InterpolateBetween

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Interpolates a 3D Vector between a source value and a target value using either linear interpolation or any other easing function. It can also be used to interpolate 2D vectors or scalars by only setting some of the x, y, z values and putting 0 to the others.

Syntax

float float float interpolateBetween ( float x1, float y1, float z1, float x2, float y2, float z2, float fProgress, string strEasingType, [ float fEasingPeriod, float fEasingAmplitude, float fEasingOvershoot ] )

Required Arguments

  • x1, y1, z1: 3D coordinates of source vector/value
  • x2, y2, z2: 3D coordinates of target vector/value
  • fProgress: float between 0 and 1 indicating the interpolation progress (0 at the beginning of the interpolation, 1 at the end).
  • strEasingType: the easing function to use for the interpolation

Optional Arguments

  • fEasingPeriod: the period of the easing function (only some easing functions use this parameter)
  • fEasingAmplitude: the amplitude of the easing function (only some easing functions use this parameter)
  • fEasingOvershoot: the overshoot of the easing function (only some easing functions use this parameter)

Returns

Returns x, y, z the interpolated 3D vector/value if successful, false otherwise (error in parameters). As mentioned before, interpolateBetween can be used on 2D vectors or scalars in which case only some (x, y or just x) of the returned values are to be used (cf. alpha interpolation in marker example or size interpolation in window example).

Examples

The examples below are only clientside examples even though the function can be used on both sides. Indeed it makes more sense to use it with onClientRender/onClientPreRender but the freedom is given to use it in any other context.

Click to collapse [-]
Client

This clientside example uses interpolateBetween to create position and color interpolation(with effect) on a marker. The command to test it is "/marker". The position is interpolated with "OutBounce" as strEasingType to make the marker bounce off the ground and "Linear" interpolation for the color.

local g_Marker = nil
addCommandHandler("marker",
function ()
	if g_Marker then return end
	
	local x, y, z = getElementPosition(getLocalPlayer())
	z = z - 1
	
	g_Marker = {}
	g_Marker.startPos = {x, y, z + 5}
	g_Marker.startTime = getTickCount()
	g_Marker.startColor = {255, 0, 0, 0}
	g_Marker.endPos = {x, y, z}
	g_Marker.endTime = g_Marker.startTime + 2000
	g_Marker.endColor = {0, 0, 255, 255}	
	
	local x, y, z = unpack(g_Marker.startPos)
	local r, g, b, a = unpack(g_Marker.startColor)
	g_Marker.marker = createMarker(x, y, z, "cylinder", 1, 255, r, g, b, a)
		
	addEventHandler("onClientRender", getRootElement(), popMarkerUp)
end)

function popMarkerUp()
	local now = getTickCount()
	local elapsedTime = now - g_Marker.startTime
	local duration = g_Marker.endTime - g_Marker.startTime
	local progress = elapsedTime / duration

	local x1, y1, z1 = unpack(g_Marker.startPos)
	local x2, y2, z2 = unpack(g_Marker.endPos)
	local x, y, z = interpolateBetween ( 
		x1, y1, z1,
		x2, y2, z2, 
		progress, "OutBounce")
		
	setElementPosition(g_Marker.marker, x, y, z)
			
	local r1, g1, b1, a1 = unpack(g_Marker.startColor)
	local r2, g2, b2, a2 = unpack(g_Marker.endColor)
	local r, g, b = interpolateBetween ( 
		r1, g1, b1,
		r2, g2, b2, 
		progress, "Linear")
	local a = interpolateBetween ( 
		a1, 0, 0,
		a2, 0, 0,
		progress, "Linear")
		
	setMarkerColor(g_Marker.marker , r, g, b, a)
	
	if now >= g_Marker.endTime then
		removeEventHandler("onClientRender", getRootElement(), popMarkerUp)
		setTimer(
			function ()
				destroyElement(g_Marker.marker)
				g_Marker = nil
			end, 3000, 1)
	end
end
Click to collapse [-]
Client

This clientside example uses interpolateBetween to create size and position interpolation (with effect) on a gui-window. The command to test it is "/window". When the window pops up it uses "OutElastic" as the strEasingType to create the bouncing/elastic effect. When it fades away, it uses "InQuad" to have an accelerating fading.

local g_Window = nil
addCommandHandler("window",
function ()
	if g_Window then return end
	
	g_Window = {}
	
	local screenWidth, screenHeight = guiGetScreenSize()
	g_Window.windowWidth, g_Window.windowHeight = 400, 315
	local left = screenWidth/2 - g_Window.windowWidth/2
	local top = screenHeight/2 - g_Window.windowHeight/2
	
	g_Window.window = guiCreateWindow(left, top, g_Window.windowWidth, g_Window.windowHeight, "Interpolation on GUI", false)
	
	g_Window.closeBtn = guiCreateButton(320, 285, 75, 23, "Close", false, g_Window.window)
		
	guiWindowSetSizable(g_Window.window, false)
	guiWindowSetMovable(g_Window.window, false)
	guiSetEnabled(g_Window.window, false)
	guiSetVisible(g_Window.window, false)
	
	g_Window.startTime = getTickCount()
	g_Window.startSize = {0, 0}
	g_Window.endSize = {g_Window.windowWidth, g_Window.windowHeight}
	g_Window.endTime = g_Window.startTime + 1000
	addEventHandler("onClientRender", getRootElement(), popWindowUp)
end)

function on_closeBtn_clicked(button, state, absoluteX, absoluteY)
	if (button ~= "left") or (state ~= "up") then
		return
	end
	
	if not g_Window then return end
	
	showCursor(false)
	guiSetEnabled(g_Window.window, false)
	guiWindowSetMovable(g_Window.window, false)
	
	local screenWidth, screenHeight = guiGetScreenSize()
	local posX, posY = guiGetPosition(g_Window.window, false)
	
	g_Window.startTime = getTickCount()
	g_Window.startSize = {g_Window.windowWidth, g_Window.windowHeight}
	g_Window.startCenter = 
	{
		posX + g_Window.windowWidth/2,
		posY + g_Window.windowHeight/2,
	}
	
	g_Window.endSize = {0, 0}
	g_Window.endTime = g_Window.startTime + 1000
	g_Window.endCenter = 
	{
		screenWidth, 
		screenHeight
	}
	
	addEventHandler("onClientRender", getRootElement(), popWindowDown)
end

function popWindowUp()
	local now = getTickCount()
	local elapsedTime = now - g_Window.startTime
	local duration = g_Window.endTime - g_Window.startTime
	local progress = elapsedTime / duration
		
	local width, height, _ = interpolateBetween ( 
		g_Window.startSize[1], g_Window.startSize[2], 0, 
		g_Window.endSize[1], g_Window.endSize[2], 0, 
		progress, "OutElastic")
		
	guiSetSize(g_Window.window, width, height, false)
	
	local screenWidth, screenHeight = guiGetScreenSize()
	guiSetPosition(g_Window.window, screenWidth/2 - width/2, screenHeight/2 - height/2, false)
	
	if not guiGetVisible(g_Window.window) then
		guiSetVisible(g_Window.window, true)
		guiBringToFront(g_Window.window)
	end
	
	if now >= g_Window.endTime then
		guiSetEnabled(g_Window.window, true)
		
		guiBringToFront(g_Window.window)
		removeEventHandler("onClientRender", getRootElement(), popWindowUp)
		addEventHandler("onClientGUIClick", g_Window.closeBtn, on_closeBtn_clicked, false)
		showCursor(true)
		guiWindowSetMovable(g_Window.window, true)
	end
end

function popWindowDown()
	local now = getTickCount()
	local elapsedTime = now - g_Window.startTime
	local duration = g_Window.endTime - g_Window.startTime
	local progress = elapsedTime / duration
	
	local width, height, _ = interpolateBetween ( 
		g_Window.startSize[1], g_Window.startSize[2], 0, 
		g_Window.endSize[1], g_Window.endSize[2], 0, 
		progress, "InQuad")
		
	guiSetSize(g_Window.window, width, height, false)
	
	local centerX, centerY, _ = interpolateBetween ( 
		g_Window.startCenter[1], g_Window.startCenter[2], 0, 
		g_Window.endCenter[1], g_Window.endCenter[2], 0, 
		progress, "InQuad")
	
	guiSetPosition(g_Window.window, centerX - width/2, centerY - height/2, false)
	
	if now >= g_Window.endTime then
		removeEventHandler("onClientRender", getRootElement(), popWindowDown)
		destroyElement(g_Window.window)
		g_Window = nil
	end
end

Click to collapse [-]
Client

This clientside example uses interpolateBetween to create and position interpolation (with effect) on a camera. The command to test it is "/ccam". When the camera pops up it uses "OutQuad" as the strEasingType to create the slow down effect.

local enabled = false
 
addCommandHandler("ccam", function()
    enabled = not enabled
    if enabled then
        start = getTickCount()
        dx, dy, dz, lx, ly, lz = getCameraMatrix()
        addEventHandler("onClientPreRender", root, interpolateCam)
        else
        start = nil
        setCameraTarget(localPlayer)
        removeEventHandler("onClientPreRender", root, interpolateCam)
    end
end)
 
function interpolateCam()
    local now = getTickCount()
    local endTime = start + 2000
    local elapsedTime = now - start
    local duration = endTime - start
    local progress = elapsedTime / duration
    local px, py, pz = getElementPosition(localPlayer)
    local x, y, z = interpolateBetween ( dx, dy, dz, dx+4, dy+4, dz, progress, "OutQuad")
    setCameraMatrix(x, y, z, px, py, pz+0.6, 0, 0)
end

See Also