--[[
AlexaV3LogC ViewShader Fuse by Stefan Ihringer (stefan@bildfehler.de)
Converts Alexa's LogC into linear gamma space and back.
Also added option to convert directly to sRGB for viewing LogC images on the fly.
Based on GainGammaVS.fuse.
]]--

shader = 
[[
struct AlexaV3LogC : ViewShader
{
	ViewShader source;					// need this line
	float mode;							// 0 = log-to-lin, 1 = lin-to-log

	void ShadePixel(inout FuPixel f)
	{
		source.ShadePixel(f);			// get source pixel
		
		if (mode == 2) {
			// lin to log
			f.Color.rgb = f.Color.rgb > 0.01062324f ? log10((f.Color.rgb + 0.00937677f) / 0.18f) * 0.2471894f + 0.385537f : (((f.Color.rgb + 0.00937677f) / 0.18f + 0.04378604f) * 0.9661776f);
		} else {
			// log to lin
			f.Color.rgb = (f.Color.rgb > 0.1496582f ? pow(float3(10,10,10), (f.Color.rgb - 0.385537f) / 0.2471896f) : f.Color.rgb / 0.9661776f - 0.04378604f) * 0.18f - 0.00937677f;
			if (mode == 1) {
				// lin to sRGB
				f.Color.rgb = f.Color.rgb > 0.0031308 ? 1.055f * pow(f.Color.rgb, float3(1,1,1) / 2.4f) - 0.055f : 12.92f * f.Color.rgb;
			}
		}
	}
};
]]

-- regnode
FuRegisterClass("AlexaV3LogCVSFuse", CT_ViewLUTPlugin, {		-- ID must be unique
	REGS_Name = "AlexaV3LogC Fuse",
	REG_Fuse_NoEdit   = true,
	REG_Fuse_NoReload = true,
	})
	
-- Called on creation. Add any controls here.
function Create()
	InMode = self:AddInput("Conversion Mode", "ConversionMode", {
		LINKID_DataType      = "Number",
		INPID_InputControl   = "MultiButtonControl",
		INPID_Default        = 0,
		{MBTNC_AddButton     = "LogC to Linear" },
		{MBTNC_AddButton     = "LogC to sRGB" },
		{MBTNC_AddButton     = "Linear to LogC" },
		MBTNC_StretchToFit   = true,
		MBTNC_ShowName       = true,
		})
end

-- This is called when the shader is created
-- img may be nil
function SetupShader(req, img)
	local vs = ViewShader("AlexaV3LogC", shader)	-- pass struct name and shader string
	modeparam = vs:AddParam("mode");				-- add any external parameters 
	return vs
end

-- This is called every display refresh
-- img may be nil
function SetupParams(req, vs, img)	
	local mode = InMode:GetValue(req).Value			-- retrieve control values
	vs:SetParam(modeparam, mode)					-- and setup the shader's parameter values
	return true
end