commonMain.ru.casperix.math.curve.float32.Bezier2f.kt Maven / Gradle / Ivy

Go to download
package ru.casperix.math.curve.float32

import ru.casperix.math.curve.CurveHelper
import ru.casperix.math.interpolation.float32.InterpolationFloat
import ru.casperix.math.vector.float32.Vector2f
import ru.casperix.misc.clamp
import kotlinx.serialization.Serializable
import kotlin.math.roundToInt

@Serializable
class Bezier2f(val points: List) : ParametricCurve2f {
    init {
        if (points.isEmpty()) throw Error("Curve must contains points")
    }

    override fun divide(t: Float): Pair {
        TODO("Not yet implemented")
    }

    override fun getPosition(t: Float): Vector2f {
        val segments = points.size - 1

        if (segments == 0) {
            return points[0]
        }
        if (segments == 1) {
            return InterpolationFloat.vector2(points[0], points[1], t)
        }

        val factor = segments * t.clamp(0f, 1f)
        val index = factor.roundToInt()
        val fract = factor - index.toFloat() + 0.5f

        val main = points[index]
        var last = points.getOrNull(index - 1)
        var next = points.getOrNull(index + 1)

        if (last == null) {
            val dir = next!! - main
            last = main - dir
        }

        if (next == null) {
            val dir = last!! - main
            next = main - dir
        }


        val a = (last + main) / 2f
        val b = main
        val c = (next + main) / 2f

        return BezierQuadratic2f(a, b, c).getPosition(fract)
    }

    override fun length(): Float {
        return CurveHelper.calculateLength(this, 10)
    }
}