Multi-pass blur shader example

build.settings

settings =
{
	android =
	{
	--        versionCode = "3"
	},

	androidPermissions =
	{
		"android.permission.INTERNET"
	},

	orientation =
	{
			default = "landscape"
	},

	excludeFiles =
    {
        -- 
        all = {},

        -- Exclude all Android icon files and .ogg files
		-- TODO: Filter out auxiliary Android databases; needs some naming convention (right now, seems to be either root-level or ending in "_assets"?)
        iphone = { "Icon-*dpi.png", "*.ogg" },

        -- Exclude iOS "retina" image files and .m4a files
		-- TODO: Filter out images, etc. that would get incorporated into the database (mentioned above for iphone); again, needs naming convention
        android = { "Icon.png", "*@2x.png", "*.m4a" } 
    }
}

Image.jpg

main.lua

--- Multi-pass shader-based blur example.

--
-- Permission is hereby granted, free of charge, to any person obtaining
-- a copy of this software and associated documentation files (the
-- "Software"), to deal in the Software without restriction, including
-- without limitation the rights to use, copy, modify, merge, publish,
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-- permit persons to whom the Software is furnished to do so, subject to
-- the following conditions:
--
-- The above copyright notice and this permission notice shall be
-- included in all copies or substantial portions of the Software.
--
-- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
-- EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-- MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
-- IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
-- CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
-- TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
-- SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
--
-- [ MIT license: http://www.opensource.org/licenses/mit-license.php ]
--

do
	-- Kernel --
	local kernel = { category = "filter", name = "gradient" }

	kernel.isTimeDependent = true

	kernel.fragment = [[
		P_COLOR vec4 FragmentKernel (P_UV vec2 uv)
		{
			P_POSITION float pos = sin(CoronaTotalTime * 1.3);
			P_POSITION float where = 2. * uv.x - 1.;
			P_POSITION float diff = abs(where - pos);

			return vec4(pow(log(1. + diff), 1.7), 0., 0., 1.);
		}
	]]

	graphics.defineEffect(kernel)
end

do
	-- Kernel --
	local kernel = { category = "filter", name = "stretch" }

	kernel.isTimeDependent = true

	kernel.fragment = [[
		P_COLOR vec4 FragmentKernel (P_UV vec2 uv)
		{
			P_UV float stretch = 65. * CoronaTexelSize.z * texture2D(CoronaSampler0, uv).r;
		
			P_COLOR vec4 middle = texture2D(CoronaSampler1, uv);
			P_COLOR vec4 left = texture2D(CoronaSampler1, uv - vec2(stretch, 0.));
			P_COLOR vec4 right = texture2D(CoronaSampler1, uv + vec2(stretch, 0.));

			return middle * .75 + left * .125 + right * .125;
		}
	]]

	graphics.defineEffect(kernel)
end

do
	-- Kernel --
	local kernel = { category = "filter", name = "stretch_gradient" }

	kernel.graph = {
	   nodes = {
		  gradient = { effect = "filter.custom.gradient", input1 = "paint1" },
		  stretch = { effect = "filter.custom.stretch", input1 = "gradient" },
	   }, output = "stretch",
	}

	graphics.defineEffect(kernel)
end

local rect = display.newRect(display.contentCenterX, display.contentCenterY, 300, 300)

-- rect.fill.effect = "filter.custom.gradient"

---[[
rect.fill = {
    type = "composite",
    paint1 = { 1 },
    paint2 = { type = "image", filename = "Image.jpg" }
}

rect.fill.effect = "filter.custom.stretch_gradient"
--]]