BBS水木清华站∶精华区

发信人: VolVis (arthur), 信区: Java
标  题: Java example(2)
发信站: BBS 水木清华站 (Fri Dec 25 13:37:58 1998) WWW-POST

Ok , we will talk about another class Matrix, whose function is to do
matrix computation, such as the roatation along one axis or transform.
I do think everyone have been familiar with them and needn't to explain
them.

Java Program:
/** A conventional 3D matrix object that can transform sets of
    3D points and perform a variety of manipulations on the transform */

class Matrix3D {
    float xx, xy, xz, xo;
    float yx, yy, yz, yo;
    float zx, zy, zz, zo;
    static final double pi = 3.14159265;
    /** Create a new unit matrix */
    Matrix3D () {
xx = 1.0f;
yy = 1.0f;
zz = 1.0f;
    }
    /** Scale by f in all dimensions */
    void scale(float f) {
xx *= f;
xy *= f;
xz *= f;
xo *= f;
yx *= f;
yy *= f;
yz *= f;
yo *= f;
zx *= f;
zy *= f;
zz *= f;
zo *= f;
    }
    /** Scale along each axis independently */
    void scale(float xf, float yf, float zf) {
xx *= xf;
xy *= xf;
xz *= xf;
xo *= xf;
yx *= yf;
yy *= yf;
yz *= yf;
yo *= yf;
zx *= zf;
zy *= zf;
zz *= zf;
zo *= zf;
    }
    /** Translate the origin */
    void translate(float x, float y, float z) {
xo += x;
yo += y;
zo += z;
    }
    /** rotate theta degrees about the y axis */
    void yrot(double theta) {
theta *= (pi / 180);
double ct = Math.cos(theta);
double st = Math.sin(theta);

float Nxx = (float) (xx * ct + zx * st);
float Nxy = (float) (xy * ct + zy * st);
float Nxz = (float) (xz * ct + zz * st);
float Nxo = (float) (xo * ct + zo * st);

float Nzx = (float) (zx * ct - xx * st);
float Nzy = (float) (zy * ct - xy * st);
float Nzz = (float) (zz * ct - xz * st);
float Nzo = (float) (zo * ct - xo * st);

xo = Nxo;
xx = Nxx;
xy = Nxy;
xz = Nxz;
zo = Nzo;
zx = Nzx;
zy = Nzy;
zz = Nzz;
    }
    /** rotate theta degrees about the x axis */
    void xrot(double theta) {
theta *= (pi / 180);
double ct = Math.cos(theta);
double st = Math.sin(theta);

float Nyx = (float) (yx * ct + zx * st);
float Nyy = (float) (yy * ct + zy * st);
float Nyz = (float) (yz * ct + zz * st);
float Nyo = (float) (yo * ct + zo * st);

float Nzx = (float) (zx * ct - yx * st);
float Nzy = (float) (zy * ct - yy * st);
float Nzz = (float) (zz * ct - yz * st);
float Nzo = (float) (zo * ct - yo * st);

yo = Nyo;
yx = Nyx;
yy = Nyy;
yz = Nyz;
zo = Nzo;
zx = Nzx;
zy = Nzy;
zz = Nzz;
    }
    /** rotate theta degrees about the z axis */
    void zrot(double theta) {
theta *= (pi / 180);
double ct = Math.cos(theta);
double st = Math.sin(theta);

float Nyx = (float) (yx * ct + xx * st);
float Nyy = (float) (yy * ct + xy * st);
float Nyz = (float) (yz * ct + xz * st);
float Nyo = (float) (yo * ct + xo * st);

float Nxx = (float) (xx * ct - yx * st);
float Nxy = (float) (xy * ct - yy * st);
float Nxz = (float) (xz * ct - yz * st);
float Nxo = (float) (xo * ct - yo * st);

yo = Nyo;
yx = Nyx;
yy = Nyy;
yz = Nyz;
xo = Nxo;
xx = Nxx;
xy = Nxy;
xz = Nxz;
    }
    /** Multiply this matrix by a second: M = M*R */
    void mult(Matrix3D rhs) {
float lxx = xx * rhs.xx + yx * rhs.xy + zx * rhs.xz;
float lxy = xy * rhs.xx + yy * rhs.xy + zy * rhs.xz;
float lxz = xz * rhs.xx + yz * rhs.xy + zz * rhs.xz;
float lxo = xo * rhs.xx + yo * rhs.xy + zo * rhs.xz + rhs.xo;

float lyx = xx * rhs.yx + yx * rhs.yy + zx * rhs.yz;
float lyy = xy * rhs.yx + yy * rhs.yy + zy * rhs.yz;
float lyz = xz * rhs.yx + yz * rhs.yy + zz * rhs.yz;
float lyo = xo * rhs.yx + yo * rhs.yy + zo * rhs.yz + rhs.yo;

float lzx = xx * rhs.zx + yx * rhs.zy + zx * rhs.zz;
float lzy = xy * rhs.zx + yy * rhs.zy + zy * rhs.zz;
float lzz = xz * rhs.zx + yz * rhs.zy + zz * rhs.zz;
float lzo = xo * rhs.zx + yo * rhs.zy + zo * rhs.zz + rhs.zo;

xx = lxx;
xy = lxy;
xz = lxz;
xo = lxo;

yx = lyx;
yy = lyy;
yz = lyz;
yo = lyo;

zx = lzx;
zy = lzy;
zz = lzz;
zo = lzo;
    }

    /** Reinitialize to the unit matrix */
    void unit() {
xo = 0;
xx = 1;
xy = 0;
xz = 0;
yo = 0;
yx = 0;
yy = 1;
yz = 0;
zo = 0;
zx = 0;
zy = 0;
zz = 1;
    }
    /** Transform nvert points from v into tv.  v contains the input
        coordinates in floating point.  Three successive entries in
the array constitute a point.  tv ends up holding the transformed
points as integers; three successive entries per point */
    void transform(float v[], int tv[], int nvert) {
float lxx = xx, lxy = xy, lxz = xz, lxo = xo;
float lyx = yx, lyy = yy, lyz = yz, lyo = yo;
float lzx = zx, lzy = zy, lzz = zz, lzo = zo;
for (int i = nvert * 3; (i -= 3) >= 0;) {
    float x = v[i];
    float y = v[i + 1];
    float z = v[i + 2];
    tv[i    ] = (int) (x * lxx + y * lxy + z * lxz + lxo);
    tv[i + 1] = (int) (x * lyx + y * lyy + z * lyz + lyo);
    tv[i + 2] = (int) ((x * lzx + y * lzy + z * lzz + lzo)*1000000.0f);
}
    }
    public String toString() {
return ("[" + xo + "," + xx + "," + xy + "," + xz + ";"
+ yo + "," + yx + "," + yy + "," + yz + ";"
+ zo + "," + zx + "," + zy + "," + zz + "]");
    }
}

--
※ 来源:·BBS 水木清华站 bbs.net.tsinghua.edu.cn·[FROM: 162.105.18.102]