[android-developers] Re: Suggestions on best way to draw a "laser" in a 2d game

I bet you can make a pretty funky laser beam using the draw lines or
fill polygon commands in the Canvas/Paint library.

To draw basic unpulsed laser beam draw a transparent line of width 6
between a and b. Then draw on top an opaque line of width 2 between a
and b. You will get an effect where the laser beam falls off in
brighness from the centre to the edges.

To pulse it, draw a short line segment of width (say) 8 on top of the
unpulsed laser beam, and move its position between a and b every
screen refresh so the pulse moves along the line.

If you want your laser beam to be some shape other than a long thin
rectangle, you can do the same thing with a polygon fill command and
you can have the laser beam whatever shape and size you want.

On Feb 3, 7:38 pm, Mando <mando.aka.ch...@gmail.com> wrote:
> Hi, hope this is the right location to post this.
>
> I am working on a 2d android game with a light space shooter theme. I
> wanted my ship to have a turret the that tracks targets, rotates and
> fires a laser beam that is animated (maybe pulsing or with non uniform
> bulges issuing out of the turret and moving down towards the target).
>
> Key parts of the problem. laser starts at 1 coordinate and terminates
> at another in 2d space and could be of arbitrary length (might be
> scaled if I decide to add zooming).
>
> Possible brute force solutions:
> 1) using rotation/transformation to manually draw a bitmap
> representing a segment of laser all along the required distance.
> (cycling the bitmap as required for animation)
> 2) Create a very large laser beam image (longer than I would need eg:
> 10px by 500px) and draw it at correct transformation.
>
> Looking at the BitmapShader and reading some of the SDK info about
> Paths, Paints etc it feels like there should be a better way to do
> this, but no examples I've found covers it.
>
> Any idea if there is a way to use a BitmapShader to paint using a
> canvas.drawLine or canvas.drawPath call to create this effect?
>
> Thanks in advance
>
> Mando

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