Difference between revisions of "BezierCurve:evaluate"
(A better example. (The old example did exactly what BezierCurve:render is for.)) |
(Undo revision 27963 by Darkfrei (talk). Mention the control point requirement in the description instead.) (Tag: Undo) |
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{{newin|[[0.9.0]]|090|type=function}} | {{newin|[[0.9.0]]|090|type=function}} | ||
| − | Evaluate Bézier curve at parameter t. The parameter must be between 0 and 1 (inclusive). | + | Evaluate Bézier curve at parameter t. The parameter must be between 0 and 1 (inclusive) and there must be at least two control points for the curve. |
| − | This function can be used to move objects along paths or tween parameters. However it should not be used to render the curve | + | This function can be used to move objects along paths or tween parameters. However it should not be used to render the curve - see [[BezierCurve:render]] for that purpose. |
== Function == | == Function == | ||
=== Synopsis === | === Synopsis === | ||
<source lang="lua"> | <source lang="lua"> | ||
| − | x,y = BezierCurve:evaluate(t) | + | x, y = BezierCurve:evaluate( t ) |
</source> | </source> | ||
=== Arguments === | === Arguments === | ||
| − | {{param|number|t|Where to evaluate the curve.}} | + | {{param|number|t|Where to evaluate the curve. Must be between 0 and 1.}} |
=== Returns === | === Returns === | ||
{{param|number|x|x coordinate of the curve at parameter t.}} | {{param|number|x|x coordinate of the curve at parameter t.}} | ||
| Line 18: | Line 18: | ||
=== Make a circle follow a curve === | === Make a circle follow a curve === | ||
<source lang="lua"> | <source lang="lua"> | ||
| − | local | + | local controlPoints = {125,125, 125,225, 175,125, 225,125} |
| + | local curve = love.math.newBezierCurve(controlPoints) | ||
function love.draw() | function love.draw() | ||
Latest revision as of 17:07, 14 August 2022
| Available since LÖVE 0.9.0 |
| This function is not supported in earlier versions. |
Evaluate Bézier curve at parameter t. The parameter must be between 0 and 1 (inclusive) and there must be at least two control points for the curve.
This function can be used to move objects along paths or tween parameters. However it should not be used to render the curve - see BezierCurve:render for that purpose.
Contents
Function
Synopsis
x, y = BezierCurve:evaluate( t )
Arguments
number t- Where to evaluate the curve. Must be between 0 and 1.
Returns
number x- x coordinate of the curve at parameter t.
number y- y coordinate of the curve at parameter t.
Examples
Make a circle follow a curve
local controlPoints = {125,125, 125,225, 175,125, 225,125}
local curve = love.math.newBezierCurve(controlPoints)
function love.draw()
local time = love.timer.getTime()
local loopTime = 4
local t = (time / loopTime) % 1
local x, y = curve:evaluate(t)
love.graphics.circle("fill", x, y, 8)
love.graphics.line(curve:render())
end
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