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<HTML><HEAD> <TITLE>BBS水木清华站∶精华区</TITLE></HEAD><BODY><CENTER><H1>BBS水木清华站∶精华区</H1></CENTER>发信人: VolVis (arthur), 信区: Java <BR>标 题: Java example(2) <BR>发信站: BBS 水木清华站 (Fri Dec 25 13:37:58 1998) WWW-POST <BR> <BR>Ok , we will talk about another class Matrix, whose function is to do
<BR>matrix computation, such as the roatation along one axis or transform.
<BR>I do think everyone have been familiar with them and needn't to explain
<BR>them.
<BR>
<BR>Java Program:
<BR>/** A conventional 3D matrix object that can transform sets of
<BR> 3D points and perform a variety of manipulations on the transform */
<BR>
<BR>class Matrix3D {
<BR> float xx, xy, xz, xo;
<BR> float yx, yy, yz, yo;
<BR> float zx, zy, zz, zo;
<BR> static final double pi = 3.14159265;
<BR> /** Create a new unit matrix */
<BR> Matrix3D () {
<BR> xx = 1.0f;
<BR> yy = 1.0f;
<BR> zz = 1.0f;
<BR> }
<BR> /** Scale by f in all dimensions */
<BR> void scale(float f) {
<BR> xx *= f;
<BR> xy *= f;
<BR> xz *= f;
<BR> xo *= f;
<BR> yx *= f;
<BR> yy *= f;
<BR> yz *= f;
<BR> yo *= f;
<BR> zx *= f;
<BR> zy *= f;
<BR> zz *= f;
<BR> zo *= f;
<BR> }
<BR> /** Scale along each axis independently */
<BR> void scale(float xf, float yf, float zf) {
<BR> xx *= xf;
<BR> xy *= xf;
<BR> xz *= xf;
<BR> xo *= xf;
<BR> yx *= yf;
<BR> yy *= yf;
<BR> yz *= yf;
<BR> yo *= yf;
<BR> zx *= zf;
<BR> zy *= zf;
<BR> zz *= zf;
<BR> zo *= zf;
<BR> }
<BR> /** Translate the origin */
<BR> void translate(float x, float y, float z) {
<BR> xo += x;
<BR> yo += y;
<BR> zo += z;
<BR> }
<BR> /** rotate theta degrees about the y axis */
<BR> void yrot(double theta) {
<BR> theta *= (pi / 180);
<BR> double ct = Math.cos(theta);
<BR> double st = Math.sin(theta);
<BR>
<BR> float Nxx = (float) (xx * ct + zx * st);
<BR> float Nxy = (float) (xy * ct + zy * st);
<BR> float Nxz = (float) (xz * ct + zz * st);
<BR> float Nxo = (float) (xo * ct + zo * st);
<BR>
<BR> float Nzx = (float) (zx * ct - xx * st);
<BR> float Nzy = (float) (zy * ct - xy * st);
<BR> float Nzz = (float) (zz * ct - xz * st);
<BR> float Nzo = (float) (zo * ct - xo * st);
<BR>
<BR> xo = Nxo;
<BR> xx = Nxx;
<BR> xy = Nxy;
<BR> xz = Nxz;
<BR> zo = Nzo;
<BR> zx = Nzx;
<BR> zy = Nzy;
<BR> zz = Nzz;
<BR> }
<BR> /** rotate theta degrees about the x axis */
<BR> void xrot(double theta) {
<BR> theta *= (pi / 180);
<BR> double ct = Math.cos(theta);
<BR> double st = Math.sin(theta);
<BR>
<BR> float Nyx = (float) (yx * ct + zx * st);
<BR> float Nyy = (float) (yy * ct + zy * st);
<BR> float Nyz = (float) (yz * ct + zz * st);
<BR> float Nyo = (float) (yo * ct + zo * st);
<BR>
<BR> float Nzx = (float) (zx * ct - yx * st);
<BR> float Nzy = (float) (zy * ct - yy * st);
<BR> float Nzz = (float) (zz * ct - yz * st);
<BR> float Nzo = (float) (zo * ct - yo * st);
<BR>
<BR> yo = Nyo;
<BR> yx = Nyx;
<BR> yy = Nyy;
<BR> yz = Nyz;
<BR> zo = Nzo;
<BR> zx = Nzx;
<BR> zy = Nzy;
<BR> zz = Nzz;
<BR> }
<BR> /** rotate theta degrees about the z axis */
<BR> void zrot(double theta) {
<BR> theta *= (pi / 180);
<BR> double ct = Math.cos(theta);
<BR> double st = Math.sin(theta);
<BR>
<BR> float Nyx = (float) (yx * ct + xx * st);
<BR> float Nyy = (float) (yy * ct + xy * st);
<BR> float Nyz = (float) (yz * ct + xz * st);
<BR> float Nyo = (float) (yo * ct + xo * st);
<BR>
<BR> float Nxx = (float) (xx * ct - yx * st);
<BR> float Nxy = (float) (xy * ct - yy * st);
<BR> float Nxz = (float) (xz * ct - yz * st);
<BR> float Nxo = (float) (xo * ct - yo * st);
<BR>
<BR> yo = Nyo;
<BR> yx = Nyx;
<BR> yy = Nyy;
<BR> yz = Nyz;
<BR> xo = Nxo;
<BR> xx = Nxx;
<BR> xy = Nxy;
<BR> xz = Nxz;
<BR> }
<BR> /** Multiply this matrix by a second: M = M*R */
<BR> void mult(Matrix3D rhs) {
<BR> float lxx = xx * rhs.xx + yx * rhs.xy + zx * rhs.xz;
<BR> float lxy = xy * rhs.xx + yy * rhs.xy + zy * rhs.xz;
<BR> float lxz = xz * rhs.xx + yz * rhs.xy + zz * rhs.xz;
<BR> float lxo = xo * rhs.xx + yo * rhs.xy + zo * rhs.xz + rhs.xo;
<BR>
<BR> float lyx = xx * rhs.yx + yx * rhs.yy + zx * rhs.yz;
<BR> float lyy = xy * rhs.yx + yy * rhs.yy + zy * rhs.yz;
<BR> float lyz = xz * rhs.yx + yz * rhs.yy + zz * rhs.yz;
<BR> float lyo = xo * rhs.yx + yo * rhs.yy + zo * rhs.yz + rhs.yo;
<BR>
<BR> float lzx = xx * rhs.zx + yx * rhs.zy + zx * rhs.zz;
<BR> float lzy = xy * rhs.zx + yy * rhs.zy + zy * rhs.zz;
<BR> float lzz = xz * rhs.zx + yz * rhs.zy + zz * rhs.zz;
<BR> float lzo = xo * rhs.zx + yo * rhs.zy + zo * rhs.zz + rhs.zo;
<BR>
<BR> xx = lxx;
<BR> xy = lxy;
<BR> xz = lxz;
<BR> xo = lxo;
<BR>
<BR> yx = lyx;
<BR> yy = lyy;
<BR> yz = lyz;
<BR> yo = lyo;
<BR>
<BR> zx = lzx;
<BR> zy = lzy;
<BR> zz = lzz;
<BR> zo = lzo;
<BR> }
<BR>
<BR> /** Reinitialize to the unit matrix */
<BR> void unit() {
<BR> xo = 0;
<BR> xx = 1;
<BR> xy = 0;
<BR> xz = 0;
<BR> yo = 0;
<BR> yx = 0;
<BR> yy = 1;
<BR> yz = 0;
<BR> zo = 0;
<BR> zx = 0;
<BR> zy = 0;
<BR> zz = 1;
<BR> }
<BR> /** Transform nvert points from v into tv. v contains the input
<BR> coordinates in floating point. Three successive entries in
<BR> the array constitute a point. tv ends up holding the transformed
<BR> points as integers; three successive entries per point */
<BR> void transform(float v[], int tv[], int nvert) {
<BR> float lxx = xx, lxy = xy, lxz = xz, lxo = xo;
<BR> float lyx = yx, lyy = yy, lyz = yz, lyo = yo;
<BR> float lzx = zx, lzy = zy, lzz = zz, lzo = zo;
<BR> for (int i = nvert * 3; (i -= 3) >= 0;) {
<BR> float x = v[i];
<BR> float y = v[i + 1];
<BR> float z = v[i + 2];
<BR> tv[i ] = (int) (x * lxx + y * lxy + z * lxz + lxo);
<BR> tv[i + 1] = (int) (x * lyx + y * lyy + z * lyz + lyo);
<BR> tv[i + 2] = (int) ((x * lzx + y * lzy + z * lzz + lzo)*1000000.0f);
<BR> }
<BR> }
<BR> public String toString() {
<BR> return ("[" + xo + "," + xx + "," + xy + "," + xz + ";"
<BR> + yo + "," + yx + "," + yy + "," + yz + ";"
<BR> + zo + "," + zx + "," + zy + "," + zz + "]");
<BR> }
<BR>}
<BR> <BR> <BR>-- <BR>※ 来源:·BBS 水木清华站 bbs.net.tsinghua.edu.cn·[FROM: 162.105.18.102] <BR><CENTER><H1>BBS水木清华站∶精华区</H1></CENTER></BODY></HTML>⌨️ 快捷键说明
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