-- Loads a sun + sky environment from the Sun and Reflection sections of an IBL file
-- 
-- @description Loads a sun + sky environment from an IBL file
-- @author      Roeland Schoukens
-- @shortcut    
-- @script-id   load-sIBL
-- @version     0.2
--

-- As an alternative to checking the version number, you can test if
-- the features you're using are there:
if not octane.NT_FILE then error("Octane version too old, this script requires version 2.11 or later.") end

local inputs
local environmentNode
local textureNode
local iblEnvironmentPower = 0
local iblSunDirection
local defaultName = octane.apiinfo.getGraphInfo(octane.GT_SCRIPTED).defaultName


local function setName(graph, name)
    -- if the graph still has the default name, set it to the name specified in the header
    if graph.name == defaultName or graph.name == "" then
        graph.name = name
    end
    
    defaultName = name
end


-- loads an IBL file and update our nodes with information from this file.
function updateEnvironment(graph, file)
    -- magic number in Octane.
    local BORDER_MODE_CLAMP = 3

    -- magic numbers used in sIBL files for the REFmap values
    local LON_LAT, CYLINDRICAL, ANGULAR, SCREEN = 1, 2, 3, 4
    -- show error
    function showError(s)
        octane.gui.showDialog{
            type = octane.gui.dialogType.BUTTON_DIALOG,
            text = s,
            title = "load sIBL"
        }
    end


    -- parse an INI value
    function parseval(v)

        -- nil
        if v == nil then return nil end
        v = v:match("^%s*(.-)%s*$")
        if v == "" then return nil end

        -- quoted string
        local str = v:match('"(.*)"')
        if str ~= nil then return str end
        
        -- color
        local r, g, b = v:match("([%d.]+),([%d.]+),([%d.]+)")
        if b ~= nil then
            return {tonumber(r), tonumber(g), tonumber(b)}
        end
        
        -- float
        local fl = tonumber(v)
        if fl ~= nil then return fl end
        
        -- return token as string
        return v
    end

    -- data we're loading
    
    -- section headers we read from sIBL files. For now we only support sun+environment,
    -- note that some files contain other lights.
    local ibl = {
        Header     = {},
        Reflection = {},
        Sun        = {},
    }

    local section = nil

    -- parse the sIBL file (INI syntax)

    for line in io.lines(file) do
        local sectionTitle = line:match("%[(.+)%]")
        if sectionTitle ~= nil then
            section = ibl[sectionTitle]
        elseif section ~= nil then
            local k, v = line:match("%s*(%a+)%s+=%s+(.+)")
            if k ~= nil then section[k] = parseval(v) end
        end
    end

    -- we want a REF and SUN section

    if not ibl.Reflection.REFfile or not ibl.Sun.SUNu then
        showError("We can load only sIBL files with an environment + sun")
        return
    end

    -- helper function to put a node of some type in a pin, and optionally set a value
    function PN(node, pin, type, attrId, value)
        local n = octane.node.create {
            pinOwnerNode = node,
            pinOwnerId = pin,
            type = type
        }
        if attrId ~= nil and value ~= nil then
            n:setAttribute(attrId, value)
        end
        return n
    end

    -- We are not doing conversions between environment mapping systems...
    if ibl.Reflection.REFmap == LON_LAT then
        -- some values can be applied directly
        local texFile = octane.file.join(file, "..", ibl.Reflection.REFfile)

        textureNode.name = octane.file.getFileName(texFile)
        textureNode:setAttribute(octane.A_FILENAME, texFile)
        
        textureNode:setPinValue(octane.P_GAMMA, ibl.Reflection.REFgamma)
        iblEnvironmentPower = ibl.Reflection.REFmulti
        PN(textureNode, octane.P_TRANSFORM, octane.NT_TRANSFORM_VALUE, octane.A_TRANSLATION, {ibl.Reflection.REFu, ibl.Reflection.REFv, 0})
        
        -- set texture mapping, taking north offset into account
        local projection = PN(textureNode, octane.P_PROJECTION, octane.NT_PROJ_SPHERICAL)

        -- calculate the sun direction
        ibl.Sun.SUNu = ibl.Sun.SUNu + ibl.Reflection.REFu
        ibl.Sun.SUNv = ibl.Sun.SUNv + ibl.Reflection.REFv
        
        local sinth = math.sin(ibl.Sun.SUNv * math.pi)
        
        local x = - math.sin(ibl.Sun.SUNu * 2 * math.pi) * sinth
        local y = math.cos(ibl.Sun.SUNv * math.pi)
        local z = math.cos(ibl.Sun.SUNu * 2 * math.pi) * sinth

        iblSunDirection = {x, y, z}
        PN(environmentNode, octane.P_SUN_DIR, octane.NT_FLOAT)
        
    else
        showError("We can only render environments with lon-lat mapping")
    end

    setName(graph, ibl.Header.Name)

    -- we are ignoring ibl.Sun.SUNmulti and ibl.Sun.SUNcolor, since Octane varies both the
    -- sun brightness and sun color depending on where it is in the sky.
end


local T = {}

function T.onInit(self, graph)

    inputs = graph:setInputLinkers{
        { type = octane.PT_STRING, label="file", defaultNodeType=octane.NT_FILE, filePattern="*.ibl" },
        { type = octane.PT_FLOAT, label="sun power",         fromNodeType=octane.NT_ENV_DAYLIGHT, fromPinId=octane.P_POWER },
        { type = octane.PT_FLOAT, label="environment power", fromNodeType=octane.NT_ENV_DAYLIGHT, fromPinId=octane.P_POWER },
        { type = octane.PT_FLOAT, label="sun size",          fromNodeType=octane.NT_ENV_DAYLIGHT, fromPinId=octane.P_SUN_SIZE },
        { type = octane.PT_TRANSFORM, label="transform",     fromNodeType=octane.NT_PROJ_SPHERICAL, fromPinId=octane.P_TRANSFORM },
    }
    
    local outputs = graph:setOutputLinkers{
        { type = octane.PT_ENVIRONMENT, label="environment" }
    }
    
    environmentNode = octane.node.create{ type=octane.NT_ENV_DAYLIGHT, name="environment", graphOwner=graph }
    textureNode = octane.node.create{ type=octane.NT_TEX_IMAGE, graphOwner=graph }
    environmentNode:connectTo(octane.P_TEXTURE, textureNode)
    outputs[1]:connectTo(octane.P_INPUT, environmentNode)
    environmentNode:connectTo(octane.P_SUN_SIZE, inputs[4])

    -- set icon, and release base64 blob
    self:setIcon(octane.image.fromBase64(self.iconData, octane.image.channels.COLOUR))
    self.iconData = nil
    setName(graph, "sIBL environment")
end

function T.onEvaluate(self, graph)
    if self:inputWasChanged(inputs[1]) then
        local file = self:getInputValue(inputs[1])
        if file ~= "" then
            updateEnvironment(graph, file)
        end
    end
    
    if iblSunDirection then
        local xform = self:getInputValue(inputs[5])
        -- adapt the sun direction to the transform. This doesn't work with translations,
        -- solving this for translations is hard.
        local dir = octane.matrix.mulP(xform, iblSunDirection)
        dir = octane.vec.normalized(dir)
        environmentNode:setPinValue(octane.P_POWER, self:getInputValue(inputs[2]))
        environmentNode:setPinValue(octane.P_SUN_DIR, dir)
        textureNode:getInputNode(octane.P_PROJECTION):setPinValue(octane.P_TRANSFORM, xform)
        textureNode:setPinValue(octane.P_POWER, self:getInputValue(inputs[3]) * iblEnvironmentPower / self:getInputValue(inputs[2]))
    end
    
    return true
end

-- base64 encoded PNG file. If we put it in our table like this we can put this chunk at
-- the bottom of our script.
T.iconData = 
  [[iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAABHNCSVQICAgIfAhkiAAAAkNJREFUOI2Nkb9LW1Ecxc/NDfnxHjg4FC
  uCdHhLBlsaxf4Jbq5m6h4kBbf+AaXgYsXB0VkQBMHNCCYIDnmWPkM1iNGhESSJj/pK3qXv3Xs6SNKipu2ZvsP5HM73+xV4WtbU1NT72d
  nZt+l0OtNqtWrb29sfAVSH+H8rmUy+293dJUne3d2xr1arxUKh8PWvcCKRKPm+z+PjY3NyckKllCHJOI6NMYYkubi4+GMYb+3s7NDzPB
  MEAbXWRmvNPhjHsdFakyRzudzqIzqXy30gSc/zBjBJ9no9djodhmFIrTW11mZjY4ODlftDPp8vttttTExMUAghtNY4ODhAvV6HUgqFQg
  FjY2OUUoqZmRkAcACcDwKklKkoimDbthBCYG9vD77vo1gsQkqJRqMBKaUAANu2AcAGgEQ/4Pr6ujw+Po5UKkUA6HQ6mJ+fRyJxb1FKgS
  SFELi8vASA84dneHl6ekqtNeM4NiRZqVQYhiFJ0nXdwUuXlpYewQCAubm5CkkaYwYH29/fJ0k2Gg2jlKLneQTwetgrsbCw0IzjmP0gkj
  w8PCRJlstllkol/0+/fBhQr9dX19bWwmQy+SaKonQQBAiCgFtbW5icnBRKqUw+n7+qVqtfAEAMrXKvLIBny8vLV47j4ObmBkIInp2d/V
  xZWck82eCBYgDfp6enX1iW9arb7YKkyGazScdxvtVqtc+JfwQAALrdbrHZbEJKCcuykMlksL6+7v5PAwCA67rR6Ohob2Rk5PnFxUV7c3
  Pz6Pb29hMA/ALZznx4mDAKFgAAAABJRU5ErkJggg==]]


return T