2016-06 RenderTarget bug on older devices

totebo

On older devices RenderTarget fails to copy any pixels if the area is very narrow, in my case for an energy bar. This code shows the issue.

local shape = Shape.new() shape:setFillStyle(Shape.SOLID, 0xff0000, 1) shape:beginPath() shape:moveTo(0,0) shape:lineTo(100, 0) shape:lineTo(100, 100) shape:lineTo(0, 100) shape:lineTo(0, 0) shape:endPath() stage:addChild(shape)   local width = 100 local height = 5 -- Using a value of 10 works on all devices local rt = RenderTarget.new( width, height ) local bitmap = Bitmap.new( rt ) rt:draw( shape ) bitmap:setX( 125 ) stage:addChild( bitmap )

On these devices no pixels are copied:

- iPad 2
- iPod Touch 5th generation
- iPhone 5

On these it works fine (all pixels are copied):

- Local Gideros Player
- Nexus 6
- iPad Mini Retina


A workaround could be to keep adding pixels to the height until something shows up, but this makes the energy bar (in my case) too tall. Is this a known issue?

I've also added an issue on Github here: https://github.com/gideros/gideros/issues/241

hgy29

Looks like a device dependant FBO restriction to me, but there are workaround. First I can think of is enlarge your rendertarget but clip the Bitmap that uses it. Second thought is do you need a rendertarget at all ?

totebo

Okay, clipping the bitmap can work. I'll give it a go.

In this case I do need RenderTarget, or... actually, maybe I could just clip the bitmap? Will come back after some tests.

totebo

Doh! setClip() to the rescue. The code is so much cleaner. Thanks for the nudge @hgy29!

SinisterSoft

Does rendertarget to the power of two not work? Then clip it? Or is that what you have done?

totebo

Yeah, I use setClip now and that works. I had to add 1px to around the clip for some reason, because the exact coordinates cropped it a little. But it works, whereas RenderTarget didn't.

SinisterSoft

I think rendertarget works as in 0 to width-1 and 0 to height-1 rather than 1 to width and 1 to height when plotting coords.