Plasma effect

Plasma effect is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.

The plasma effect is a visual effect created by applying various functions, notably sine and cosine, to the color values of screen pixels. When animated the effect may give the impression of a colorful flowing liquid.

The task: create a plasma effect.

See also

• Computer Graphics Tutorial (lodev.org)
• Plasma (bidouille.org)

Java

Works with: Java version 8

<lang java>import java.awt.*; import java.awt.event.*; import java.awt.image.*; import static java.awt.image.BufferedImage.*; import static java.lang.Math.*; import javax.swing.*;

public class PlasmaEffect extends JPanel {

   float[][] plasma;
   float hueShift = 0;
   BufferedImage img;

   public PlasmaEffect() {
       Dimension dim = new Dimension(640, 640);
       setPreferredSize(dim);
       setBackground(Color.white);

       img = new BufferedImage(dim.width, dim.height, TYPE_INT_RGB);
       plasma = createPlasma(dim.height, dim.width);

       // animate about 24 fps and shift hue value with every frame
       new Timer(42, (ActionEvent e) -> {
           hueShift = (hueShift + 0.02f) % 1;
           repaint();
       }).start();
   }

   float[][] createPlasma(int w, int h) {
       float[][] buffer = new float[h][w];

       for (int y = 0; y < h; y++)
           for (int x = 0; x < w; x++) {

               double value = sin(x / 16.0);
               value += sin(y / 8.0);
               value += sin((x + y) / 16.0);
               value += sin(sqrt(x * x + y * y) / 8.0);
               value += 4; // shift range from -4 .. 4 to 0 .. 8
               value /= 8; // bring range down to 0 .. 1

               // requires VM option -ea
               assert (value >= 0.0 && value <= 1.0) : "Hue value out of bounds";

               buffer[y][x] = (float) value;
           }
       return buffer;
   }

   void drawPlasma(Graphics2D g) {
       int h = plasma.length;
       int w = plasma[0].length;
       for (int y = 0; y < h; y++)
           for (int x = 0; x < w; x++) {
               float hue = hueShift + plasma[y][x] % 1;
               img.setRGB(x, y, Color.HSBtoRGB(hue, 1, 1));
           }
       g.drawImage(img, 0, 0, null);
   }

   @Override
   public void paintComponent(Graphics gg) {
       super.paintComponent(gg);
       Graphics2D g = (Graphics2D) gg;
       g.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
               RenderingHints.VALUE_ANTIALIAS_ON);

       drawPlasma(g);
   }

   public static void main(String[] args) {
       SwingUtilities.invokeLater(() -> {
           JFrame f = new JFrame();
           f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
           f.setTitle("Plasma Effect");
           f.setResizable(false);
           f.add(new PlasmaEffect(), BorderLayout.CENTER);
           f.pack();
           f.setLocationRelativeTo(null);
           f.setVisible(true);
       });
   }

}</lang>