Please advice!
Trying to rotate PVector "ab" by an angle "ang" to a point c to form an inner triangle to the outer triangle "pqr". After rotation the two triangular planes are not in the same plane as seen in the difference of their normals. Is the rotation not happenning correctly.
PVector a ;
PVector b ;
PVector c = new PVector(0, 0, 0) ;
PVector bP, n1 ;
float nn;
PVector p = new PVector( random(0, 300), random(0, 300), random(0, 300) );
PVector q = new PVector( random(0, 300), random(0, 300), random(0, 300) ) ;
PVector r = new PVector( random(0, 300), random(0, 300), random(0, 300) ) ;
PVector n ;
PVector g ;
PVector temp_n ;
float ang = 0.8 ;
float l_ab, l_bc, l_ac;
float d = 0 ;
boolean map = false;
void setup()
{
size( 700, 700, P3D);
g = new PVector( (p.x+q.x+r.x)/3, (p.y+q.y+r.y)/3, (p.z+q.z+r.z)/3 ) ;
l_ac = PVector.dist( p, r );
l_bc = PVector.dist( q, r ) ;
l_ab = PVector.dist( p, q ) ;
PVector temp_a = PVector.sub( g, p );
temp_a.normalize();
temp_a.mult(d) ;
temp_a.add(p);
a = temp_a.get(); // pvector "a" from origin
PVector temp_b = PVector.sub( q, p ) ;
temp_b.normalize();
temp_b.mult(l_ab) ;
temp_b.add( a ) ;
b = temp_b.get() ; // pvector "b" from origin
PVector nTemp= PVector.sub(q, a).cross(PVector.sub(r, a));
nTemp.normalize() ;
n = nTemp.get(); // normal to the triangular plane
c.x= (a.x*((n.y*n.y)+(n.z*n.z)) - (n.x*((a.y*n.y)+(a.z*n.z)-(n.x*b.x)-(n.y*b.y)-(n.z*b.z))))*(1-cos(ang)) + (b.x*cos(ang)) + ((-(a.z*n.y)+(a.y*n.z)-(n.z*b.y)+(n.y*b.z))*sin(ang)) ;
c.y= (a.y*((n.x*n.x)+(n.z*n.z)) - (n.y*((a.x*n.x)+(a.z*n.z)-(n.x*b.x)-(n.y*b.y)-(n.z*b.z))))*(1-cos(ang)) + (b.y*cos(ang)) + (( (a.z*n.x)-(a.x*n.z)+(n.z*b.x)-(n.x*b.z))*sin(ang)) ;
c.z= (a.z*((n.x*n.x)+(n.y*n.y)) - (n.z*((a.x*n.x)+(a.y*n.z)-(n.x*b.x)-(n.y*b.y)-(n.z*b.z))))*(1-cos(ang)) + (b.z*cos(ang)) + ((-(a.y*n.x)+(a.x*n.y)-(n.y*b.x)+(n.x*b.y))*sin(ang)) ;
temp_n = n ;
temp_n.mult(30); // for the normal to be seen
temp_n.add(p); // to draw the normal line
}
void draw()
{
background( 204 ) ;
navigate();
firstTriangle();
if ( map) // presss any key
{
mappedTriangle();
}
}
void firstTriangle()
{
stroke( 255, 0, 0 );
line( p.x, p.y, p.z, q.x, q.y, q.z ) ;
line( q.x, q.y, q.z, r.x, r.y, r.z );
line( r.x, r.y, r.z, p.x, p.y, p.z );
stroke( 120 );
line( p.x, p.y, p.z, temp_n.x, temp_n.y, temp_n.z );
strokeWeight(1);
point( g.x, g.y, g.z );
}
void mappedTriangle()
{
stroke( 0, 0, 255 );
line( a.x, a.y, a.z, b.x, b.y, b.z );
line( b.x, b.y, b.z, c.x, c.y, c.z );
line( a.x, a.y, a.z, c.x, c.y, c.z );
strokeWeight( 1 );
point(c.x, c.y, c.z);
strokeWeight(1);
PVector nTemp1= PVector.sub(b, a).cross(PVector.sub(c, a));
nTemp1.normalize() ;
n1 = nTemp1.get();
n1.mult(30);
// the new normal (this should be the same as old if the rotation was correct
n1.add(p);
stroke( 20 );
line( p.x, p.y, p.z, n1.x, n1.y, n1.z ); // showing the new normal
nn = PVector.angleBetween( n, n1 ); // angle between the normals for the two triangles
println( nn );
}
void keyPressed()
{
if ( !map)
{
map=true;
}
else
{
map=false;
}
}
