//----------------------------------------------------------
//Pinch controll
//----------------------------------------------------------
void TapCamera::BeginPinch( const Vec2& v1, const Vec2& v2 )
{
if( dragging_ )
EndDrag();
if( pinching_ )
EndPinch();
BeginDrag( Vec2() );
vec_pinch_start_center_ = (v1 + v2) / 2.f;
Vec2 vec = v1 - v2;
float x_diff;
float y_diff;
vec.Value( x_diff, y_diff );
pinch_start_distance_SQ_ = x_diff * x_diff + y_diff * y_diff;
camera_rotation_start_ = atan2f( y_diff, x_diff );
camera_rotation_now_ = 0;
pinching_ = true;
momentum_ = false;
//Init momentum factors
vec_offset_delta_ = Vec3();
}
void TapCamera::Pinch( const Vec2& v1, const Vec2& v2 )
{
if( !pinching_ )
return;
//Update momentum factor
vec_offset_last_ = vec_offset_now_;
float x_diff, y_diff;
Vec2 vec = v1 - v2;
vec.Value( x_diff, y_diff );
float fDistanceSQ = x_diff * x_diff + y_diff * y_diff;
float f = pinch_start_distance_SQ_ / fDistanceSQ;
if( f < 1.f )
f = -1.f / f + 1.0f;
else
f = f - 1.f;
if( isnan( f ) )
f = 0.f;
vec = (v1 + v2) / 2.f - vec_pinch_start_center_;
vec_offset_now_ = Vec3( vec, flip_z_ * f );
//Update momentum factor
vec_offset_delta_ = vec_offset_delta_ * MOMENTUM_FACTOR
+ (vec_offset_now_ - vec_offset_last_);
//
//Update ration quaternion
float fRotation = atan2f( y_diff, x_diff );
camera_rotation_now_ = fRotation - camera_rotation_start_;
//Trackball rotation
quat_ball_rot_ = Quaternion( 0.f, 0.f, sinf( -camera_rotation_now_ * 0.5f ),
cosf( -camera_rotation_now_ * 0.5f ) );
}