commonMain.de.fabmax.kool.physics.joints.RevoluteJoint.kt Maven / Gradle / Ivy

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A multiplatform OpenGL / Vulkan graphics engine written in kotlin

There is a newer version: 0.15.1

package de.fabmax.kool.physics.joints

import de.fabmax.kool.math.*
import de.fabmax.kool.physics.RigidActor

expect fun RevoluteJoint(bodyA: RigidActor, bodyB: RigidActor, frameA: Mat4f, frameB: Mat4f): RevoluteJoint

expect fun RevoluteJoint(bodyA: RigidActor, bodyB: RigidActor, pivotA: Vec3f, pivotB: Vec3f, axisA: Vec3f, axisB: Vec3f): RevoluteJoint

interface RevoluteJoint : Joint {
    fun disableAngularMotor()
    fun enableAngularMotor(angularVelocity: Float, forceLimit: Float)

    companion object {
        fun computeFrame(pivot: Vec3f, axis: Vec3f): Mat4f {
            val ax1 = MutableVec3f()
            val ax2 = MutableVec3f()

            val dot = axis.dot(Vec3f.X_AXIS)
            when {
                dot >= 1.0f - FLT_EPSILON -> {
                    ax1.set(Vec3f.Z_AXIS)
                    ax2.set(Vec3f.Y_AXIS)
                }
                dot <= -1.0f + FLT_EPSILON -> {
                    ax1.set(Vec3f.NEG_Z_AXIS)
                    ax2.set(Vec3f.NEG_Y_AXIS)
                }
                else -> {
                    axis.cross(Vec3f.X_AXIS, ax2)
                    axis.cross(ax2, ax1)
                }
            }

            val frame = MutableMat4f()
            frame.translate(pivot)
            frame.setColumn(0, axis, 0f)
            frame.setColumn(1, ax2.norm(), 0f)
            frame.setColumn(2, ax1.norm(), 0f)
            return frame
        }
    }
}