kotlin-apps: add the HelloVehicle0 app

kotlin-apps/build.gradle

@@ -39,6 +39,9 @@ ext {
 tasks.register('HelloLibbulletjme', JavaExec) {
     mainClass = 'com.github.stephengold.lbjexamples.ktapps.console.HelloLibbulletjmeKt'
 }
+tasks.register('HelloVehicle0', JavaExec) {
+    mainClass = 'com.github.stephengold.lbjexamples.ktapps.console.HelloVehicle0Kt'
+}
 
 import org.gradle.nativeplatform.platform.internal.DefaultNativePlatform
 OperatingSystem os = DefaultNativePlatform.currentOperatingSystem

kotlin-apps/src/main/kotlin/com/github/stephengold/lbjexamples/ktapps/console/HelloVehicle0.kt

@@ -0,0 +1,130 @@
+/*
+ Copyright (c) 2024 Stephen Gold and Yanis Boudiaf
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions are met:
+
+ 1. Redistributions of source code must retain the above copyright notice, this
+    list of conditions and the following disclaimer.
+
+ 2. Redistributions in binary form must reproduce the above copyright notice,
+    this list of conditions and the following disclaimer in the documentation
+    and/or other materials provided with the distribution.
+
+ 3. Neither the name of the copyright holder nor the names of its
+    contributors may be used to endorse or promote products derived from
+    this software without specific prior written permission.
+
+ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package com.github.stephengold.lbjexamples.ktapps.console
+
+import com.jme3.bullet.PhysicsSpace
+import com.jme3.bullet.collision.shapes.CollisionShape
+import com.jme3.bullet.collision.shapes.HullCollisionShape
+import com.jme3.bullet.collision.shapes.PlaneCollisionShape
+import com.jme3.bullet.objects.PhysicsBody
+import com.jme3.bullet.objects.PhysicsRigidBody
+import com.jme3.bullet.objects.PhysicsVehicle
+import com.jme3.math.FastMath
+import com.jme3.math.Plane
+import com.jme3.math.Vector3f
+import com.jme3.system.NativeLibraryLoader
+import java.io.File
+import java.util.ArrayList
+import java.util.Collection
+
+/*
+ * Drive a vehicle on a horizontal surface (non-graphical illustrative example).
+ *
+ * author: Stephen Gold [email protected]
+ */
+
+/*
+ * Main entry point for the HelloVehicle0 application.
+ */
+fun main() {
+    // Load a native library from ~/Downloads directory.
+    val homePath = System.getProperty("user.home")
+    val downloadDirectory = File(homePath, "Downloads")
+    NativeLibraryLoader.loadLibbulletjme(
+        true, downloadDirectory, "Release", "Sp")
+
+    // Create a PhysicsSpace using DBVT for broadphase.
+    val physicsSpace = PhysicsSpace(PhysicsSpace.BroadphaseType.DBVT)
+
+    // Add a  horizontal plane at y=-0.65 to represent the ground.
+    val groundY = -0.65f
+    val plane = Plane(Vector3f.UNIT_Y, groundY)
+    val planeShape = PlaneCollisionShape(plane)
+    var mass = PhysicsBody.massForStatic
+    val floor = PhysicsRigidBody(planeShape, mass)
+    physicsSpace.addCollisionObject(floor)
+
+    // Create a wedge-shaped vehicle with a low center of gravity.
+    // The local forward direction is +Z.
+    val noseZ = 1.4f           // offset from chassis center
+    val spoilerY = 0.5f        // offset from chassis center
+    val tailZ = -0.7f          // offset from chassis center
+    val undercarriageY = -0.1f // offset from chassis center
+    val halfWidth = 0.4f
+    val cornerLocations = ArrayList<Vector3f>(6)
+    cornerLocations.add(Vector3f(+halfWidth, undercarriageY, noseZ))
+    cornerLocations.add(Vector3f(-halfWidth, undercarriageY, noseZ))
+    cornerLocations.add(Vector3f(+halfWidth, undercarriageY, tailZ))
+    cornerLocations.add(Vector3f(-halfWidth, undercarriageY, tailZ))
+    cornerLocations.add(Vector3f(+halfWidth, spoilerY, tailZ))
+    cornerLocations.add(Vector3f(-halfWidth, spoilerY, tailZ))
+    val wedgeShape = HullCollisionShape(cornerLocations)
+    mass = 5f
+    val vehicle = PhysicsVehicle(wedgeShape, mass)
+    vehicle.setSuspensionCompression(6f) // default=0.83
+    vehicle.setSuspensionDamping(7f) // default=0.88
+    vehicle.setSuspensionStiffness(150f) // default=5.88
+
+    // Add 4 wheels, 2 in the front (for steering) and 2 in the rear.
+    val front = true
+    val rear = false
+    val frontAxisZ = 0.7f * noseZ // offset from chassis center
+    val rearAxisZ = 0.8f * tailZ // offset from chassis center
+    val radius = 0.3f // of each tire
+    val restLength = 0.2f // of the suspension
+    val xOffset = 0.9f * halfWidth
+    val axleDirection = Vector3f(-1f, 0f, 0f)
+    val suspensionDirection = Vector3f(0f, -1f, 0f)
+    vehicle.addWheel( Vector3f(-xOffset, 0f, frontAxisZ),
+            suspensionDirection, axleDirection, restLength, radius, front)
+    vehicle.addWheel( Vector3f(xOffset, 0f, frontAxisZ),
+            suspensionDirection, axleDirection, restLength, radius, front)
+    vehicle.addWheel( Vector3f(-xOffset, 0f, rearAxisZ),
+            suspensionDirection, axleDirection, restLength, radius, rear)
+    vehicle.addWheel( Vector3f(xOffset, 0f, rearAxisZ),
+            suspensionDirection, axleDirection, restLength, radius, rear)
+
+    physicsSpace.addCollisionObject(vehicle)
+
+    // Apply a steering angle of 6 degrees left (to the front wheels).
+    vehicle.steer(FastMath.PI / 30f)
+
+    // Apply a constant acceleration (to the chassis).
+    vehicle.accelerate(1f)
+
+    // 150 iterations with a 16.7-msec timestep
+    val timeStep = 1 / 60f
+    val maxSteps = 0
+    val location = Vector3f()
+    for (i in 0 ..< 150) {
+        physicsSpace.update(timeStep, maxSteps)
+        vehicle.getPhysicsLocation(location)
+        println(location)
+    }
+}