Sprite:setBlendMode

From GiderosMobile

Available since: Gideros 2011.6
Class: Sprite

Description

Sets the blend mode of the sprite. 

Sprite:setBlendMode(blendMode or src,dst)

This method can be called with 1 or 2 parameters.

If one parameter is passed it must be one of the following blending modes:

  • Sprite.ALPHA = "alpha"
  • Sprite.NO_ALPHA = "noAlpha"
  • Sprite.ADD = "add"
  • Sprite.MULTIPLY = "multiply"
  • Sprite.SCREEN = "screen"

If a Sprite object doesn't set any blending mode, it takes the blending mode from its parent sprite.

Note: the following two lines are completely the same: 

sprite:setBlendMode("add")
sprite:setBlendMode(Sprite.ADD)

It's a matter of taste which one to choose.


If two parameters are passed to this method, then a source and destination blend can be set (in that order) and each takes the values:

  • Sprite.ZERO = "zero"
  • Sprite.ONE = "one"
  • Sprite.SRC_COLOR = "srcColor"
  • Sprite.ONE_MINUS_SRC_COLOR = "oneMinusSrcColor"
  • Sprite.DST_COLOR = "dstColor"
  • Sprite.ONE_MINUS_DST_COLOR = "oneMinusDstColor"
  • Sprite.SRC_ALPHA = "srcAlpha"
  • Sprite.ONE_MINUS_SRC_ALPHA = "oneMinusSrcAlpha"
  • Sprite.DST_ALPHA = "dstAlpha"
  • Sprite.ONE_MINUS_DST_ALPHA = "oneMinusDstAlpha"
  • Sprite.SRC_ALPHA_SATURATE = "srcAlphaSaturate"

Parameters

blendMode or src: (String) if one parameter is used, this is the blend mode. If two parameters are used this is the source blend specification
dst: (String) destination blend mode optional

Examples

All blend modes 

for x = 1, 11 do
	for y = 1, 11 do
		local top = Pixel.new(topTex, s, s)
		local btm = Pixel.new(btmTex, s, s)
		stage:addChild(btm)
		btm:addChild(top)
		btm:setBlendMode(x, y)
		btm:setPosition(lh + s * (x-1), lh + s * (y-1))
	end
end

Spot light 

note: you have to provide your own asset

--[[
    Script:  spotlight
	Description: Show how to create an animated spot light of the Gideros logo
	Author:  Michael Hartlef
	Contact: mike@fantomgl.com
--]]

-- Load the mask images (can be a gradient or a plain image)
--local mask = Bitmap.new(Texture.new("images/maskCircle2.png")) -- semi-transparent
local mask = Bitmap.new(Texture.new("images/carmo.png")) -- plain image
-- Set its anchor point in the center
mask:setAnchorPoint(0.5, 0.5)
-- Scale it up by a factor of 3
mask:setScale(3)
-- change alpha
mask:setAlpha(2)
-- Position the mask in the middle of the simulator
mask:setPosition(application:getLogicalHeight()/2,application:getLogicalWidth()/2)
-- Set its speed and direction values
mask.speedX = 2
mask.speedY = 1
mask.dirX=1
mask.dirY=1
--Add the mask to the stage
stage:addChild(mask)

--Now load the logo image
local logo = Bitmap.new(Texture.new("images/carmo.png"))
-- Set its anchor point to the center
logo:setAnchorPoint(0.5, 0.5)
-- Scale it down to a half
logo:setScale(10)
-- Position the logo in the middle of the simulator
logo:setPosition(application:getLogicalHeight()/2,application:getLogicalWidth()/2)
--Now set the blend mode
logo:setBlendMode(Sprite.MULTIPLY)
-- Add the logo to the stage
stage:addChild(logo)

-- Set the background color of the stage to black (you can experiment)
stage:setBackgroundColor(0.07, 0.07, 0.07) -- r, g, b

-- Define the onEnterFrame event function. This deals with the positioning of the mask
function onEnterFrame(event)
	-- Get the position of the maks
	local x, y = mask:getPosition()
	-- Calculate the new position
	x += (mask.speedX * mask.dirX)
	y += (mask.speedY * mask.dirY)
	-- Check if the mask reaches the edges of the canvas and then mirror its movement.
	if x < 0 then mask.dirX = 1 end
	if x > application:getLogicalHeight() then mask.dirX = -1 end
	if y < 0 then mask.dirY = 1 end
	if y > application:getLogicalWidth() then mask.dirY = -1 end
	-- Set the new position of the mask
	mask:setPosition(x,y)
end

-- Register an enterFrame event handler function
stage:addEventListener(Event.ENTER_FRAME, onEnterFrame)





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