Better Clear for RennderTarget

antix · October 2015

I would like to suggest/request that there should be some more functionality in RenderTarget so you can opt to clear a rectangular area of the RenderTarget. Maybe a new method called RenderTarget:clearRect(x1, y1, x2, y2, color, alpha)

Only being able to clear the entire thing imposes nasty limitations on RenderTargets.

In theory it should be easy to implement since you can already clear the entire RenderTarget.

hgy29 · October 2015

Well in fact, OpenGL only propose a global clear function (glClear), so we want to clear a single part, we have to find some other way. I am pretty sure there should be some blending op which would allow that, perhaps not accessible through lua yet.
Can you add a feature request (issue) on github about that ?

keszegh · October 2015

that would be good, maybe here they explain the opengl way.. http://forums.tigsource.com/index.php?topic=15619.0

antix · October 2015

@hgy29 - Cool, submitted. Maybe a new blendMode Sprite.REPLACE that overwrites the destination with the source exactly?

SinisterSoft · October 2015

This would be useful, or/and optional clear parameters that do the same as clear but clipped to a specific area.

antix · March 2016

So will something like this ever be added? Can it even be added?

SinisterSoft · March 2016

It was enhanced to have the optional x,y,w,h:

http://docs.giderosmobile.com/reference/gideros/RenderTarget/clear#RenderTarget:clear

antix · March 2016

@SinisterSoft, awesome! When was that done? I never saw any mention in release notes

antix · March 2016

So how does this actually work?

In the following code when I load my backdrop image I want the 128x128 sized area at location 0,128 of the RenderTarget to be cleared. Instead the whole thing is still being cleared.

local texture_atlas
local backdrop
local player
 
local texture_regions = {
  {  0, 128, 128, 128}, -- BACKDROP
  {  0,   0,  64,  64}, -- PLAYER
}
 
local function getRegion(region)
  local r = texture_regions[region]
  return TextureRegion.new(texture_atlas, r[1], r[2], r[3], r[4])
end
 
local function loadAtlas()
  texture_atlas = RenderTarget.new(256, 256)
  texture_atlas:draw(Bitmap.new(Texture.new("atlas.png")))
end
 
local function loadBackdrop(number)
  texture_atlas:clear(0x000044, 1, 0, 128, 128, 128) -- CLEAR ONLY THE SPECIFIC REGION OF THE ATLAS
  local bitmap = Bitmap.new(Texture.new("backdrop"..number..".png"))
  bitmap:setPosition(0, 128)
  texture_atlas:draw(bitmap)
end
 
loadAtlas()
loadBackdrop(1)
 
player = Bitmap.new(getRegion(2))
backdrop = Bitmap.new(getRegion(1))
 
stage:addChild(backdrop)
stage:addChild(player)

What am I doing wrong here? I'm using Gideros 2015.10

antix · March 2016

Cancel that.. I just downloaded 2015.12 and it's working now :-B

SinisterSoft · March 2016

Must have been added then.

antix · March 2016

Must have been. It is really a fantastic feature to have!

Howdy, Stranger!

Categories

In this Discussion

Top Posters

Better Clear for RennderTarget

Comments

Howdy, Stranger!

Quick Links

Categories

In this Discussion

Top Posters

Better Clear for RennderTarget

Comments