Vital.sandbox

util.easing.lerp

Shared

Linearly interpolates between two values by a progress factor


Syntax

local result = util.easing.lerp(
    from,
    to,
    progress
)

util.easing.lerp is the standard pairing for all easing functions.

  • Pair with any easing curve — wrap progress in any util.easing.* function to drive the interpolation.
  • Best for — animating positions, sizes, colors, or any numeric value between two points.

Parameters

TypeNameDescription
floatfromStart value
floattoEnd value
floatprogressInterpolation factor, typically in the range [0, 1]

Returns

TypeNameDescription
floatresultInterpolated value between from and to

Examples

Interpolate between 0 and 100 at 50%
local result = util.easing.lerp(0, 100, 0.5)

core.engine.print("info", result) -- 50.0
Pair with an easing curve
local result = util.easing.lerp(0, 100, util.easing.cubic_in_out(0.5))

core.engine.print("info", result)
Animate a value across the screen
local resolution = core.engine.get_resolution()
local duration = 2.0
local start_tick = core.engine.get_tick()

util.event.on("sandbox:draw", function()
    local elapsed = (core.engine.get_tick() - start_tick) / 1000.0
    local t = math.min(elapsed / duration, 1.0)
    local x = util.easing.lerp(0, resolution[1], util.easing.sine_in_out(t))

    core.engine.draw_circle({x, resolution[2]*0.5}, 16, {1, 1, 1, 1})
end)

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SyntaxParametersReturnsExamples