toxi::geom::Matrix4x4 toxi::geom::Matrix4x4::lookAt( Vec3D & eye, Vec3D & target, Vec3D & up )
{
Vec3D f = eye.sub( target ).normalize();
Vec3D s = up.cross( f ).normalize();
Vec3D t = f.cross( s ).normalize();
return set( s.getX(), s.getY(), s.getZ(), -s.dot( eye ), t.getX(), t.getY(), t.getZ(), -t.dot( eye ), f.getX(),
f.getY(), f.getZ(), -f.dot( eye ), 0, 0, 0, 1 );
}
// using vector to a point, unit normal vector to a plane, and a vector
// to a point in the plane, find distance from point to plane
static double distancePointToPlane(const Vec3D& point,
const Vec3D& unitN,
const Vec3D& pointInPlane)
{
Vec3D diff = point - pointInPlane;
return unitN.dot(diff);
}
toxi::geom::Vec3D toxi::geom::Triangle3D::toBarycentric( Vec3D & p )
{
Vec3D e = b.sub( a ).cross( c.sub( a ) );
Vec3D n = e.getNormalized();
// Compute twice area of triangle ABC
float areaABC = n.dot( e );
// Compute lambda1
float areaPBC = n.dot( b.sub( p ).cross( c.sub( p ) ) );
float l1 = areaPBC / areaABC;
// Compute lambda2
float areaPCA = n.dot( c.sub( p ).cross( a.sub( p ) ) );
float l2 = areaPCA / areaABC;
// Compute lambda3
float l3 = 1.0f - l1 - l2;
return Vec3D(l1, l2, l3);
}
bool toxi::geom::AABB::planeBoxOverlap( Vec3D & normal, const float & d, const Vec3D & maxBox )
{
Vec3D vmin = Vec3D();
Vec3D vmax = Vec3D();
if (normal.getX() > 0.0f) {
vmin.setX( -maxBox.getX() );
vmax.setX( maxBox.getX() );
} else {
vmin.setX( maxBox.getX() );
vmax.setX( -maxBox.getX() );
}
if (normal.getY() > 0.0f) {
vmin.setY( -maxBox.getY() );
vmax.setY( maxBox.getY() );
} else {
vmin.setY( maxBox.getY() );
vmax.setY( -maxBox.getY() );
}
if (normal.getZ() > 0.0f) {
vmin.setZ( -maxBox.getZ() );
vmax.setZ( maxBox.getZ() );
} else {
vmin.setZ( maxBox.getZ() );
vmax.setZ( -maxBox.getZ() );
}
if (normal.dot(vmin) + d > 0.0f) {
return false;
}
if (normal.dot(vmax) + d >= 0.0f) {
return true;
}
return false;
}
int TriangleMeshData::createDebugMesh( CFly::Object* obj , CFly::Material* mat )
{
struct vtx_t
{
vtx_t( Vec3D const& v , Vec3D const& c)
:vtx(v),color(c){}
Vec3D vtx;
Vec3D color;
};
std::vector< vtx_t > vtxVec;
std::vector< TriangleIndex > triVec;
vtxVec.reserve( m_triVec.size() * 3 );
triVec.reserve( m_triVec.size() );
int index = -1;
for (int i = 0; i < m_triVec.size(); ++i )
{
TriangleIndex& tri = m_triVec[i];
Vec3D& v0 = m_vertexVec[ tri.v[0] ];
Vec3D& v1 = m_vertexVec[ tri.v[1] ];
Vec3D& v2 = m_vertexVec[ tri.v[2] ];
Vec3D normal = ( v1 - v0 ).cross( v2 - v1 );
float len = sqrt( normal.dot(normal) );
float c = ( 2 + (normal.y + normal.z)/len )/ 4 ;
Vec3D color( c ,c , c );
vtxVec.push_back( vtx_t( v0 , color ) );
vtxVec.push_back( vtx_t( v1 , color ) );
vtxVec.push_back( vtx_t( v2 , color ) );
TriangleIndex t;
t.v[0] = ++index;
t.v[1] = ++index;
t.v[2] = ++index;
triVec.push_back( t );
}
return obj->createIndexedTriangle(
mat , CFVT_XYZ_CF1 ,
(float*) &vtxVec[0] , vtxVec.size() ,
&( triVec[0].v[0] ) , triVec.size() );
}
static double vecLength(Vec3D vec)
{
return std::sqrt(vec.dot(vec));
}
toxi::geom::Vec3D toxi::geom::Triangle3D::closestPointOnSurface( Vec3D & p )
{
Vec3D ab = b.sub( a );
Vec3D ac = c.sub( a );
Vec3D bc = c.sub( b );
Vec3D pa = p.sub( a );
Vec3D pb = p.sub( b );
Vec3D pc = p.sub( c );
Vec3D ap = a.sub( p );
Vec3D bp = b.sub( p );
Vec3D cp = c.sub( p );
// Compute parametric position s for projection P' of P on AB,
// P' = A + s*AB, s = snom/(snom+sdenom)
float snom = pa.dot( ab );
// Compute parametric position t for projection P' of P on AC,
// P' = A + t*AC, s = tnom/(tnom+tdenom)
float tnom = pa.dot( ac );
if ( snom <= 0.0f && tnom <= 0.0f ) {
return a; // Vertex region early out
}
float sdenom = pb.dot( a.sub( b ) );
float tdenom = pc.dot( a.sub( c ) );
// Compute parametric position u for projection P' of P on BC,
// P' = B + u*BC, u = unom/(unom+udenom)
float unom = pb.dot( bc );
float udenom = pc.dot( b.sub( c ) );
if ( sdenom <= 0.0f && unom <= 0.0f ) {
return b; // Vertex region early out
}
if ( tdenom <= 0.0f && udenom <= 0.0f ) {
return c; // Vertex region early out
}
// P is outside (or on) AB if the triple scalar product [N PA PB] <= 0
Vec3D n = ab.cross( ac );
float vc = n.dot( ap.crossSelf( bp ) );
// If P outside AB and within feature region of AB,
// return projection of P onto AB
if ( vc <= 0.0f && snom >= 0.0f && sdenom >= 0.0f ) {
// return a + snom / (snom + sdenom) * ab;
return a.add( ab.scaleSelf( snom / ( snom + sdenom ) ) );
}
// P is outside (or on) BC if the triple scalar product [N PB PC] <= 0
float va = n.dot( bp.crossSelf( cp ) );
// If P outside BC and within feature region of BC,
// return projection of P onto BC
if ( va <= 0.0f && unom >= 0.0f && udenom >= 0.0f ) {
// return b + unom / (unom + udenom) * bc;
return b.add( bc.scaleSelf( unom / ( unom + udenom ) ) );
}
// P is outside (or on) CA if the triple scalar product [N PC PA] <= 0
float vb = n.dot( cp.crossSelf( ap ) );
// If P outside CA and within feature region of CA,
// return projection of P onto CA
if ( vb <= 0.0f && tnom >= 0.0f && tdenom >= 0.0f ) {
// return a + tnom / (tnom + tdenom) * ac;
return a.add( ac.scaleSelf( tnom / ( tnom + tdenom ) ) );
}
// P must project inside face region. Compute Q using barycentric
// coordinates
float u = va / ( va + vb + vc );
float v = vb / ( va + vb + vc );
float w = 1.0f - u - v; // = vc / (va + vb + vc)
// return u * a + v * b + w * c;
return a.scale( u ).addSelf( b.scale( v ) ).addSelf( c.scale( w ) );
}
