kinect-viewer / trackball.c

Cliff Biffle 788984a 




















































Cliff Biffle bce82f8 


Cliff Biffle 788984a 



Cliff Biffle bce82f8 
Cliff Biffle 788984a 




















Cliff Biffle bce82f8 

Cliff Biffle 788984a 
Cliff Biffle bce82f8 
Cliff Biffle 788984a 
Cliff Biffle bce82f8 
Cliff Biffle 788984a 
Cliff Biffle bce82f8 

Cliff Biffle 788984a 

Cliff Biffle bce82f8 

Cliff Biffle 788984a 


Cliff Biffle bce82f8 
Cliff Biffle 788984a 
Cliff Biffle bce82f8 
Cliff Biffle 788984a 









Cliff Biffle bce82f8 

Cliff Biffle 788984a 






Cliff Biffle bce82f8 
Cliff Biffle 788984a 
Cliff Biffle bce82f8 
Cliff Biffle 788984a 











Cliff Biffle bce82f8 



Cliff Biffle 788984a 


Cliff Biffle bce82f8 
Cliff Biffle 788984a 




Cliff Biffle bce82f8 
Cliff Biffle 788984a 













Cliff Biffle bce82f8 

Cliff Biffle 788984a 
Cliff Biffle bce82f8 
Cliff Biffle 788984a 













































//
// File:		trackball.c
//
// Abstract:	Implements a trackball like camera system
//
// Version:		1.1 - minor fixes.
//				1.0 - Original release.
//				
//
// Disclaimer:	IMPORTANT:  This Apple software is supplied to you by Apple Inc. ("Apple")
//				in consideration of your agreement to the following terms, and your use,
//				installation, modification or redistribution of this Apple software
//				constitutes acceptance of these terms.  If you do not agree with these
//				terms, please do not use, install, modify or redistribute this Apple
//				software.
//
//				In consideration of your agreement to abide by the following terms, and
//				subject to these terms, Apple grants you a personal, non - exclusive
//				license, under Apple's copyrights in this original Apple software ( the
//				"Apple Software" ), to use, reproduce, modify and redistribute the Apple
//				Software, with or without modifications, in source and / or binary forms;
//				provided that if you redistribute the Apple Software in its entirety and
//				without modifications, you must retain this notice and the following text
//				and disclaimers in all such redistributions of the Apple Software. Neither
//				the name, trademarks, service marks or logos of Apple Inc. may be used to
//				endorse or promote products derived from the Apple Software without specific
//				prior written permission from Apple.  Except as expressly stated in this
//				notice, no other rights or licenses, express or implied, are granted by
//				Apple herein, including but not limited to any patent rights that may be
//				infringed by your derivative works or by other works in which the Apple
//				Software may be incorporated.
//
//				The Apple Software is provided by Apple on an "AS IS" basis.  APPLE MAKES NO
//				WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED
//				WARRANTIES OF NON - INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A
//				PARTICULAR PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND OPERATION
//				ALONE OR IN COMBINATION WITH YOUR PRODUCTS.
//
//				IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL OR
//				CONSEQUENTIAL DAMAGES ( INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
//				SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
//				INTERRUPTION ) ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION, MODIFICATION
//				AND / OR DISTRIBUTION OF THE APPLE SOFTWARE, HOWEVER CAUSED AND WHETHER
//				UNDER THEORY OF CONTRACT, TORT ( INCLUDING NEGLIGENCE ), STRICT LIABILITY OR
//				OTHERWISE, EVEN IF APPLE HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// Copyright ( C ) 2000-2007 Apple Inc. All Rights Reserved.
//

#include "trackball.h"

#include <math.h>

static const float kTol = 0.001F;
static const float kRad2Deg = 180.F / 3.1415927F;
static const float kDeg2Rad = 3.1415927F / 180.F;

float gRadiusTrackball;
float gStartPtTrackball[3];
float gEndPtTrackball[3];
int gXCenterTrackball = 0, gYCenterTrackball = 0;

// mouse positon and view size as inputs
void startTrackball (long x, long y, long originX, long originY, long width, long height)
{
    float xxyy;
    float nx, ny;
    
    /* Start up the trackball.  The trackball works by pretending that a ball
       encloses the 3D view.  You roll this pretend ball with the mouse.  For
       example, if you click on the center of the ball and move the mouse straight
       to the right, you roll the ball around its Y-axis.  This produces a Y-axis
       rotation.  You can click on the "edge" of the ball and roll it around
       in a circle to get a Z-axis rotation.
       
       The math behind the trackball is simple: start with a vector from the first
       mouse-click on the ball to the center of the 3D view.  At the same time, set the radius
       of the ball to be the smaller dimension of the 3D view.  As you drag the mouse
       around in the 3D view, a second vector is computed from the surface of the ball
       to the center.  The axis of rotation is the cross product of these two vectors,
       and the angle of rotation is the angle between the two vectors.
     */
    nx = (float) width;
    ny = (float) height;
    if (nx > ny)
        gRadiusTrackball = ny * 0.5F;
    else
        gRadiusTrackball = nx * 0.5F;
    // Figure the center of the view.
    gXCenterTrackball = (int) (originX + width * 0.5);
    gYCenterTrackball = (int) (originY + height * 0.5);
    
    // Compute the starting vector from the surface of the ball to its center.
    gStartPtTrackball [0] = (float) x - gXCenterTrackball;
    gStartPtTrackball [1] = (float) y - gYCenterTrackball;
    xxyy = gStartPtTrackball [0] * gStartPtTrackball[0] + gStartPtTrackball [1] * gStartPtTrackball [1];
    if (xxyy > gRadiusTrackball * gRadiusTrackball) {
        // Outside the sphere.
        gStartPtTrackball[2] = 0.F;
    } else
        gStartPtTrackball[2] = sqrtf(gRadiusTrackball * gRadiusTrackball - xxyy);
    
}

// update to new mouse position, output rotation angle
void rollToTrackball (long x, long y, float rot [4]) // rot is output rotation angle
{
    float xxyy;
    float cosAng, sinAng;
    float ls, le, lr;
    
    gEndPtTrackball[0] = (float) x - gXCenterTrackball;
    gEndPtTrackball[1] = (float) y - gYCenterTrackball;
    if (fabs (gEndPtTrackball [0] - gStartPtTrackball [0]) < kTol && fabs (gEndPtTrackball [1] - gStartPtTrackball [1]) < kTol)
        return; // Not enough change in the vectors to have an action.

    // Compute the ending vector from the surface of the ball to its center.
    xxyy = gEndPtTrackball [0] * gEndPtTrackball [0] + gEndPtTrackball [1] * gEndPtTrackball [1];
    if (xxyy > gRadiusTrackball * gRadiusTrackball) {
        // Outside the sphere.
        gEndPtTrackball [2] = 0.F;
    } else
        gEndPtTrackball[ 2] = sqrtf (gRadiusTrackball * gRadiusTrackball - xxyy);
        
    // Take the cross product of the two vectors. r = s X e
    rot[1] =  gStartPtTrackball[1] * gEndPtTrackball[2] - gStartPtTrackball[2] * gEndPtTrackball[1];
    rot[2] = -gStartPtTrackball[0] * gEndPtTrackball[2] + gStartPtTrackball[2] * gEndPtTrackball[0];
    rot[3] =  gStartPtTrackball[0] * gEndPtTrackball[1] - gStartPtTrackball[1] * gEndPtTrackball[0];
    
    // Use atan for a better angle.  If you use only cos or sin, you only get
    // half the possible angles, and you can end up with rotations that flip around near
    // the poles.
    
    // cos(a) = (s . e) / (||s|| ||e||)
    cosAng = gStartPtTrackball[0] * gEndPtTrackball[0] + gStartPtTrackball[1] * gEndPtTrackball[1] + gStartPtTrackball[2] * gEndPtTrackball[2]; // (s . e)
    ls = sqrtf(gStartPtTrackball[0] * gStartPtTrackball[0] + gStartPtTrackball[1] * gStartPtTrackball[1] + gStartPtTrackball[2] * gStartPtTrackball[2]);
    ls = 1.F / ls; // 1 / ||s||
    le = sqrtf(gEndPtTrackball[0] * gEndPtTrackball[0] + gEndPtTrackball[1] * gEndPtTrackball[1] + gEndPtTrackball[2] * gEndPtTrackball[2]);
    le = 1.F / le; // 1 / ||e||
    cosAng = cosAng * ls * le;
    
    // sin(a) = ||(s X e)|| / (||s|| ||e||)
    sinAng = lr = sqrtf(rot[1] * rot[1] + rot[2] * rot[2] + rot[3] * rot[3]); // ||(s X e)||;
                                // keep this length in lr for normalizing the rotation vector later.
    sinAng = sinAng * ls * le;
    rot[0] = (float) atan2 (sinAng, cosAng) * kRad2Deg; // GL rotations are in degrees.
    
    // Normalize the rotation axis.
    lr = 1.F / lr;
    rot[1] *= lr; rot[2] *= lr; rot[3] *= lr;
    
    // returns rotate
}

static void rotation2Quat (float *A, float *q)
{
    float ang2;  // The half-angle
    float sinAng2; // sin(half-angle)
    
    // Convert a GL-style rotation to a quaternion.  The GL rotation looks like this:
    // {angle, x, y, z}, the corresponding quaternion looks like this:
    // {{v}, cos(angle/2)}, where {v} is {x, y, z} / sin(angle/2).
    
    ang2 = A[0] * kDeg2Rad * 0.5F;  // Convert from degrees ot radians, get the half-angle.
    sinAng2 = sinf(ang2);
    q[0] = A[1] * sinAng2; q[1] = A[2] * sinAng2; q[2] = A[3] * sinAng2;
    q[3] = cosf(ang2);
}

void addToRotationTrackball (float * dA, float * A)
{
    float q0[4], q1[4], q2[4];
	float theta2, sinTheta2;
    
    // Figure out A' = A . dA
    // In quaternions: let q0 <- A, and q1 <- dA.
    // Figure out q2 = q1 + q0 (note the order reversal!).
    // A' <- q3.
    
    rotation2Quat(A, q0);
    rotation2Quat(dA, q1);
    
    // q2 = q1 + q0;
    q2[0] = q1[1]*q0[2] - q1[2]*q0[1] + q1[3]*q0[0] + q1[0]*q0[3];
    q2[1] = q1[2]*q0[0] - q1[0]*q0[2] + q1[3]*q0[1] + q1[1]*q0[3];
    q2[2] = q1[0]*q0[1] - q1[1]*q0[0] + q1[3]*q0[2] + q1[2]*q0[3];
    q2[3] = q1[3]*q0[3] - q1[0]*q0[0] - q1[1]*q0[1] - q1[2]*q0[2];
    // Here's an excersize for the reader: it's a good idea to re-normalize your quaternions
    // every so often.  Experiment with different frequencies.
    
    // An identity rotation is expressed as rotation by 0 about any axis.
    // The "angle" term in a quaternion is really the cosine of the half-angle.
    // So, if the cosine of the half-angle is one (or, 1.0 within our tolerance),
    // then you have an identity rotation.
    if (fabs(fabs(q2[3] - 1.)) < 1.0e-7) {
        // Identity rotation.
        A[0] = 0.0f;
        A[1] = 1.0f;
        A[2] = A[3] = 0.0f;
        return;
    }
    
    // If you get here, then you have a non-identity rotation.  In non-identity rotations,
    // the cosine of the half-angle is non-0, which means the sine of the angle is also
    // non-0.  So we can safely divide by sin(theta2).
    
    // Turn the quaternion back into an {angle, {axis}} rotation.
    theta2 = (float) acos (q2[3]);
    sinTheta2 = (float)  (1.0 /  sin ((double) theta2));
    A[0] = theta2 * 2.0f * kRad2Deg;
    A[1] = q2[0] * sinTheta2;
    A[2] = q2[1] * sinTheta2;
    A[3] = q2[2] * sinTheta2;
}
Tip: Filter by directory path e.g. /media app.js to search for public/media/app.js.
Tip: Use camelCasing e.g. ProjME to search for ProjectModifiedEvent.java.
Tip: Filter by extension type e.g. /repo .js to search for all .js files in the /repo directory.
Tip: Separate your search with spaces e.g. /ssh pom.xml to search for src/ssh/pom.xml.
Tip: Use ↑ and ↓ arrow keys to navigate and return to view the file.
Tip: You can also navigate files with Ctrl+j (next) and Ctrl+k (previous) and view the file with Ctrl+o.
Tip: You can also navigate files with Alt+j (next) and Alt+k (previous) and view the file with Alt+o.