Completed Chapter 15

Author: HarryDulaney

ch_15/Exercise15_33.java

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+package ch_15;
+
+import javafx.animation.PathTransition;
+import javafx.application.Application;
+import javafx.collections.ObservableList;
+import javafx.geometry.Point2D;
+import javafx.scene.Scene;
+import javafx.scene.layout.Pane;
+import javafx.scene.paint.Color;
+import javafx.scene.shape.Circle;
+import javafx.scene.shape.Line;
+import javafx.scene.shape.Polyline;
+import javafx.stage.Stage;
+import javafx.util.Duration;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * ***15.33 (Game: bean-machine animation) Write a program that animates the bean
+ * machine introduced in Programming Exercise 7.21. The animation terminates
+ * after ten balls are dropped, as shown in Figure 15.36b and c.
+ */
+public class Exercise15_33 extends Application {
+
+    @Override
+    public void start(Stage primaryStage) {
+        double WIDTH = 400;
+        double HEIGHT = 400;
+        BeanMachinePane pane = new BeanMachinePane(WIDTH, HEIGHT, 8);
+        Scene scene = new Scene(pane, WIDTH, HEIGHT);
+        primaryStage.setScene(scene);
+        primaryStage.setResizable(false);
+        primaryStage.setTitle(getClass().getName());
+        primaryStage.show();
+        playAnimation(pane);
+    }
+
+    static void playAnimation(BeanMachinePane pane) {
+        /* Drop 10 balls */
+        for (int i = 0; i < 10; i++) {
+            pane.dropBall();
+        }
+    }
+
+    static class BeanMachinePane extends Pane {
+        private final int numberOfPins;
+        private final int numberOfSlots;
+
+        double ballRadius;
+
+        Line[] outlineShape;
+        Line outlineShapeBaseLine;
+        Line[] slotVerticalLines;
+        Circle[] pins;
+
+        List<Circle> droppedBalls = new ArrayList<>();
+
+        double spaceBallDropDelaySeconds = 0.5;
+
+        public BeanMachinePane(double width, double height, int numberOfSlots) {
+            setWidth(width);
+            setHeight(height);
+            this.numberOfSlots = numberOfSlots;
+            this.numberOfPins = getNumberOfPins(numberOfSlots);
+            buildStaticShapes();
+            getChildren().add(outlineShapeBaseLine);
+            getChildren().addAll(outlineShape);
+            getChildren().addAll(slotVerticalLines);
+            getChildren().addAll(pins);
+        }
+
+        public void dropBall() {
+            ballDropAnimation();
+        }
+
+        private void ballDropAnimation() {
+            /* Draw ball in the center flask shape opening */
+            double flaskOpeningCenterX = getDropStartPtX();
+            /* Draw ball just ABOVE flask shape opening */
+            ballRadius = pins[0].getRadius();
+            Circle ball = new Circle(flaskOpeningCenterX,
+                    outlineShape[5].getEndY() - ballRadius - 20,
+                    ballRadius,
+                    Color.RED);
+            Polyline polyline = createRandomPath(ball);
+            PathTransition path = new PathTransition(Duration.seconds(4), polyline, ball);
+            path.setDelay(Duration.seconds(spaceBallDropDelaySeconds));
+            spaceBallDropDelaySeconds += 1.5;
+            getChildren().addAll(polyline);
+            getChildren().addAll(ball);
+            droppedBalls.add(ball);
+            path.play();
+        }
+
+        private double getDropStartPtX() {
+            return outlineShapeBaseLine.getStartX()
+                    + (outlineShapeBaseLine.getEndX()
+                    - outlineShapeBaseLine.getStartX()) / 2;
+        }
+
+
+        private Line getBaseLineShape(double paneWidth, double paneHeight) {
+            /* Horizontal line at the bottom of the machine (Y value does not change) */
+            double baseLineYValue = paneHeight * 0.8;
+            double baseLineStartXValue = paneWidth * 0.2;
+            double baseLineEndXValue = paneWidth * 0.8;
+            return new Line(baseLineStartXValue, baseLineYValue, baseLineEndXValue, baseLineYValue);
+
+        }
+
+
+        /**
+         * @param slots the number of slots in the bean machine
+         * @return the number of pins in the bean machine
+         */
+        int getNumberOfPins(int slots) {
+            int numPins = 0;
+            do {
+                slots--;
+                numPins += slots;
+            } while (slots > 1);
+
+            return numPins;
+        }
+
+        private void buildStaticShapes() {
+            double paneWidth = getWidth();
+            double paneHeight = getHeight();
+            outlineShapeBaseLine = getBaseLineShape(paneWidth, paneHeight);
+            double distance = (outlineShapeBaseLine.getEndX() - outlineShapeBaseLine.getStartX()) / numberOfSlots;
+            pins = new Circle[numberOfPins];
+            int index = 0;
+            for (int i = 1; i < numberOfSlots; i++) {
+                double x = outlineShapeBaseLine.getStartX() + (i * distance * 0.50) + distance / 2;
+                double y = outlineShapeBaseLine.getStartY() - (distance * i) - distance / 2;
+                for (int j = 0; j < numberOfSlots - i; j++) {
+                    pins[index++] = new Circle(x, y, paneWidth * 0.012, Color.BLUE);
+                    x += distance;
+                }
+            }
+
+            distance = distance + (distance / 2) - pins[0].getRadius();
+            slotVerticalLines = new Line[numberOfSlots - 1];
+            for (int i = 0; i < numberOfSlots - 1; i++) {
+                double x1 = pins[i].getCenterX() + pins[i].getRadius() * Math.sin(Math.PI);
+                double y1 = pins[i].getCenterY() - pins[i].getRadius() * Math.cos(Math.PI);
+                slotVerticalLines[i] = new Line(x1, y1, x1, y1 + distance);
+
+            }
+
+            outlineShape = new Line[6];
+            outlineShape[0] = new Line(
+                    outlineShapeBaseLine.getEndX(), outlineShapeBaseLine.getEndY(),
+                    outlineShapeBaseLine.getEndX(), outlineShapeBaseLine.getEndY() - distance);
+            outlineShape[1] = new Line(
+                    outlineShapeBaseLine.getStartX(), outlineShapeBaseLine.getStartY(),
+                    outlineShapeBaseLine.getStartX(), outlineShapeBaseLine.getStartY() - distance);
+
+            for (int i = 2; i < 4; i++) {
+                double x = pins[pins.length - i].getCenterX();
+                double y = pins[pins.length - i].getCenterY() - distance;
+                outlineShape[i] =
+                        new Line(x, y, outlineShape[i - 2].getEndX(), outlineShape[i - 2].getEndY());
+            }
+
+            for (int i = 4; i < outlineShape.length; i++) {
+                outlineShape[i] =
+                        new Line(
+                                outlineShape[i - 2].getStartX(),
+                                outlineShape[i - 2].getStartY(),
+                                outlineShape[i - 2].getStartX(),
+                                outlineShape[i - 2].getStartY() - (distance * 0.6)
+                        );
+            }
+        }
+
+        private Polyline createRandomPath(Circle ball) {
+            Polyline polyLine = new Polyline();
+            polyLine.setFill(Color.TRANSPARENT);
+            polyLine.setStroke(Color.TRANSPARENT);
+            ObservableList<Double> pathPoints = polyLine.getPoints();
+            Point2D startPoint = new Point2D(ball.getCenterX(), ball.getCenterY());
+            double nextX = startPoint.getX(); // Set current X to ball's center X starting position
+            double nextY = startPoint.getY(); // Set current Y to ball's center Y starting position
+            pathPoints.addAll(nextX, nextY);
+
+            while (nextY < outlineShapeBaseLine.getStartY() - ball.getRadius()) {
+                nextY += 1; // Move ball down on Y axis to simulate falling
+                /* Re-calculate random path until it does not pass through a static shape */
+                nextX = getRandomX(nextX);
+                while (collideWithPins(nextX, nextY) || collideWithOutline(nextX, nextY)) {
+                    nextX = getRandomX(nextX);
+                }
+                pathPoints.addAll(nextX, nextY);
+            }
+
+            return polyLine;
+        }
+
+        private boolean collideWithOutline(double nextX, double nextY) {
+            return false;
+        }
+
+        private boolean collideWithPins(double nextX, double nextY) {
+            for (Circle pin : pins) {
+                if (pin.contains(nextX, nextY + ballRadius)) {
+                    return true;
+                }
+            }
+            return false;
+        }
+
+        private double getRandomX(double currentX) {
+            double random = Math.random();
+            if (random < 0.5) {
+                currentX -= 1;
+            } else {
+                currentX += 1;
+            }
+            return currentX;
+        }
+
+
+    }
+}