commonMain.ru.casperix.math.geometry.float32.WindingOrder.kt Maven / Gradle / Ivy

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

import ru.casperix.math.angle.float32.RadianFloat
import ru.casperix.math.collection.getLooped
import ru.casperix.math.geometry.Polygon2f
import ru.casperix.math.geometry.RotateDirection
import ru.casperix.math.vector.float32.Vector2f
import kotlin.math.PI

fun Polygon2f.getWindingOrder(): RotateDirection {
    val vertices = getVertices()

    var accumulatedAngle = RadianFloat.ZERO
    vertices.indices.forEach {
        accumulatedAngle += getWindingAngle(vertices, it)
    }

    return getWindingOrder(accumulatedAngle)
}

fun getWindingAngle(vertices: List, vertexIndex: Int): RadianFloat {
    val last = vertices.getLooped(vertexIndex - 1)
    val current = vertices.getLooped(vertexIndex)
    val next = vertices.getLooped(vertexIndex + 1)
    val directedAngle = RadianFloat.betweenDirectionsDirected(current - last, current-next)
    return directedAngle - RadianFloat.PI
}

fun getWindingOrder(angle: RadianFloat): RotateDirection {
    return if (angle >= RadianFloat.ZERO) {
        RotateDirection.COUNTERCLOCKWISE
    } else {
        RotateDirection.CLOCKWISE
    }
}

fun getWindingOrder(vertices: List, vertexIndex: Int): RotateDirection {
    return getWindingOrder(getWindingAngle(vertices, vertexIndex))
}