C:/Users/Andreas Schiffler/Desktop/SVN/NewGamePhysics/NewGamePhysics/GraphicalElements/GumowskiMiraFractal.cs


namespace NewGamePhysics.GraphicalElements
{
    using System;
    using Microsoft.Xna.Framework;
    using Microsoft.Xna.Framework.Graphics;

    public class GumowskiMiraFractal
    {
        private GraphicsDevice graphicsDevice;

        private int width;

        private int height;

        private byte[] imageBuffer;

        private Texture2D imageTexture;

        private double a;

        private double mu;

        private double x;

        private double y;

        private UInt32 iterations;

        private float scale = 0.02f;
        
        private Vector2 center = new Vector2();

        private float fw;

        private float fh;

        private float fwh;

        private float fhh;

        private double oldX1;
        
        private double oldY1;

        public GumowskiMiraFractal(GraphicsDevice graphicsDevice, int width, int height, double a, double mu, double x1, double y1)
        {
            // Store parameters
            this.graphicsDevice = graphicsDevice;
            this.width = width;
            this.height = height;
            this.fw = (float)width;
            this.fwh = this.fw / 2.0f;
            this.fh = (float)height;
            this.fhh = this.fh / 2.0f;
            this.a = a;
            this.mu = mu;

            // Reset buffers
            this.Reset(x1, y1);
        }

        public int Width
        {
            get { return this.width; }
        }

        public int Height
        {
            get { return this.height; }
        }

        public double A
        {
            get { return this.a; }
            set { this.a = value; }
        }

        public double Mu
        {
            get { return this.mu; }
            set { this.mu = value; }
        }

        public Texture2D ImageTexture
        {
            get { return this.imageTexture; }
        }

        public Vector2 Center
        {
            get { return this.center; }
            set { this.center = value; }
        }

        public float Scale
        {
            get { return this.scale; }
            set { this.scale = value; }
        }

        public UInt32 Iterations
        {
            get { return this.iterations; }
        }

        public void Reset()
        {
            this.Reset(this.oldX1, this.oldY1);
        }

        public void Reset(double x1, double y1)
        {
            // Cache and reset position
            this.oldX1 = x1;
            this.oldY1 = y1;
            this.x = x1;
            this.y = y1;

            // Reset iteration count
            this.iterations = 0;

            // Create buffer
            int imageSize = width * height;
            this.imageBuffer = new byte[imageSize];

            // Create texture
            this.imageTexture = new Texture2D(
                graphicsDevice,
                width,
                height,
                1,
                TextureUsage.None,
                SurfaceFormat.Luminance8);

            // Update the luminance data of the texture
            this.imageTexture.SetData(this.imageBuffer);
        }

        public void Iterate(int steps)
        {
            double mup = 2.0 * (1.0 - this.mu);
            for (int i = 0; i < steps; i++)
            {
                // Calculate 
                double xx = this.x * this.x;
                double fxn = this.mu * this.x + (mup * xx) / (1.0 + xx);
                double xnp1 = this.y + this.a * (1.0 - 0.05 * this.y * this.y) * this.y + fxn;
                double xnp1xnp1 = xnp1*xnp1;
                double fxnp1 = this.mu * xnp1 + (mup * xnp1xnp1) / (1.0 + xnp1xnp1);
                double ynp1 = -this.x + fxnp1;
                this.x = xnp1;
                this.y = ynp1;
                this.iterations++;

                // Draw
                this.PutPixel(xnp1, ynp1, 1);
            }

            // Re-reate texture
            this.imageTexture = new Texture2D(
                this.graphicsDevice,
                this.width,
                this.height,
                1,
                TextureUsage.None,
                SurfaceFormat.Luminance8); // Could be Palette8

            // Update the luminance data of the texture
            this.imageTexture.SetData(this.imageBuffer);
        }

        private void PutPixel(double x, double y, byte luminance)
        {
            // Map pixel to buffer coordinates
            float bx = (((float)x - this.center.X) * this.scale) * this.fw + this.fwh;
            float by = (((float)y - this.center.Y) * this.scale) * this.fw + this.fhh;
            if ((bx >= 0.0f) && (bx < this.fw) && (by >= 0.0f) && (by < this.fh))
            {
                int offset = (int)bx + this.width * (int)by;
                this.imageBuffer[offset] += luminance;
            }
        }
    }
}

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