Sphere::Sphere( bool fullSphere, byte numSubDiv, float dim )
{
setPrimitiveType( PrimitiveType::Triangles );
VertexData position;
buildGeometry( fullSphere, numSubDiv, position, dim );
// Build Texture Coordinates.
BoundingBox box;
for( size_t i = 0; i < position.size(); i++ )
{
const Vector3& v = position[i];
box.add(v);
}
Vector3 center = box.getCenter();
std::vector<Vector3> texCoords;
for( size_t i = 0; i < position.size(); i++ )
{
const Vector3& vert = position[i];
Vector3 d = vert-center;
d.normalize();
// Conveert to spherical coordinates.
//float t = d.z / sqrt(d.x*d.x+d.y*d.y+d.z*d.z);
//float delta = acos(t);
//float phi = atan2(d.y, d.x);
//float u = delta / Math::PI;
//float v = phi / 2*Math::PI;
float u = std::asin(d.x) / PI + 0.5f;
float v = std::asin(d.y) / PI + 0.5f;
texCoords.push_back( Vector2(u, v) );
}
gb->set( VertexAttribute::Position, position );
gb->set( VertexAttribute::TexCoord0, texCoords );
}
void Sphere::buildGeometry( bool fullSphere, byte numSubDiv,
VertexData& pos, float dim)
{
GeometryBufferPtr gb = AllocateThis(GeometryBuffer);
setGeometryBuffer(gb);
// Rotate the vertices, else the sphere is not properly aligned.
Matrix4x3 rot = Matrix4x3::createRotation( EulerAngles(-60, 0, 0) );
for( size_t i = 0; i < ARRAY_SIZE(IcoDomeIndices); i++ )
{
const byte* p = IcoDomeIndices[i];
Vector3 v1( IcoVertices[p[0]][0], IcoVertices[p[0]][2], IcoVertices[p[0]][1] );
Vector3 v2( IcoVertices[p[1]][0], IcoVertices[p[1]][2], IcoVertices[p[1]][1] );
Vector3 v3( IcoVertices[p[2]][0], IcoVertices[p[2]][2], IcoVertices[p[2]][1] );
subdivide( rot*v1, rot*v2, rot*v3, numSubDiv, pos );
}
// If we don't want a full sphere, we return here.
if( fullSphere )
{
// These indices are the bottom of the sphere.
for( size_t i = 0; i < ARRAY_SIZE(IcoSphereIndices); i++ )
{
const byte* p = IcoSphereIndices[i];
Vector3 v1( IcoVertices[p[0]][0], IcoVertices[p[0]][2], IcoVertices[p[0]][1] );
Vector3 v2( IcoVertices[p[1]][0], IcoVertices[p[1]][2], IcoVertices[p[1]][1] );
Vector3 v3( IcoVertices[p[2]][0], IcoVertices[p[2]][2], IcoVertices[p[2]][1] );
subdivide( rot*v1, rot*v2, rot*v3, numSubDiv, pos );
}
}
// Scale all the vertices.
for( size_t i = 0; i < pos.size(); i++ )
{
Vector3& vec = pos[i];
vec *= dim;
}
}