Data commit

Task/Draw-a-rotating-cube/Scala/draw-a-rotating-cube.scala

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+import java.awt.event.ActionEvent
+import java.awt._
+
+import javax.swing.{JFrame, JPanel, Timer}
+
+import scala.math.{Pi, atan, cos, sin, sqrt}
+
+object RotatingCube extends App {
+
+  class RotatingCube extends JPanel {
+    private val vertices: Vector[Array[Double]] =
+      Vector(Array(-1, -1, -1), Array(-1, -1, 1), Array(-1, 1, -1),
+        Array(-1, 1, 1), Array(1, -1, -1), Array(1, -1, 1), Array(1, 1, -1), Array(1, 1, 1))
+
+    private val edges: Vector[(Int, Int)] =
+      Vector((0, 1), (1, 3), (3, 2), (2, 0), (4, 5), (5, 7),
+        (7, 6), (6, 4), (0, 4), (1, 5), (2, 6), (3, 7))
+
+    setPreferredSize(new Dimension(640, 640))
+    setBackground(Color.white)
+    scale(100)
+    rotateCube(Pi / 4, atan(sqrt(2)))
+
+    new Timer(17, (_: ActionEvent) => {
+      rotateCube(Pi / 180, 0)
+      repaint()
+    }).start()
+
+    override def paintComponent(gg: Graphics): Unit = {
+      def drawCube(g: Graphics2D): Unit = {
+        g.translate(getWidth / 2, getHeight / 2)
+        for {edge <- edges
+             xy1: Array[Double] = vertices(edge._1)
+             xy2: Array[Double] = vertices(edge._2)
+             } {
+          g.drawLine(xy1(0).toInt, xy1(1).toInt, xy2(0).toInt, xy2(1).toInt)
+          g.fillOval(xy1(0).toInt -4, xy1(1).toInt - 4, 8, 8)
+          g.setColor(Color.black)
+        }
+      }
+
+      super.paintComponent(gg)
+      val g: Graphics2D = gg.asInstanceOf[Graphics2D]
+      g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON)
+      drawCube(g)
+    }
+
+    private def scale(s: Double): Unit = {
+      for {node <- vertices
+           i <- node.indices
+           } node(i) *= s
+    }
+
+    private def rotateCube(angleX: Double, angleY: Double): Unit = {
+      def sinCos(x: Double) = (sin(x), cos(x))
+
+      val ((sinX, cosX), (sinY, cosY)) = (sinCos(angleX), sinCos(angleY))
+
+      for {
+        node <- vertices
+        x: Double = node(0)
+        y: Double = node(1)
+      } {
+        def f(p: Double, q: Double)(a: Double, b: Double) = a * p + b * q
+
+        def fx(a: Double, b: Double) = f(cosX, sinX)(a, b)
+
+        def fy(a: Double, b: Double) = f(cosY, sinY)(a, b)
+
+        node(0) = fx(x, -node(2))
+        val z = fx(node(2), x)
+        node(1) = fy(y, -z)
+        node(2) = fy(z, y)
+      }
+    }
+
+  }
+
+  new JFrame("Rotating Cube") {
+    add(new RotatingCube(), BorderLayout.CENTER)
+    pack()
+    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE)
+    setLocationRelativeTo(null)
+    setResizable(false)
+    setVisible(true)
+  }
+
+}