kotlin-apps: add the HelloServer app

kotlin-apps/build.gradle

@@ -104,6 +104,10 @@ tasks.register('HelloRigidBody', JavaExec) {
     description = 'Runs the Kotlin version of the HelloRigidBody tutorial app.'
     mainClass = 'com.github.stephengold.lbjexamples.ktapps.HelloRigidBodyKt'
 }
+tasks.register('HelloServo', JavaExec) {
+    description = 'Runs the Kotlin version of the HelloServo tutorial app.'
+    mainClass = 'com.github.stephengold.lbjexamples.ktapps.HelloServoKt'
+}
 tasks.register('HelloSport', JavaExec) {
     description = 'Runs the Kotlin version of the HelloSport tutorial app.'
     mainClass = 'com.github.stephengold.lbjexamples.ktapps.HelloSportKt'

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

@@ -0,0 +1,242 @@
+/*
+ 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
+
+import com.github.stephengold.sport.Constants
+import com.github.stephengold.sport.input.CameraInputProcessor
+import com.github.stephengold.sport.input.InputProcessor
+import com.github.stephengold.sport.input.RotateMode
+import com.github.stephengold.sport.physics.BasePhysicsApp
+import com.github.stephengold.sport.physics.ConstraintGeometry
+import com.jme3.bullet.PhysicsSpace
+import com.jme3.bullet.RotationOrder
+import com.jme3.bullet.collision.shapes.BoxCollisionShape
+import com.jme3.bullet.collision.shapes.CapsuleCollisionShape
+import com.jme3.bullet.collision.shapes.CompoundCollisionShape
+import com.jme3.bullet.joints.JointEnd
+import com.jme3.bullet.joints.New6Dof
+import com.jme3.bullet.joints.motors.MotorParam
+import com.jme3.bullet.joints.motors.RotationMotor
+import com.jme3.bullet.objects.PhysicsRigidBody
+import com.jme3.math.Quaternion
+import com.jme3.math.Vector3f
+import org.lwjgl.glfw.GLFW
+
+/*
+ * A simple example of a PhysicsJoint with a servo.
+ *
+ * Builds upon HelloMotor.
+ *
+ * author:  Stephen Gold [email protected]
+ */
+
+/*
+ * Main entry point for the HelloServo application.
+ */
+fun main() {
+    val application = HelloServo()
+    application.start()
+}
+
+/*
+ * motor being tested
+ */
+private var motor: RotationMotor? = null
+
+class HelloServo : BasePhysicsApp<PhysicsSpace>() {
+    // *************************************************************************
+    // BasePhysicsApp override functions
+
+    /*
+     * Create the PhysicsSpace. Invoked once during initialization.
+     */
+    override fun createSpace(): PhysicsSpace {
+        val result = PhysicsSpace(PhysicsSpace.BroadphaseType.DBVT)
+
+        // For clarity, disable gravity.
+        result.setGravity(Vector3f.ZERO)
+
+        return result
+    }
+
+    /*
+     * Initialize the application. Invoked once.
+     */
+    override fun initialize() {
+        super.initialize()
+
+        configureCamera()
+        configureInput()
+        configureLighting()
+    }
+
+    /*
+     * Populate the PhysicsSpace. Invoked once during initialization.
+     */
+    override fun populateSpace() {
+        // Add a dynamic, green frame.
+        val frameBody = addFrame()
+
+        // Add a dynamic, yellow box for the door.
+        val doorBody = addDoor()
+
+        // Add a double-ended physics joint to join the door to the frame.
+        val pivotLocation = Vector3f(-1f, 0f, 0f)
+        val pivotOrientation = Quaternion.IDENTITY
+        val joint = New6Dof.newInstance(frameBody, doorBody,
+                pivotLocation, pivotOrientation, RotationOrder.XYZ)
+        physicsSpace.addJoint(joint)
+
+        val xRotationDof = 3 + PhysicsSpace.AXIS_X
+        val yRotationDof = 3 + PhysicsSpace.AXIS_Y
+        val zRotationDof = 3 + PhysicsSpace.AXIS_Z
+
+        // Lock the X and Z rotation DOFs.
+        joint.set(MotorParam.LowerLimit, xRotationDof, 0f)
+        joint.set(MotorParam.LowerLimit, zRotationDof, 0f)
+        joint.set(MotorParam.UpperLimit, xRotationDof, 0f)
+        joint.set(MotorParam.UpperLimit, zRotationDof, 0f)
+
+        // Limit the Y rotation DOF.
+        joint.set(MotorParam.LowerLimit, yRotationDof, 0f)
+        joint.set(MotorParam.UpperLimit, yRotationDof, 1.2f)
+
+        // Enable the motor for Y rotation.
+        motor = joint.getRotationMotor(PhysicsSpace.AXIS_Y)
+        motor!!.set(MotorParam.TargetVelocity, 0.4f)
+        motor!!.setMotorEnabled(true)
+        motor!!.setServoEnabled(true)
+
+        ConstraintGeometry(joint, JointEnd.A).setDepthTest(false)
+        ConstraintGeometry(joint, JointEnd.B).setDepthTest(false)
+    }
+    // *************************************************************************
+    // private functions
+
+    /*
+     * Create a dynamic rigid body with a box shape and add it to the space.
+     */
+    private fun addDoor(): PhysicsRigidBody {
+        val shape = BoxCollisionShape(0.8f, 0.8f, 0.1f)
+
+        val mass = 0.2f
+        val result = PhysicsRigidBody(shape, mass)
+        physicsSpace.addCollisionObject(result)
+
+        // Disable sleep (deactivation).
+        result.setEnableSleep(false)
+
+        visualizeShape(result)
+
+        return result
+    }
+
+    /*
+     * Create a dynamic body with a square-frame shape and add it to the space.
+     */
+    private fun addFrame(): PhysicsRigidBody {
+        val xShape = CapsuleCollisionShape(0.1f, 2f, PhysicsSpace.AXIS_X)
+        val yShape = CapsuleCollisionShape(0.1f, 2f, PhysicsSpace.AXIS_Y)
+
+        val frameShape = CompoundCollisionShape()
+        frameShape.addChildShape(xShape, 0f, +1f, 0f)
+        frameShape.addChildShape(xShape, 0f, -1f, 0f)
+        frameShape.addChildShape(yShape, +1f, 0f, 0f)
+        frameShape.addChildShape(yShape, -1f, 0f, 0f)
+
+        val result = PhysicsRigidBody(frameShape)
+        physicsSpace.addCollisionObject(result)
+        visualizeShape(result)
+
+        return result
+    }
+
+    /*
+     * Configure the Camera and CIP during startup.
+     */
+    private fun configureCamera() {
+        val cip = getCameraInputProcessor()
+        cip.setRotationMode(RotateMode.DragLMB)
+        cip.setMoveSpeed(5f)
+
+        cam.setLocation(Vector3f(0f, 1.5f, 4f))
+        cam.setAzimuth(-1.56f)
+        cam.setUpAngle(-0.45f)
+    }
+
+    /*
+     * Configure keyboard input during startup.
+     */
+    private fun configureInput() {
+        getInputManager().add(object : InputProcessor() {
+            override fun onKeyboard(glfwKeyId: Int, isPressed: Boolean) {
+                when (glfwKeyId) {
+                   GLFW.GLFW_KEY_1 -> {
+                        if (isPressed) {
+                            motor!!.set(MotorParam.ServoTarget, 1.2f)
+                        }
+                        return
+                    }
+
+                    GLFW.GLFW_KEY_2 -> {
+                        if (isPressed) {
+                            motor!!.set(MotorParam.ServoTarget, 0.8f)
+                        }
+                        return
+                    }
+
+                    GLFW.GLFW_KEY_3 -> {
+                        if (isPressed) {
+                            motor!!.set(MotorParam.ServoTarget, 0.4f)
+                        }
+                        return
+                    }
+
+                    GLFW.GLFW_KEY_4 -> {
+                        if (isPressed) {
+                            motor!!.set(MotorParam.ServoTarget, 0f)
+                        }
+                        return
+                    }
+                }
+                super.onKeyboard(glfwKeyId, isPressed)
+            }
+        })
+    }
+
+    /*
+     * Configure lighting and the background color.
+     */
+    private fun configureLighting() {
+        setLightDirection(7f, 3f, 5f)
+
+        // Set the background color to light blue.
+        setBackgroundColor(Constants.SKY_BLUE)
+    }
+}