Sphere.cpp

Go to the documentation of this file.

#include "Sphere.h"

Sphere::Sphere(float cx, float cy, float cz, float r, int p) {
        m_pSphereVertices = NULL;
        m_nNumSphereVertices = 0;

        createSphereGeometry(cx, cy, cz, r, p);

        if (m_pSphereVertices != NULL) {

                addFormat(ATT_VERTEX, ATT_FLOAT, 3, sizeof(float)*5);
                addFormat(ATT_NORMAL, ATT_FLOAT, 3, sizeof(float)*2);
                addFormat(ATT_TEX, ATT_FLOAT, 2, 0);
                setPrimitive(PRIM_QUAD_STRIP);
                setVertices(m_pSphereVertices, m_nNumSphereVertices, sizeof(Vertex));

                //delete [] m_pSphereVertices;
                //m_pSphereVertices = NULL;
                //m_nNumSphereVertices = 0;

                LOG_SUCCESS(("Object sphere loaded"));
        }
        else
                LOG_ERROR(("Unable to load object Sphere"));
}

Sphere::~Sphere() {
        m_pSphereVertices = NULL;               // deletion handled by Object.cpp
}

void Sphere::setVertData(int index, float tu, float tv, 
                                                float nx, float ny, float nz, 
                                                float vx, float vy, float vz)
{
        (m_pSphereVertices+index)->tu = tu;
        (m_pSphereVertices+index)->tv = tv;
        (m_pSphereVertices+index)->nx = nx;
        (m_pSphereVertices+index)->ny = ny;
        (m_pSphereVertices+index)->nz = nz;
        (m_pSphereVertices+index)->vx = vx;
        (m_pSphereVertices+index)->vy = vy;
        (m_pSphereVertices+index)->vz = vz;
}

void Sphere::createSphereGeometry(float cx, float cy, float cz, float r, int p)
{
    const float PI = 3.14159265358979f;
    const float TWOPI = 6.28318530717958f;
    const float PIDIV2 = 1.57079632679489f;

    float theta1 = 0.0;
    float theta2 = 0.0;
    float theta3 = 0.0;

    float ex = 0.0f;
    float ey = 0.0f;
    float ez = 0.0f;

    float px = 0.0f;
    float py = 0.0f;
    float pz = 0.0f;

    float tu  = 0.0f;
    float tv  = 0.0f;

    //-------------------------------------------------------------------------
    // If sphere precision is set to 4, then 20 verts will be needed to 
    // hold the array of GL_TRIANGLE_STRIP(s) and so on...
    //
    // Example:
    //
    // total_verts = (p/2) * ((p+1)*2)
    // total_verts = (4/2) * (  5  *2)
    // total_verts =   2   *  10
    // total_verts =      20
    //-------------------------------------------------------------------------

    m_nNumSphereVertices = (p/2) * ((p+1)*2);

    if( m_pSphereVertices != NULL )
    {
        delete []m_pSphereVertices;
        m_pSphereVertices = NULL;
        m_pSphereVertices = new Vertex[m_nNumSphereVertices];
    }
    else
    {
        m_pSphereVertices = new Vertex[m_nNumSphereVertices];
    }

    // Disallow a negative number for radius.
    if( r < 0 )
        r = -r;

    // Disallow a negative number for precision.
    if( p < 4 ) 
        p = 4;

    int k = -1;

    for( int i = 0; i < p/2; ++i )
    {
        theta1 = i * TWOPI / p - PIDIV2;
        theta2 = (i + 1) * TWOPI / p - PIDIV2;

        for( int j = 0; j <= p; ++j )
        {
            theta3 = j * TWOPI / p;

            ex = cosf(theta2) * cosf(theta3);
            ey = sinf(theta2);
            ez = cosf(theta2) * sinf(theta3);
            px = cx + r * ex;
            py = cy + r * ey;
            pz = cz + r * ez;
            tu  = -(j/(float)p);
            tv  = 2*(i+1)/(float)p;

            ++k;
            setVertData( k, tu, tv, ex, ey, ez, px, py, pz );

            ex = cosf(theta1) * cosf(theta3);
            ey = sinf(theta1);
            ez = cosf(theta1) * sinf(theta3);
            px = cx + r * ex;
            py = cy + r * ey;
            pz = cz + r * ez;
            tu  = -(j/(float)p);
            tv  = 2*i/(float)p;

            ++k;
            setVertData( k, tu, tv, ex, ey, ez, px, py, pz );
        }
    }
}

---