Otherware/Otherware_1_SB_Development.iso/mac/hypercar/mactool/thinkcgu.sit/picture ƒ/trans.c

C/C++ Source or Header | 1991-02-26 | 4.4 KB | 191 lines

/*
*    FILE:        trans.c
*    AUTHOR:        R. Gonzalez
*    CREATED:    October 3, 1990
*
*    methods for Transformation class and descendants.  Use to
*    transform 3D coordinates.
*/

# include    "trans.h"
# include    <math.h>

/******************************************************************
*    initialize
******************************************************************/
boolean    Transformation::init(void)
{
    int        row,
            col;

    for (row=0 ; row<4 ; row++)
        for (col=0 ; col<4 ; col++)
            if (row == col)
                m[row][col] = 1.;
            else
                m[row][col] = 0.;

    return TRUE;
}

/******************************************************************
*    combines two transformations to produce a new one.  This is
*    done by right-multiplying the first homogeneous transformation
*    matrix with the next one.  That is, the transformations are
*    sequenced from left to right.
******************************************************************/
void    Transformation::combine(Transformation* first,
                                Transformation* next)
{
    int        row,
            col;

    for (row=0 ; row<4 ; row++)
        for (col=0 ; col<4 ; col++)
            m[row][col] =    first->m[row][0] * next->m[0][col] +
                            first->m[row][1] * next->m[1][col] +
                            first->m[row][2] * next->m[2][col] +
                            first->m[row][3] * next->m[3][col];
}

/******************************************************************
*    sets the transformation equal to the argument.
******************************************************************/
void    Transformation::equate(Transformation* nnew)
{
    int        row,
            col;

    for (row=0 ; row<4 ; row++)
        for (col=0 ; col<4 ; col++)
            m[row][col] = nnew->m[row][col];
}

/******************************************************************
*    set translation
******************************************************************/
void    Translation::set(double tx,double ty,double tz)
{
    m[3][0] = tx;
    m[3][1] = ty;
    m[3][2] = tz;
}

/******************************************************************
*    set scaling
******************************************************************/
void    Scaling::set(double sx,double sy,double sz)
{
    m[0][0] = sx;
    m[1][1] = sy;
    m[2][2] = sz;
}

/******************************************************************
*    set rotation about x
******************************************************************/
void    Rotation_X::set(double theta)
{
    double    ct,
            st;

    ct = cos(theta);
    st = sin(theta);

    m[1][1] = ct;
    m[1][2] = st;
    m[2][1] = -st;
    m[2][2] = ct;
}

/******************************************************************
*    set rotation about y
******************************************************************/
void    Rotation_Y::set(double theta)
{
    double    ct,
            st;

    ct = cos(theta);
    st = sin(theta);

    m[0][0] = ct;
    m[0][2] = -st;
    m[2][0] = st;
    m[2][2] = ct;
}

/******************************************************************
*    set rotation about z
******************************************************************/
void    Rotation_Z::set(double theta)
{
    double    ct,
            st;

    ct = cos(theta);
    st = sin(theta);

    m[0][0] = ct;
    m[0][1] = st;
    m[1][0] = -st;
    m[1][1] = ct;
}

/******************************************************************
*    set view transformation - converts from world coordinates to
*    view (camera) coordinates.
*
*    This matrix is obtained by successively multiplying 5 basic tran-
*    sformation matrices: (1) translation by (-x,-y,-z), (2) rotation
*    about the world y axis by (-yaw), (3) rotation about the world x
*    axis by (-pitch), (4) rotation about the world z axis by (-roll),
*    and (5) negation of the x coordinate (to convert from right-handed
*    world coordinates to a left-handed view coordinate system).
*    Ref.: Hearn & Baker, "Computer Graphics", Prentice-Hall, 1986
******************************************************************/
void    World_To_Camera::set(double x,double y,double z,
                            double yaw,double pitch,double roll)
{
    double    cy,
            cp,
            cr,
            sy,
            sp,
            sr,
            k1,
            k2;

    cy = cos(-yaw);
    cp = cos(-pitch);
    cr = cos(-roll);
    sy = sin(-yaw);
    sp = sin(-pitch);
    sr = sin(-roll);
    k1 = -x*cy-z*sy;
    k2 = x*sy-z*cy;

    m[0][0] = -cy*cr+sy*sp*sr;
    m[0][1] = cy*sr+sy*sp*cr;
    m[0][2] = -sy*cp;
    m[0][3] = 0.;

    m[1][0] = cp*sr;
    m[1][1] = cp*cr;
    m[1][2] = sp;
    m[1][3] = 0.;

    m[2][0] = -sy*cr-cy*sp*sr;
    m[2][1] = sy*sr-cy*sp*cr;
    m[2][2] = cy*cp;
    m[2][3] = 0.;

    m[3][0] = -k1*cr-y*cp*sr-k2*sp*sr;
    m[3][1] = k1*sr-y*cp*cr-k2*sp*cr;
    m[3][2] = -y*sp+k2*cp;
    m[3][3] = 1.;
}