package awa.imu;

import javax.media.j3d.*;
import javax.vecmath.*;

public class GyroRateIndicator extends Shape3D
{
    private Geometry voGeometry;
    private Appearance voAppearance;
    private Color3f triColor;
    
    // create Shape3D with geometry and appearance
    // the geometry is created in method createGeometry
    // the appearance is created in method createAppearance
    public GyroRateIndicator(Color3f color) {
        this.triColor = color;
        voGeometry = createGeometry(Math.PI);
        voAppearance = createAppearance();
        this.setGeometry(voGeometry);
        this.setAppearance(voAppearance);
        this.setCapability(Shape3D.ALLOW_GEOMETRY_WRITE);
    }
    
    public void showRate(double rate) {
        voGeometry = createGeometry(rate);
        this.setGeometry(voGeometry);
    }
    
    private Geometry createGeometry(double angleR) 
    {
        TriangleFanArray tfa;
        int N = 7;
        int totalN = 4*(N+1);
        Point3f coords[] = new Point3f[totalN];
        Color3f colors[] = new Color3f[totalN];
        int stripCounts[] = {N+1, N+1, N+1, N+1};
        
        float r = 1.2f;
        float w = 0.0f;
        int n;
        double a;
        float x, y;
        
        // set the central points for four triangle fan strips
        coords[0*(N+1)] = new Point3f(0.0f, 0.0f, w);
        coords[1*(N+1)] = new Point3f(0.0f, 0.0f, 0.0f);
        coords[2*(N+1)] = new Point3f(0.0f, 0.0f, 0.0f);
        coords[3*(N+1)] = new Point3f(0.0f, 0.0f, -w);
        
        for (a = 0,n = 0; n < N; a = angleR/(N-1) * ++n) {
            x = (float) (r * Math.cos(a));
            y = (float) (r * Math.sin(a));
            
            coords[0*(N+1)+N-n] = new Point3f(x, y, w);
            coords[1*(N+1)+n+1] = new Point3f(x, y, w);
            coords[2*(N+1)+N-n] = new Point3f(x, y, -w);
            coords[3*(N+1)+n+1] = new Point3f(x, y, -w);
        }
        
        for (int i=0; i < totalN; i++) {
            colors[i] = triColor;
        }
        
        tfa = new TriangleFanArray (totalN, GeometryArray.COORDINATES|GeometryArray.COLOR_3, stripCounts);
        
        tfa.setCoordinates(0, coords);
        tfa.setColors(0, colors);
        
        return tfa;    
    }
    
    Appearance createAppearance() 
    {
        Appearance app = new Appearance();
        //appX.setColoringAttributes(new ColoringAttributes(0.1f, 0.8f, 0.1f, ColoringAttributes.SHADE_GOURAUD));
        app.setMaterial(new Material(new Color3f(0.5f, 0.5f, 0.5f), new Color3f(0.5f, 0.5f, 0.5f), new Color3f(0.2f, 0.2f, 0.2f), new Color3f(0.0f, 0.0f, 0.0f), 72));
        app.setTransparencyAttributes(new TransparencyAttributes(TransparencyAttributes.BLENDED, 0.5f));

        return app;
    }
}