divo: Drag'n'Drop Example [VS] (...)

-- Copyright (c) 2013, Thomas Siegmund
-- All rights reserved.
--
-- Redistribution and use in source and binary forms, with or without modification, are permitted
-- provided that the following conditions are met:
--
--    * Redistributions of source code must retain the above copyright notice,
--      this list of conditions and the following disclaimer.
--
--    * 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 HOLDER 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.

local selectedObject = nil
local selectedAnim = nil
local leftMouseButtonIsPressed = 0
local firstMousePosition = nil
local mousePositionT1 = nil
local reloadSceneAction = nil

-- variables for saving the changed Parameters
local animNames = {}
local animPositions = {}
local objVisibility = {}

-- Find out if value v is in table t. If it is, then return the key, else return 0.
local function inTable(t, v)
    for key, value in pairs(t) do
        if value == v then
            return key
        end
    end
    return 0
end

-- set the current position of the given anim to pos
local function setAnimToPosition(anim, pos)
    local animPos = anim:getPoint(VAnimationCurrentPosition)
    animPos.x = pos.x
    animPos.y = pos.y
    anim:setValue(VAnimationCurrentPosition, animPos)
end

-- modify the current position of the given anim by the value of pos
local function modifyAnimToPosition(anim, pos)
    local animPos = anim:getPoint(VAnimationCurrentPosition)
    animPos.x = animPos.x + pos.x
    animPos.y = animPos.y + pos.y
    anim:setValue(VAnimationCurrentPosition, animPos)
end

-- Modify all points of obj's polygon by the value of pos.
-- You have to reload the scene to see any effect
local function modifyObjectsPolygon(obj, pos)
    local polyPoints = obj:getPoints(VObjectPolygon)
    -- only change something if there is something to change
    if table.getn(polyPoints) ~= 0 then
        for i=1,table.maxn(polyPoints) do
            polyPoints[i].x = polyPoints[i].x + pos.x
            polyPoints[i].y = polyPoints[i].y + pos.y
        end
        obj:setValue(VObjectPolygon, polyPoints)
    end
end

-- called due to an eEvtMouseMove and modifies the animation of the currently selected object
local function mouseMove(mousePosition)
    if selectedAnim ~= nil and leftMouseButtonIsPressed == 1 then
        modifyAnimToPosition(selectedAnim, {x=mousePosition.x - mousePositionT1.x, y=mousePosition.y - mousePositionT1.y})
    end
    mousePositionT1 = mousePosition
end

-- change the visibility value of the currently selected object or the object beneath the cursor
-- if the selected object is nil
local function addVisibility(i)
    local obj = nil
    if selectedObject == nil then
        obj = game:getLink(VGameCurrentObject)
    else
        obj = selectedObject
    end

    local v = obj:getInt(VObjectVisibility) + i
    local anim = getObject("ActiveAnimations["..obj:getName().."_Anim]")

    if v < 0 then
        v = 0;
    elseif v > 100 then
        v = 100
    end

    local it = inTable(animNames, anim:getName())
    if it ~= 0 then
        objVisibility[it] = v
        obj:setValue(VObjectVisibility, v)
    end
end

-- mouse event callback
function mouseEvents(eventType, mousePosition)
    if eventType == eEvtMouseLeftButtonDown then
        selectedObject = game:getLink(VGameCurrentObject)
        -- there is an object beneath the cursor and it is of type eObjects
        if selectedObject ~= nil and selectedObject:getId().tableId == eObjects then
            -- only move objects with a movable == true condition
            local cond = selectedObject:getObject('.ObjectConditions[movable]')
            if cond == nil or not cond:getBool(VConditionValue) then
                return
            end
            selectedAnim = getObject("ActiveAnimations["..selectedObject:getName().."_Anim]")
            local it = inTable(animNames, selectedAnim:getName())
            -- the first time this element was selected ??? it == 0 means yes
            if it == 0 then
                table.insert(animNames, selectedAnim:getName())
                table.insert(animPositions, selectedAnim:getPoint(VAnimationCurrentPosition))
                table.insert(objVisibility, selectedObject:getInt(VObjectVisibility))
            end
            leftMouseButtonIsPressed = 1
            -- remember the position where the left button was pressed
            firstMousePosition = mousePosition
        end
    -- eEvtMouseLeftButtonUp and eEvtMouseLeftButtonHold are left-button-released events
    elseif eventType == eEvtMouseLeftButtonUp or eventType == eEvtMouseLeftButtonHold then
        -- is there anything to do
        if leftMouseButtonIsPressed == 1 then
            leftMouseButtonIsPressed = 0
            -- change the selected object's polygon
            modifyObjectsPolygon(selectedObject, {x=mousePosition.x - firstMousePosition.x, y=mousePosition.y - firstMousePosition.y})

            -- save the selected object's animation position
            local it = inTable(animNames, selectedAnim:getName())
            animPositions[it] = selectedAnim:getPoint(VAnimationCurrentPosition)

            -- initiate a scene reload
            local currentScene = game:getLink(VGameCurrentScene)
            if currentScene ~= nil then
                reloadSceneAction = currentScene:getObject(".SceneActions[reloadScene]")
                startAction(reloadSceneAction)
            end
            selectedObject = nil
            selectedAnim = nil
        end
    elseif eventType == eEvtMouseMove then
        mouseMove(mousePosition)
    elseif eventType == eEvtMouseWheelUp then
        addVisibility(5)
    elseif eventType == eEvtMouseWheelDown then
        addVisibility(-5)
    end
end

-- called from reloadSceneAction
-- After a scene reload move all animations to the position we left them and set there visibility
function setSelectedAnimPos()
    local currentScene = game:getLink(VGameCurrentScene)
    if currentScene ~= nil then
        local sceneObjects = currentScene:getLinks(VSceneObjects)
        for i=1,table.maxn(sceneObjects) do
            local anim = getObject("ActiveAnimations["..sceneObjects[i]:getName().."_Anim]")
            if anim ~= nil then
                local it = inTable(animNames, anim:getName())
                if it ~= 0 then
                    setAnimToPosition(anim, animPositions[it])
                    sceneObjects[i]:setValue(VObjectVisibility, objVisibility[it])
                end
            end
        end
    end
end

function init()
    registerEventHandler("mouseEvent", "mouseEvents", {eEvtMouseMove, eEvtMouseLeftButtonDown, eEvtMouseLeftButtonUp, eEvtMouseLeftButtonHold, eEvtMouseWheelUp, eEvtMouseWheelDown})
end