
if I wanted to rotate the level it would be like loading a new map and took a long time.

there was supposed to be a new version of the Viewport object that allowed you to do this. not sure what happened to it though.

There was a whole thread discussion over this and it turned out quite nice. Try doing a search. ;)

Quote:

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Originally Posted by lembi2001

there was supposed to be a new version of the Viewport object that allowed you to do this. not sure what happened to it though.

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rotation is implemented in the open-source version and works if you compile it

it depends on whether viewport technically counts as "rotating" the level

The viewport method will be too slow for runtime.
The only effective method I found for this, and I'm doing the exact same effect heavily on my current project, is to use a pixel shader in HWA. I'm sure you can find a more efficient one using matrix transformations and I've been meaning to make one, but you can feel free to use this shader I wrote if you load HWA up:

http://sites.google.com/site/claniraq/stuff/PT_Rotate.fx?attredirects=0&d=1
http://sites.google.com/site/claniraq/stuff/PT_Rotate.xml?attredirects=0&d=1

Quote:

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Originally Posted by Pixelthief

The viewport method will be too slow for runtime.

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i dunno i got full 60fps out of a 384 x 384 window in software mode when i tried

though there was barely any other logic running at the time (apart from player movement and a couple other objects) so things could change in that respect

Is there some method to get this to work for the Flash runtime? I haven't looked into the Viewport extension, so I'll test it out. The thing is, I am probably going to "fake" the screen rotating. The game involves falling down a tunnel. When the player hits a particular object, the tunnel needs to appear to rotate 90 degrees, so that a side tunnel opening that was on the wall, will rotate to be below the player (at the bottom of the screen). This is purely a transition, so the player will not have control (and the game will basically be frozen during the rotation) when the rotation happens. I could maybe get away with making a screen capture and pasting it at runtime (is that even possible?) but I need some guidance on how to do that at runtime.

Thanks for the ideas so far,

Mobichan

But this is not really a solution ...

And how about isometric games?

Or, you could just teleport to an identical area with the pipe as an active object, rotate that, then teleport to the other part of the level. :\

Pixelthief and didn't you have an example at TDC?

I saw the thread in HWA about a rotation shader, but I am not using HWA and I actually need this to work in Flash. Can anyone direct me to any tutorials that might explain the concepts behind rotating many objects around a common point? I'd really appreciate it. ^_^

Mobichan

I did a basic version of this for Mind Twister. I used trigonometry applied to all active objects. I did it with a fast loop. I also used no background objects (which can't be rotated)

get object distance from point of rotation (distance formula) which is our hypotenuse
get current angle from point of rotation (atan2 formula) for each object
set angle (eg. current angle + 5 degrees) for each object

so you have angle and hypotenuse

you need x and y

cos (angle) = adj/hyp
adj = cos (angle) * hyp
or x = cos (angle) * hyp

sin (angle) = opp/hyp
opp = sin (angle) * hypotenuse
or y = sin (angle) * hypotenuse

set object position x to point of rotationx + x
set object position y to point of rotationy + y
set object angle to angle

if you don't have solid knowledge of trig, then you may struggle with it

Thanks. I'll give this a try. :) As for my question about faking the rotation by screen capping the level and then pasting it as an active, can this be done? I know the Active Picture Object can paste backdrops, but is there a way to change the appearance of an active object at runtime from a screen cap?

Animation --> Load Frame

I have never used this, though. ;)

If your game is made from tiles and you are rotating at 90 degree angles, its easy enough. Read up on image rotation and apply the formula to your map array and viola. I did this with one of the test engines I made a while ago and will eventually implement it into my extension im making.