--[[
Letterbox Overlay ViewShader Fuse by Stefan Ihringer (stefan@bildfehler.de)

This shader allows you to create a letterbox overlay as part of your LUT chain
(usually the final one). It has a few presets for common film and HD formats but
it also allows you to define a custom letterbox, which is either specified as an
aspect ratio or by specifying the height of the top and bottom border in actual
pixels. The latter allows you to perfectly match a frame leader that is off-
center and requires you to specify the reference height of a full frame.

The major difference from Fusion's own guides overlay is the fact that this
fuse works for any frame size. This means, it will always show a letterbox of
the desired aspect ratio, whether you're viewing an anamorphic PAL reference
edit or the actual 2K plate.

----------------------------------------------------------------------
Copyright (c) 2012, Stefan Ihringer
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met: 

1. Redistributions of source code must retain the above copyright notice, this
   list of conditions and the following disclaimer. 
2. Redistributions in binary form must reproduce the above copyright notice,
   this list of conditions and the following disclaimer in the documentation
   and/or other materials provided with the distribution. 

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
----------------------------------------------------------------------
]]--

shader = 
[[
struct LetterboxOverlay : ViewShader
{
	ViewShader source;			// need this line
	float top, bottom;			// top and bottom border of black area (normalized coordinates, 0.0 is bottom)
	float opacity;

	void ShadePixel(inout FuPixel f)
	{
		source.ShadePixel(f);			// get source pixel
		if (f.TexCoord1.y < bottom || f.TexCoord1.y > top) {
			f.Color *= opacity;
		}
	}
};
]]

-- regnode
FuRegisterClass("LetterboxOverlayVSFuse", CT_ViewLUTPlugin, {		-- ID must be unique
	REGS_Name = "Letterbox Overlay",
--	REG_Fuse_NoEdit   = true,
--	REG_Fuse_NoReload = true,
})
	
-- Called on creation. Add any controls here.
function Create()
	InPreset = self:AddInput("Preset", "Preset", {
		LINKID_DataType      = "Number",
		INPID_InputControl   = "ComboControl",
		INP_Default          = 1,
		INP_Integer          = true,
		{CCS_AddString       = "custom" },
		{CCS_AddString       = "1.78 (HD 16:9)" },
		{CCS_AddString       = "1.85 (35mm theatrical)" },
		{CCS_AddString       = "2.39 (square pixels)" },		-- this will give you a 2.39:1 letterbox on square pixels
		{CCS_AddString       = "2.39 (2:1 anamorphic)" },		-- this will give you a 2.39:1 letterbox on anamorphic pixels
		INP_DoNotifyChanged  = true,
		})
	InMeasurement = self:AddInput("Measurement", "Measurement", {
		LINKID_DataType      = "Number",
		INPID_InputControl   = "MultiButtonControl",
		INP_Integer          = true,
		{MBTNC_AddButton     = "Aspect",  MBTNCD_ButtonWidth = 0.5, },
		{MBTNC_AddButton     = "Pixels",  MBTNCD_ButtonWidth = 0.5, },
		INP_DoNotifyChanged  = true,
		IC_Visible           = false,
		})
	InAspect = self:AddInput("Aspect Ratio", "Aspect", {
		LINKID_DataType    = "Number",
		INPID_InputControl = "SliderControl",
		INP_MinAllowed     = 1.0,
		INP_MaxScale       = 4.0,
		INP_Default        = 1.78,
		IC_Steps           = 0.1,
		IC_Visible         = false,
		})
	InTopBorder = self:AddInput("Top Border", "TopBorder", {
		LINKID_DataType    = "Number",
		INPID_InputControl = "SliderControl",
		INP_MinAllowed     = 0.0,
		INP_MaxScale       = 400,
		INP_Integer        = 1,
		INP_Default        = 48,
		IC_Visible         = false,
		})
	InBottomBorder = self:AddInput("Bottom Border", "BottomBorder", {
		LINKID_DataType    = "Number",
		INPID_InputControl = "SliderControl",
		INP_MinAllowed     = 0.0,
		INP_MaxScale       = 400,
		INP_Integer        = 1,
		INP_Default        = 280,
		IC_Visible         = false,
		})
	InRefWidth = self:AddInput("Reference Width", "ReferenceWidth", {
		LINKID_DataType    = "Number",
		INPID_InputControl = "SliderControl",
		INP_MinAllowed     = 0.0,
		INP_MaxScale       = 2048,
		INP_Integer        = 1,
		INP_Default        = 2048,
		IC_Visible         = false,
		})
	InRefHeight = self:AddInput("Reference Height", "ReferenceHeight", {
		LINKID_DataType    = "Number",
		INPID_InputControl = "SliderControl",
		INP_MinAllowed     = 0.0,
		INP_MaxScale       = 2048,
		INP_Integer        = 1,
		INP_Default        = 1168,
		IC_Visible         = false,
		})
	InOpacity = self:AddInput("Opacity", "Opacity", {
		LINKID_DataType    = "Number",
		INPID_InputControl = "SliderControl",
		INP_MinAllowed     = 0.0,
		INP_MaxAllowed     = 1.0,
		INP_Default        = 1.0,
		IC_Steps           = 0.1,
		})
end

-- This is called when the shader is created
-- img may be nil
function SetupShader(req, img)
	local vs = ViewShader("LetterboxOverlay", shader)	-- pass struct name and shader string
	vs:AddParam("top")
	vs:AddParam("bottom")
	vs:AddParam("opacity")
	return vs
end

-- This is called every display refresh
-- img may be nil
function SetupParams(req, vs, img)	
	local preset = InPreset:GetValue(req).Value			-- retrieve control values
	local use_aspect = InMeasurement:GetValue(req).Value < 1
	local custom_aspect = math.max(1, InAspect:GetValue(req).Value)
	local topborder = math.floor(InTopBorder:GetValue(req).Value + 0.5)
	local bottomborder = math.floor(InBottomBorder:GetValue(req).Value + 0.5)
	local ref_width = math.floor(InRefWidth:GetValue(req).Value + 0.5)
	local ref_height = math.floor(InRefHeight:GetValue(req).Value + 0.5)

	local opacity = 1 - math.max(0, math.min(1, InOpacity:GetValue(req).Value))

	-- get frame size and calculate top and bottom border
	local ref_aspect = ref_width / ref_height
	local imageaspect = img.Width / img.Height * (img.XScale / img.YScale)
	local top, bottom
	local h = 1

	if preset == 0 then
		-- custom
		if use_aspect == true then
			h = imageaspect / custom_aspect 
		else
			top = (0.5 - topborder / ref_height) * imageaspect/ref_aspect + 0.5
			bottom = (bottomborder / ref_height - 0.5) * imageaspect/ref_aspect + 0.5
		end
	elseif preset == 1 then
		-- HD 16:9
		h = imageaspect / (16/9)
	elseif preset == 2 then
		-- 1.85 : 1
		h = imageaspect / 1.85
	elseif preset == 3 then
		-- 2.39 : 1 (but on square pixels)
		h = imageaspect / 2.39
	elseif preset == 4 then
		-- 2.39 anamorphic (expects 2:1 pixel aspect ratio)
		h = (imageaspect / 2.39) * 2
	end
	
	if top == nil or bottom == nil then
		top = 0.5 + h/2
		bottom = 0.5 - h/2
	end

	-- account for the fact that TexCoord1, which is used for measuring the vertical position
	-- on a scale of [0..1] actually includes "1" as the topmost value instead of it being just
	-- outside the image borders like in Fusion's normalized coordinate system.
	-- Without this correection, the pixel measurement mode wouldn't end up on exact scanlines.
	local texcoordcorrection = img.Height / (img.Height - 1)

	vs:SetParam(1, top * texcoordcorrection)
	vs:SetParam(2, bottom * texcoordcorrection)
	vs:SetParam(3, opacity)
	return true
end

function NotifyChanged(inp, param, time)
	if inp ~= nil and param ~= nil then
		if inp == InPreset then
			if (param.Value < 1) then
				InMeasurement:SetAttrs({IC_Visible = true})
				local use_aspect = InMeasurement:GetSource(time).Value < 1
				InAspect:SetAttrs({IC_Visible = use_aspect})
				InTopBorder:SetAttrs({IC_Visible = not use_aspect})
				InBottomBorder:SetAttrs({IC_Visible = not use_aspect})
				InRefWidth:SetAttrs({IC_Visible = not use_aspect})
				InRefHeight:SetAttrs({IC_Visible = not use_aspect})
			else
				InMeasurement:SetAttrs({IC_Visible = false})
				InAspect:SetAttrs({IC_Visible = false})
				InTopBorder:SetAttrs({IC_Visible = false})
				InBottomBorder:SetAttrs({IC_Visible = false})
				InRefWidth:SetAttrs({IC_Visible = false})
				InRefHeight:SetAttrs({IC_Visible = false})
			end
		elseif inp == InMeasurement then
			local flag = InPreset:GetSource(time).Value < 1
			if param.Value < 1 then
				-- use aspect
				InAspect:SetAttrs({IC_Visible = flag})
				InTopBorder:SetAttrs({IC_Visible = false})
				InBottomBorder:SetAttrs({IC_Visible = false})
				InRefWidth:SetAttrs({IC_Visible = false})
				InRefHeight:SetAttrs({IC_Visible = false})
			else
				InAspect:SetAttrs({IC_Visible = false})
				InTopBorder:SetAttrs({IC_Visible = flag})
				InBottomBorder:SetAttrs({IC_Visible = flag})
				InRefWidth:SetAttrs({IC_Visible = flag})
				InRefHeight:SetAttrs({IC_Visible = flag})
			end
		end
	end
end