//
// s.h
//

#include <math.h>
#include <string.h>

#ifndef M_PI
#define M_PI 3.14159265358979323846264338327950288 
#endif

static void _norm_vec( float *v )
{
    double x = v[0];
    double y = v[1];
    double z = v[2];
    double d = sqrt( x*x + y*y + z*z );

    if ( d > 0.0 ) {
        v[0] = (float)( x / d );
        v[1] = (float)( y / d );
        v[2] = (float)( z / d );
    }
}

static void _outp_vec( float *ans, float *v1, float *v2 ) /* ans = v1 * v2 */
{
    ans[0] = ( v1[1] * v2[2] - v1[2] * v2[1] );
    ans[1] = ( v1[2] * v2[0] - v1[0] * v2[2] );
    ans[2] = ( v1[0] * v2[1] - v1[1] * v2[0] );
}

static void _store_array( int idx, float *v, float *n, float *t, float *b, float *st, float *c,
                        float *v_array, float *n_array, float *t_array, float *b_array, float *st_array, float *c_array, unsigned short *i_array )
{
    for ( unsigned int i = 0; i < 3; i++ ) {
        v_array[idx*3+i] = v[i];
        //v_array[idx*4+i] = v[i];
        n_array[idx*3+i] = n[i];
        t_array[idx*3+i] = t[i];
        b_array[idx*3+i] = b[i];
    }
    //v_array[idx*4+3] = 1.f;
    for ( unsigned int i = 0; i < 2; i++ )
        st_array[idx*2+i] = st[i];
    for ( unsigned int i = 0; i < 4; i++ )
        c_array[idx*4+i] = c[i];
    i_array[idx] = idx;
}

static void _tToVTBN( float *v, float *t, float *b, float *n, float *st, float r )
{
    float theta = ( float )M_PI * st[1];
    float phai = 2.f * ( float )M_PI * st[0];
    float y = - r * cos( theta );
    float z = r * sin( theta ) * cos( phai );
    float x = r * sin( theta ) * sin( phai );
    float dxdt = r * cos( theta ) * sin( phai );
    float dzdt = r * cos( theta ) * cos( phai );
    float dydt = r * sin( theta );
    float dxdp = cos( phai );
    float dzdp = - sin( phai );
    float dydp = 0.f;
    v[0] = x;
    v[1] = y;
    v[2] = z;
    t[0] = dxdp;
    t[1] = dydp;
    t[2] = dzdp;
    _norm_vec( t );
    b[0] = dxdt;
    b[1] = dydt;
    b[2] = dzdt;
    _norm_vec( b );
    _outp_vec( n, t, b );
    _norm_vec( n );
}

static void _tToVTBN2( float *v, float *t, float *b, float *n, float *st, float l )
{
    v[0] = l * ( st[0] - 0.5f );
    v[1] = l * ( st[1] - 0.5f );
    v[2] = 0.f;
    t[0] = 1.f;
    t[1] = 0.f;
    t[2] = 0.f;
    n[0] = 0.f;
    n[1] = 0.f;
    n[2] = 1.f;
    b[0] = 0.f;
    b[1] = 1.f;
    b[2] = 0.f;
}


//
// namespace util
//

//namespace util {

typedef struct vertex_attr {
    float x, y, z;
    float nx, ny, nz;
    float tx, ty, tz;
    float s, t;
    float r, g, b, a;
} vertex_attr_t;

class base
{
public:
    base()
    {
        m_vertex    = 0;
        m_normal    = 0;
        m_tangent    = 0;
        m_binormal    = 0;
        m_color        = 0;
        m_texture    = 0;
        m_index        = 0;
        m_vertex_attr = 0;
        m_triangle_count = 0;
        m_index_count = 0;
        m_vertex_attr_stride = sizeof( vertex_attr_t );
    }
    virtual ~base()
    {
        if ( m_vertex )
            delete [] m_vertex;
        if ( m_normal )
            delete [] m_normal;
        if ( m_tangent )
            delete [] m_tangent;
        if ( m_binormal )
            delete [] m_binormal;
        if ( m_color )
            delete [] m_color;
        if ( m_texture )
            delete [] m_texture;
        if ( m_index )
            delete [] m_index;
        if ( m_vertex_attr )
            delete [] m_vertex_attr;
    }
    
public:
    virtual float *get_vertex() { return m_vertex; }
    virtual float *get_normal() { return m_normal; }
    virtual float *get_tangent() { return m_tangent; }
    virtual float *get_binormal() { return m_binormal; }
    virtual float *get_color() { return m_color; }
    virtual float *get_texture() { return m_texture; }
    virtual    void *get_vertex_array() { return ( void* )m_vertex_attr; }
    virtual unsigned short *get_index() { return m_index; }
    virtual unsigned int get_triangle_count() { return m_triangle_count; }
    virtual unsigned int get_index_count() { return m_index_count; }
    virtual unsigned int get_vertex_attr_stride() { return m_vertex_attr_stride; }

protected:
    float    *m_vertex;
    float    *m_normal;
    float    *m_tangent;
    float    *m_binormal;
    float    *m_color;
    float    *m_texture;
    vertex_attr_t    *m_vertex_attr;
    unsigned short    *m_index;
    unsigned int    m_triangle_count;
    unsigned int    m_index_count; // = vertex count
    unsigned int    m_vertex_attr_stride;
};

class sphere : public base
{
public:
    sphere();
    sphere( unsigned int i, unsigned int j, float r );
    virtual ~sphere();
};

sphere::sphere()
{
    sphere( 10, 10, 1.f );
}

sphere::sphere( unsigned int ni, unsigned int nj, float r )
{
    float v[3], n[3], t[3], b[3], st[2], c[4];

    m_triangle_count = ni * nj * 2;
    m_index_count = m_triangle_count * 3;

    m_vertex  = new float [ m_index_count * 3 ];
    //m_vertex  = new float [ m_index_count * 4 ];
    m_normal = new float [ m_index_count * 3 ];
    m_tangent = new float [ m_index_count * 3 ];
    m_binormal = new float [ m_index_count * 3 ];
    m_color = new float [ m_index_count * 4 ];
    m_texture = new float [ m_index_count * 2 ];
    m_index = new unsigned short [ m_index_count ];
    m_vertex_attr = new vertex_attr_t [ m_index_count ];

    int idx = 0;
    for ( unsigned int i = 0; i < ni; i++ ) {
        for ( unsigned int j = 0; j < nj; j++ ) {

            if ( j != 0 ) {
                // 0-0
                st[0] = ( float )i / ( float )ni;
                st[1] = ( float )j / ( float )nj;
                _tToVTBN( v, t, b, n, st, r );
                c[0] = 1.f; c[1] = 0.f; c[2] = 0.f; c[3] = 1.f;
                _store_array( idx++, v, n, t, b, st, c, m_vertex, m_normal, m_tangent, m_binormal, m_texture, m_color, m_index );
                // 0-1
                st[0] = ( float )( i + 1 ) / ( float )ni;
                st[1] = ( float )j / ( float )nj;
                _tToVTBN( v, t, b, n, st, r );
                c[0] = 0.f; c[1] = 1.f; c[2] = 0.f; c[3] = 1.f;
                _store_array( idx++, v, n, t, b, st, c, m_vertex, m_normal, m_tangent, m_binormal, m_texture, m_color, m_index );
                // 0-2
                st[0] = ( float )( i + 1 ) / ( float )ni;
                st[1] = ( float )( j + 1 ) / ( float )nj;
                _tToVTBN( v, t, b, n, st, r );
                c[0] = 0.f; c[1] = 0.f; c[2] = 1.f; c[3] = 1.f;
                _store_array( idx++, v, n, t, b, st, c, m_vertex, m_normal, m_tangent, m_binormal, m_texture, m_color, m_index );
            }
            if ( j != nj-1 ) {
                // 1-0
                st[0] = ( float )i / ( float )ni;
                st[1] = ( float )j / ( float )nj;
                _tToVTBN( v, t, b, n, st, r );
                c[0] = 1.f; c[1] = 1.f; c[2] = 0.f; c[3] = 1.f;
                _store_array( idx++, v, n, t, b, st, c, m_vertex, m_normal, m_tangent, m_binormal, m_texture, m_color, m_index );
                // 1-1
                st[0] = ( float )( i + 1 ) / ( float )ni;
                st[1] = ( float )( j + 1 ) / ( float )nj;
                _tToVTBN( v, t, b, n, st, r );
                c[0] = 1.f; c[1] = 0.f; c[2] = 1.f; c[3] = 1.f;
                _store_array( idx++, v, n, t, b, st, c, m_vertex, m_normal, m_tangent, m_binormal, m_texture, m_color, m_index );
                // 1-2
                st[0] = ( float )i / ( float )ni;
                st[1] = ( float )( j + 1 ) / ( float )nj;
                _tToVTBN( v, t, b, n, st, r );
                c[0] = 0.f; c[1] = 1.f; c[2] = 1.f; c[3] = 1.f;
                _store_array( idx++, v, n, t, b, st, c, m_vertex, m_normal, m_tangent, m_binormal, m_texture, m_color, m_index );
            }
        }
    }

    m_index_count = idx;

    for ( unsigned int i = 0; i < m_index_count; i++ ) {
        memcpy( &m_vertex_attr[i].x,    &m_vertex[ i*3 ],    sizeof( float )*3 );
        memcpy( &m_vertex_attr[i].nx,    &m_normal[ i*3 ],    sizeof( float )*3 );
        memcpy( &m_vertex_attr[i].tx,    &m_tangent[ i*3 ],    sizeof( float )*3 );
        memcpy( &m_vertex_attr[i].s,    &m_texture[ i*2 ],    sizeof( float )*2 );
        memcpy( &m_vertex_attr[i].r,    &m_color[ i*4 ],    sizeof( float )*4 );
    }
}

sphere::~sphere()
{
}

class squre : public base
{
public:
    squre();
    squre( unsigned int i, unsigned int j, float l );
    virtual ~squre();
};

squre::squre()
{
    squre( 10, 10, 1.f );
}

squre::squre( unsigned int ni, unsigned int nj, float l )
{
    float v[3], n[3], t[3], b[3], st[2], c[4];

    m_triangle_count = ni * nj * 2;
    m_index_count = m_triangle_count * 3;

    m_vertex  = new float [ m_index_count * 3 ];
    m_normal = new float [ m_index_count * 3 ];
    m_tangent = new float [ m_index_count * 3 ];
    m_binormal = new float [ m_index_count * 3 ];
    m_color = new float [ m_index_count * 4 ];
    m_texture = new float [ m_index_count * 2 ];
    m_index = new unsigned short [ m_index_count ];

    int idx = 0;
    for ( unsigned int i = 0; i < ni; i++ ) {
        for ( unsigned int j = 0; j < nj; j++ ) {

            // 0-0
            st[0] = ( float )i / ( float )ni;
            st[1] = ( float )j / ( float )nj;
            _tToVTBN2( v, t, b, n, st, l );
            c[0] = 1.f; c[1] = 0.f; c[2] = 0.f; c[3] = 1.f;
            _store_array( idx++, v, n, t, b, st, c, m_vertex, m_normal, m_tangent, m_binormal, m_texture, m_color, m_index );
            // 0-1
            st[0] = ( float )( i + 1 ) / ( float )ni;
            st[1] = ( float )j / ( float )nj;
            _tToVTBN2( v, t, b, n, st, l );
            c[0] = 0.f; c[1] = 1.f; c[2] = 0.f; c[3] = 1.f;
            _store_array( idx++, v, n, t, b, st, c, m_vertex, m_normal, m_tangent, m_binormal, m_texture, m_color, m_index );
            // 0-2
            st[0] = ( float )( i + 1 ) / ( float )ni;
            st[1] = ( float )( j + 1 ) / ( float )nj;
            _tToVTBN2( v, t, b, n, st, l );
            c[0] = 0.f; c[1] = 0.f; c[2] = 1.f; c[3] = 1.f;
            _store_array( idx++, v, n, t, b, st, c, m_vertex, m_normal, m_tangent, m_binormal, m_texture, m_color, m_index );
            // 1-0
            st[0] = ( float )i / ( float )ni;
            st[1] = ( float )j / ( float )nj;
            _tToVTBN2( v, t, b, n, st, l );
            c[0] = 1.f; c[1] = 1.f; c[2] = 0.f; c[3] = 1.f;
            _store_array( idx++, v, n, t, b, st, c, m_vertex, m_normal, m_tangent, m_binormal, m_texture, m_color, m_index );
            // 1-1
            st[0] = ( float )( i + 1 ) / ( float )ni;
            st[1] = ( float )( j + 1 ) / ( float )nj;
            _tToVTBN2( v, t, b, n, st, l );
            c[0] = 1.f; c[1] = 0.f; c[2] = 1.f; c[3] = 1.f;
            _store_array( idx++, v, n, t, b, st, c, m_vertex, m_normal, m_tangent, m_binormal, m_texture, m_color, m_index );
            // 1-2
            st[0] = ( float )i / ( float )ni;
            st[1] = ( float )( j + 1 ) / ( float )nj;
            _tToVTBN2( v, t, b, n, st, l );
            c[0] = 0.f; c[1] = 1.f; c[2] = 1.f; c[3] = 1.f;
            _store_array( idx++, v, n, t, b, st, c, m_vertex, m_normal, m_tangent, m_binormal, m_texture, m_color, m_index );
        }
    }

    m_index_count = idx;
}

squre::~squre()
{
}

//} // end namespace