void drawStroke3(void){
float Amp=20;
float Freq=40;
glLineWidth(1);
glBegin(GL_LINE_STRIP);
float strokeWidth=20;
//glBegin(GL_TRIANGLE_STRIP);
for( int i=0; i<numPoint-1; i++){
Vec2d currentPoint= pointList[i];
//glVertex2f(pointList[i].x, pointList[i].y);
Vec2d A= pointList[i-1];
Vec2d B = pointList[i+1];
Vec2d V= B-A;
V.normalize();
Vec2d Vp;
Vp.x = V.y * -1.0;
Vp.y= V.x;
Vec2d C= currentPoint + Vp*(Amp*sin_deg(i*Freq));
glVertex2f(C.x, C.y);
}
glEnd();
}
