import go.*;

public class GoTorus
{
    double             radius;
    int                slices;
    double             ringRadius;
    int                ringSlices;
    GoTriangleStrip[]  dataSolid;
    GoLineLoop[]       dataWire;
    boolean            solidDirty;
    boolean            wireDirty;

    public GoTorus(double radius,
                   int  slices,
                   double ringRadius,
                   int  ringSlices)
    {
        this.radius = radius;
        this.slices = slices;
        this.ringRadius = ringRadius;
        this.ringSlices = ringSlices;
        
        solidDirty = true;
        wireDirty = true;
    }

    void renderSolid(Go go)
    {
        int i;
        
        if(solidDirty)
            updateSolid();
        
        go.push(Go.FLAGS);
        go.enable(Go.CULL);
        
        for(i = 0; i < ringSlices; i++) {
            go.render(dataSolid[i]);
        }
        
        go.pop(Go.FLAGS);
    }

    void renderWire(Go go)
    {
        int i;
        
        if(wireDirty)
            updateWire();
        
        for(i = 0; i < ringSlices + slices + 1; i++) {
            go.render(dataWire[i]);
        }
    }

    void renderWireSlices(Go go)
    {
        int i;
        
        if(wireDirty)
            updateWire();
        
        for(i = ringSlices; i < ringSlices + slices + 1; i++) {
            go.render(dataWire[i]);
        }
    }

    
    void updateSolid()
    {
        int     i, j;

        //
        // Create the data.
        //
    
        double[][][] d = new double[slices + 1][ringSlices + 1][3];
        double[][][] c = new double[slices + 1][ringSlices + 1][3];

        double ringSliceAngleInc = 2.0 * Math.PI / ringSlices;
        double ringSliceAngle = 0.0;

        for(i = 0; i <= ringSlices; i++) {

            d[0][i][0] = radius + ringRadius * Math.cos(ringSliceAngle);;
            d[0][i][1] = 0;
            d[0][i][2] = ringRadius * Math.sin(ringSliceAngle);

            c[0][i][0] = radius;
            c[0][i][1] = 0;
            c[0][i][2] = 0;

            ringSliceAngle += ringSliceAngleInc;
        }

        double sliceAngleInc = 2.0 * Math.PI / slices;
        double sliceAngle = sliceAngleInc;

        for(i = 1; i <= slices; i++) {

            for(j = 0; j <= ringSlices; j++) {

                d[i][j][0] = d[0][j][0] * Math.cos(sliceAngle);
                d[i][j][1] = d[0][j][0] * Math.sin(sliceAngle);
                d[i][j][2] = d[0][j][2];

                c[i][j][0] = c[0][j][0] * Math.cos(sliceAngle);
                c[i][j][1] = c[0][j][0] * Math.sin(sliceAngle);
                c[i][j][2] = c[0][j][2];
            }

            sliceAngle += sliceAngleInc;
        }

        //
        // Create the triangle strips.
        //

        dataSolid = new GoTriangleStrip[ringSlices];

        for(i = 0; i < ringSlices; i++) {

            dataSolid[i] = new GoTriangleStrip((slices + 1) * 2, Go.NORMAL);

            for(j = 0; j <= slices; j++) {
            
                dataSolid[i].xyz(j*2, d[j][i+1][0], d[j][i+1][1], d[j][i+1][2]);
                dataSolid[i].xyz(j*2+1, d[j][i][0], d[j][i][1], d[j][i][2]);

                dataSolid[i].ijk(j*2,
                                 d[j][i+1][0] - c[j][i+1][0],
                                 d[j][i+1][1] - c[j][i+1][1],
                                 d[j][i+1][2] - c[j][i+1][2]);
                dataSolid[i].ijk(j*2+1,
                                 d[j][i][0] - c[j][i][0],
                                 d[j][i][1] - c[j][i][1],
                                 d[j][i][2] - c[j][i][2]);
            }
        }
    
        solidDirty = false;
    }

    void updateWire()
    {
        int     i, j;

        //
        // Create the data.
        //
    
        double[][][] d = new double[slices + 1][ringSlices + 1][3];

        double ringSliceAngleInc = 2.0 * Math.PI / ringSlices;
        double ringSliceAngle = 0.0;

        for(i = 0; i <= ringSlices; i++) {

            d[0][i][0] = radius + ringRadius * Math.cos(ringSliceAngle);;
            d[0][i][1] = 0;
            d[0][i][2] = ringRadius * Math.sin(ringSliceAngle);

            ringSliceAngle += ringSliceAngleInc;
        }

        double sliceAngleInc = 2.0 * Math.PI / slices;
        double sliceAngle = sliceAngleInc;

        for(i = 1; i <= slices; i++) {

            for(j = 0; j <= ringSlices; j++) {

                d[i][j][0] = d[0][j][0] * Math.cos(sliceAngle);
                d[i][j][1] = d[0][j][0] * Math.sin(sliceAngle);
                d[i][j][2] = d[0][j][2];
            }

            sliceAngle += sliceAngleInc;
        }

        //
        // Create the line loops.
        //

        dataWire = new GoLineLoop[ringSlices + slices + 1];

        int count = 0;

        for(i = 0; i < ringSlices; i++) {

            dataWire[count] = new GoLineLoop(slices);

            for(j = 0; j < slices; j++) {
            
                dataWire[count].xyz(j, d[j][i][0], d[j][i][1], d[j][i][2]);
            }

            count++;
        }

        for(j = 0; j <= slices; j++) {
        
            dataWire[count] = new GoLineLoop(ringSlices);

            for(i = 0; i < ringSlices; i++) {

                dataWire[count].xyz(i, d[j][i][0], d[j][i][1], d[j][i][2]);
            }

            count++;
        }
        
        wireDirty = false;
    }
}