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mirror of https://github.com/zenorogue/hyperrogue.git synced 2024-11-17 18:54:48 +00:00
hyperrogue/hypgraph.cpp
2018-04-04 01:19:21 +02:00

800 lines
20 KiB
C++

// Hyperbolic Rogue -- hyperbolic graphics
// Copyright (C) 2011-2018 Zeno Rogue, see 'hyper.cpp' for details
ld ghx, ghy, ghgx, ghgy;
hyperpoint ghpm = C0;
void ghcheck(hyperpoint &ret, const hyperpoint &H) {
if(hypot(ret[0]-ghx, ret[1]-ghy) < hypot(ghgx-ghx, ghgy-ghy)) {
ghpm = H; ghgx = ret[0]; ghgy = ret[1];
}
}
void camrotate(ld& hx, ld& hy) {
ld cam = vid.camera_angle * M_PI / 180;
GLfloat cc = cos(cam);
GLfloat ss = sin(cam);
ld ux = hx, uy = hy * cc + ss, uz = cc - ss * hy;
hx = ux / uz, hy = uy / uz;
}
hyperpoint gethyper(ld x, ld y) {
ld hx = (x - vid.xcenter) / vid.radius;
ld hy = (y - vid.ycenter) / vid.radius;
if(pmodel) {
ghx = hx, ghy = hy;
return ghpm;
}
if(vid.camera_angle) camrotate(hx, hy);
if(euclid)
return hpxy(hx * (1 + vid.alpha), hy * (1 + vid.alpha));
ld hr = hx*hx+hy*hy;
if(hr > .9999 && !sphere) return Hypc;
// hz*hz-(hx/(hz+alpha))^2 - (hy/(hz+alpha))^2 =
// hz*hz-hr*(hz+alpha)^2 == 1
// hz*hz - hr*hr*hz*Hz
ld A, B, C;
ld curv = sphere ? 1 : -1;
A = 1+curv*hr;
B = 2*hr*vid.alpha*-curv;
C = 1 - curv*hr*vid.alpha*vid.alpha;
// Az^2 - Bz = C
B /= A; C /= A;
// z^2 - Bz = C
// z^2 - Bz + (B^2/4) = C + (B^2/4)
// z = (B/2) + sqrt(C + B^2/4)
ld rootsign = 1;
if(sphere && vid.alpha > 1) rootsign = -1;
ld hz = B / 2 + rootsign * sqrt(C + B*B/4);
hyperpoint H;
H[0] = hx * (hz+vid.alpha);
H[1] = hy * (hz+vid.alpha);
H[2] = hz;
return H;
}
void ballmodel(hyperpoint& ret, double alpha, double d, double zl) {
hyperpoint H = ypush(geom3::camera) * xpush(d) * ypush(zl) * C0;
ld tzh = vid.ballproj + H[2];
ld ax = H[0] / tzh;
ld ay = H[1] / tzh;
ld ball = vid.ballangle * M_PI / 180;
ld ca = cos(alpha), sa = sin(alpha);
ld cb = cos(ball), sb = sin(ball);
ret[0] = ax * ca;
ret[1] = ay * cb + ax * sa * sb;
ret[2] = ax * sa * cb - ay * sb;
}
void apply_depth(hyperpoint &f, ld z) {
if(vid.usingGL)
f[2] = z;
else {
z = z * vid.radius;
ld mul = stereo::scrdist / (stereo::scrdist + z);
f[0] = f[0] * mul;
f[1] = f[1] * mul;
f[2] = vid.xres * stereo::eyewidth() / 2 / vid.radius + stereo::ipd * mul / 2;
}
}
bool hypot_zlev(bool zlev_used, ld& d, ld zlev, ld& df, ld& zf, ld &z) {
if(!zlev_used) {
df = 1; zf = 0;
return false;
}
else {
// (0,0,1) -> (0, sin z, cos z) -> (sin d cos z, sin z, cos d cos z)
ld z = geom3::factor_to_lev(zlev);
ld tz = sin_auto(z);
ld td = sin_auto(abs(d)) * cos_auto(z);
ld h = hypot(td, tz);
if(d > 0)
d = hypot_auto(d, z);
else
d = -hypot_auto(d, z);
zf = tz / h, df = td / h;
return true;
}
}
bool hypot_zlev(bool zlev_used, ld& d, ld zlev, ld& df, ld& zf) {
ld z;
return hypot_zlev(zlev_used, d, zlev, df, zf, z);
}
void applymodel(hyperpoint H, hyperpoint& ret) {
ld tz = euclid ? (1+vid.alpha) : vid.alpha+H[2];
if(tz < BEHIND_LIMIT && tz > -BEHIND_LIMIT) tz = BEHIND_LIMIT;
if(pmodel == mdUnchanged) {
for(int i=0; i<3; i++) ret[i] = H[i] / vid.radius;
return;
}
if(pmodel == mdBall) {
ld zlev = zlevel(H);
using namespace hyperpoint_vec;
H = H / zlev;
ld zl = geom3::depth-geom3::factor_to_lev(zlev);
double alpha = atan2(H[1], H[0]);
double d = hdist0(H);
ballmodel(ret, alpha, d, zl);
ghcheck(ret,H);
return;
}
if(pmodel == mdHemisphere) {
ld ball = vid.ballangle * M_PI / 180;
using namespace hyperpoint_vec;
switch(cgclass) {
case gcHyperbolic: {
ld zl = zlevel(H);
ret = H / H[2];
ret[2] = sqrt(1 - sqhypot2(ret));
ret = ret * (1 + (zl - 1) * ret[2]);
break;
}
case gcEuclid: {
// stereographic projection to a sphere
auto hd = hdist0(H) / vid.euclid_to_sphere;
if(hd == 0) ret = hpxyz(0, 0, -1);
else {
ld x = 2 * hd / (1 + hd * hd);
ld y = x / hd;
ret = H * x / hd / vid.euclid_to_sphere;
ret[2] = (1 - y);
ret = ret * (1 + (H[2]-1) * y / vid.euclid_to_sphere);
}
break;
}
case gcSphere: {
ret = H;
break;
}
}
ret = rotmatrix(M_PI/2 + ball, 1, 2) * ret;
ghcheck(ret, H);
return;
}
if(pmodel == mdHyperboloid) {
ld ball = -vid.ballangle * M_PI / 180;
ld cb = cos(ball), sb = sin(ball);
ret[0] = H[0] / 3;
ret[1] = (1 - H[2]) / 3 * cb - H[1] / 3 * sb;
ret[2] = -(-H[1] / 3 * cb - (1 - H[2]) / 3 * sb);
ghcheck(ret,H);
return;
}
if(pmodel == mdDisk) {
if(!vid.camera_angle) {
ret[0] = H[0] / tz;
ret[1] = H[1] / tz;
ret[2] = vid.xres / vid.radius * stereo::eyewidth() / 2 - stereo::ipd / tz / 2;
}
else {
ld tx = H[0];
ld ty = H[1];
ld cam = vid.camera_angle * M_PI / 180;
GLfloat cc = cos(cam);
GLfloat ss = sin(cam);
ld ux = tx, uy = ty * cc - ss * tz, uz = tz * cc + ss * ty;
ret[0] = ux / uz;
ret[1] = uy / uz;
ret[2] = vid.xres / vid.radius * stereo::eyewidth() / 2 - stereo::ipd / uz / 2;
}
return;
}
ld zlev = 1;
bool zlev_used = false;
if(wmspatial || mmspatial) {
zlev = zlevel(H);
using namespace hyperpoint_vec;
zlev_used = !((zlev > 1-1e-6 && zlev < 1+1e-6));
if(zlev_used) H /= zlev;
}
if(pmodel == mdTwoPoint || mdBandAny() || pmodel == mdSinusoidal) {
// map to plane
if(false) {
auto p = vid.twopoint_param;
ld dleft = hdist(H, xpush(-p) * C0);
ld dright = hdist(H, xpush(p) * C0);
ld yf = 1, zf = 0;
if(zlev_used) {
ld y_orig = asin_auto(H[1]);
ld z;
hypot_zlev(true, y_orig, zlev, yf, zf, z);
dleft = hypot_auto(dleft, z);
dright = hypot_auto(dright, z);
}
ld x = (dright*dright-dleft*dleft) / 4 / p;
ld y = sqrt(dleft * dleft - (x-p)*(x-p) + 1e-9);
x = -x;
ret = hpxyz(x/M_PI, y*(H[1]<0?-1:1)*yf/M_PI, 0);
if(zlev_used && stereo::active())
apply_depth(ret, y * zf / M_PI);
}
else {
ld x, y, yf, zf;
y = asin_auto(H[1]);
x = asin_auto(H[0] / cos_auto(y));
if(sphere) {
if(H[2] < 0 && x > 0) x = M_PI - x;
else if(H[2] < 0 && x <= 0) x = -M_PI - x;
}
hypot_zlev(zlev_used, y, zlev, yf, zf);
if(pmodel == mdTwoPoint) {
auto p = vid.twopoint_param;
ld dleft = hypot_auto(x-p, y);
ld dright = hypot_auto(x+p, y);
x = (dright*dright-dleft*dleft) / 4 / p;
y = (y>0?1:-1) * sqrt(dleft * dleft - (x-p)*(x-p) + 1e-9);
}
else if(pmodel == mdBand) switch(cgclass) {
case gcSphere:
y = atanh(sin(y));
x *= 2; y *= 2;
break;
case gcHyperbolic:
y = 2 * atan(tanh(y/2));
x *= 2; y *= 2;
break;
case gcEuclid:
y = y;
y *= 2; x *= 2;
break;
}
else if(pmodel == mdBandEquiarea)
y = sin_auto(y);
else if(pmodel == mdSinusoidal)
x *= cos_auto(y);
ret = hpxyz(x / M_PI, y * yf / M_PI, 0);
if(zlev_used && stereo::active())
apply_depth(ret, y * zf / M_PI);
}
ghcheck(ret, H);
return;
}
if(mdAzimuthalEqui()) {
ld rad = sqrt(H[0] * H[0] + H[1] * H[1]);
if(rad == 0) rad = 1;
ld d = hdist0(H);
ld yf, zf;
hypot_zlev(zlev_used, d, zlev, yf, zf);
// 4 pi / 2pi = M_PI
if(pmodel == 6 && sphere)
d = sqrt(2*(1 - cos(d))) * M_PI / 2;
else if(pmodel == 6 && !euclid)
d = sqrt(2*(cosh(d) - 1)) / 1.5;
ret[0] = d * yf * H[0] / rad / M_PI;
ret[1] = d * yf * H[1] / rad / M_PI;
ret[2] = 0;
if(zlev_used && stereo::active())
apply_depth(ret, d * zf / M_PI);
ghcheck(ret,H);
return;
}
tz = H[2]+vid.alpha;
if(pmodel == mdPolygonal || pmodel == mdPolynomial) {
pair<long double, long double> p = polygonal::compute(H[0]/tz, H[1]/tz);
ret[0] = p.first;
ret[1] = p.second;
ret[2] = 0;
ghcheck(ret,H);
return;
}
if(pmodel == mdHalfplane) {
// Poincare to half-plane
ld x0, y0;
x0 = H[0] / tz;
y0 = H[1] / tz;
if(conformal::lower_halfplane) x0 = -x0, y0 = -y0;
y0 += 1;
double rad = x0*x0 + y0*y0;
y0 /= rad;
x0 /= rad;
y0 -= .5;
if(conformal::lower_halfplane) x0 = -x0, y0 = -y0;
ret[0] = x0;
if(wmspatial || mmspatial) {
if(conformal::lower_halfplane) y0 /= zlev;
else y0 *= zlev;
}
ret[1] = (conformal::lower_halfplane?-1:1) - y0;
ret[2] = 0;
if(zlev != 1 && stereo::active())
apply_depth(ret, -y0 * geom3::factor_to_lev(zlev));
ghcheck(ret,H);
return;
}
}
// game-related graphics
transmatrix View; // current rotation, relative to viewctr
transmatrix cwtV = Id; // player-relative view
transmatrix sphereflip; // on the sphere, flip
heptspin viewctr; // heptagon and rotation where the view is centered at
bool playerfound; // has player been found in the last drawing?
#define eurad crossf
double q3 = sqrt(double(3));
bool outofmap(hyperpoint h) {
if(euclid)
return h[2] < .5; // false; // h[0] * h[0] + h[1] * h[1] > 15 * eurad;
else if(sphere)
return h[2] < .1 && h[2] > -.1 && h[1] > -.1 && h[1] < .1 && h[0] > -.1 && h[0] < .1;
else
return h[2] < .5;
}
hyperpoint mirrorif(const hyperpoint& V, bool b) {
if(b) return Mirror*V;
else return V;
}
transmatrix mirrorif(const transmatrix& V, bool b) {
if(b) return V*Mirror;
else return V;
}
// -1 if away, 0 if not away
int away(const transmatrix& V2) {
return (intval(C0, V2 * xpush0(.1)) > intval(C0, tC0(V2))) ? -1 : 0;
}
/* double zgrad(double f1, double f2, int nom, int den) {
using namespace geom3;
ld fo1 = factor_to_lev(f1);
ld fo2 = factor_to_lev(f2);
return lev_to_factor(fo1 + (fo2-fo1) * nom / den);
} */
double zgrad0(double l1, double l2, int nom, int den) {
using namespace geom3;
return lev_to_factor(l1 + (l2-l1) * nom / den);
}
bool behindsphere(const hyperpoint& h) {
if(!sphere) return false;
if(vid.alpha > 1) {
if(h[2] > -1/vid.alpha) return true;
}
if(vid.alpha <= 1) {
if(h[2] < -.8) return true;
}
return false;
}
ld to01(ld a0, ld a1, ld x) {
if(x < a0) return 0;
if(x > a1) return 1;
return (x-a0) / (a1-a0);
}
ld spherity(const hyperpoint& h) {
if(!sphere) return 1;
if(vid.alpha > 1) {
return to01(1/vid.alpha, 1, -h[2]);
}
if(vid.alpha <= 1) {
return to01(-1.5, 1, h[2]);
}
return 1;
}
bool behindsphere(const transmatrix& V) {
return behindsphere(tC0(V));
}
ld spherity(const transmatrix& V) {
return spherity(tC0(V));
}
bool confusingGeometry() {
return elliptic || quotient == 1 || torus;
}
transmatrix actualV(const heptspin& hs, const transmatrix& V) {
return (hs.spin || nonbitrunc) ? V * spin(hs.spin*2*M_PI/S7 + (nonbitrunc ? M_PI:0) + whirl::alpha) : V;
}
namespace whirl {
/*
void drawrec(cell *c, const transmatrix& V) {
if(dodrawcell(c))
drawcell(c, V, 0, false);
for(int i=0; i<c->type; i++) {
cell *c2 = c->mov[i];
if(!c2) continue;
if(c2->mov[0] != c) continue;
if(c2 == c2->master->c7) continue;
transmatrix V1 = V * ddspin(c, i) * xpush(crossf) * iddspin(c2, 0) * spin(M_PI);
drawrec(c2, V1);
}
} */
void drawrec(cell *c, const transmatrix& V, whirl::loc at, int dir, int maindir) {
if(dodrawcell(c)) {
drawcell(c, V * Tf[maindir][at.first&31][at.second&31][fix6(dir)], 0, false);
}
for(int i=0; i<c->type; i++) {
cell *c2 = c->mov[i];
if(!c2) continue;
if(c2->mov[0] != c) continue;
if(c2 == c2->master->c7) continue;
drawrec(c2, V, at + eudir(dir+i), dir + i + 3, maindir);
}
}
void drawrec(cell *c, const transmatrix& V) {
if(dodrawcell(c))
drawcell(c, V, 0, false);
for(int i=0; i<c->type; i++) {
cell *c2 = c->mov[i];
if(!c2) continue;
if(c2->mov[0] != c) continue;
if(c2 == c2->master->c7) continue;
drawrec(c2, V, whirl::loc(1,0), 3, i);
}
}
}
void drawrec(const heptspin& hs, int lev, hstate s, const transmatrix& V) {
// shmup::calc_relative_matrix(cwt.c, hs.h);
cell *c = hs.h->c7;
transmatrix V10;
const transmatrix& V1 = hs.mirrored ? (V10 = V * Mirror) : V;
if(whirl::whirl) {
whirl::drawrec(c, actualV(hs, V1));
}
else if(dodrawcell(c)) {
reclevel = maxreclevel - lev;
transmatrix V2 = actualV(hs, V1);
drawcell(c, V2, 0, hs.mirrored);
}
if(lev <= 0) return;
if(!nonbitrunc) for(int d=0; d<S7; d++) {
int ds = fixrot(hs.spin + d);
reclevel = maxreclevel - lev + 1;
// createMov(c, ds);
if(c->mov[ds] && c->spn(ds) == 0 && dodrawcell(c->mov[ds])) {
drawcell(c->mov[ds], V1 * hexmove[d], 0, hs.mirrored ^ c->mirror(ds));
}
}
if(lev <= 1) return;
for(int d=0; d<S7; d++) {
hstate s2 = transition(s, d);
if(s2 == hsError) continue;
heptspin hs2 = hs + d + wstep;
drawrec(hs2, lev-2, s2, V * heptmove[d]);
}
}
int mindx=-7, mindy=-7, maxdx=7, maxdy=7;
transmatrix eumove(ld x, ld y) {
transmatrix Mat = Id;
Mat[2][2] = 1;
if(a4) {
Mat[0][2] += x * eurad;
Mat[1][2] += y * eurad;
}
else {
Mat[0][2] += (x + y * .5) * eurad;
// Mat[2][0] += (x + y * .5) * eurad;
Mat[1][2] += y * q3 /2 * eurad;
// Mat[2][1] += y * q3 /2 * eurad;
}
ld v = a4 ? 1 : q3;
while(Mat[0][2] <= -16384 * eurad) Mat[0][2] += 32768 * eurad;
while(Mat[0][2] >= 16384 * eurad) Mat[0][2] -= 32768 * eurad;
while(Mat[1][2] <= -16384 * v * eurad) Mat[1][2] += 32768 * v * eurad;
while(Mat[1][2] >= 16384 * v * eurad) Mat[1][2] -= 32768 * v * eurad;
return Mat;
}
transmatrix eumove(int vec) {
int x, y;
tie(x,y) = vec_to_pair(vec);
return eumove(x, y);
}
transmatrix eumovedir(int d) {
if(a4) {
d = d & 3;
switch(d) {
case 0: return eumove(1,0);
case 1: return eumove(0,1);
case 2: return eumove(-1,0);
case 3: return eumove(0,-1);
}
}
else {
d = fix6(d);
switch(d) {
case 0: return eumove(1,0);
case 1: return eumove(0,1);
case 2: return eumove(-1,1);
case 3: return eumove(-1,0);
case 4: return eumove(0,-1);
case 5: return eumove(1,-1);
}
}
return eumove(0,0);
}
ld matrixnorm(const transmatrix& Mat) {
return Mat[0][2] * Mat[0][2] + Mat[1][2] * Mat[1][2];
}
void drawEuclidean() {
DEBB(DF_GRAPH, (debugfile,"drawEuclidean\n"));
sphereflip = Id;
if(!centerover.c) centerover = cwt;
// printf("centerover = %p player = %p [%d,%d]-[%d,%d]\n", lcenterover, cwt.c,
// mindx, mindy, maxdx, maxdy);
int pvec = cellwalker_to_vec(centerover);
int minsx = mindx-1, maxsx=maxdx+1, minsy=mindy-1, maxsy=maxdy+1;
mindx=maxdx=mindy=maxdy=0;
transmatrix View0 = View;
ld cellrad = vid.radius / (1 + vid.alpha);
ld centerd = matrixnorm(View0);
for(int dx=minsx; dx<=maxsx; dx++)
for(int dy=minsy; dy<=maxsy; dy++) {
torusconfig::torus_cx = dx;
torusconfig::torus_cy = dy;
reclevel = eudist(dx, dy);
cellwalker cw = vec_to_cellwalker(pvec + euclid_getvec(dx, dy));
transmatrix Mat = eumove(dx,dy);
if(!cw.c) continue;
Mat = View0 * Mat;
if(true) {
ld locald = matrixnorm(Mat);
if(locald < centerd) centerd = locald, centerover = cw, View = View0 * eumove(dx, dy);
}
// Mat[0][0] = -1;
// Mat[1][1] = -1;
// Mat[2][0] = x*x/10;
// Mat[2][1] = y*y/10;
// Mat = Mat * xpush(x-30) * ypush(y-30);
int cx, cy, shift;
getcoord0(tC0(Mat), cx, cy, shift);
if(cx >= 0 && cy >= 0 && cx < vid.xres && cy < vid.yres) {
if(dx < mindx) mindx = dx;
if(dy < mindy) mindy = dy;
if(dx > maxdx) maxdx = dx;
if(dy > maxdy) maxdy = dy;
}
if(cx >= -cellrad && cy >= -cellrad && cx < vid.xres+cellrad && cy < vid.yres+cellrad)
if(dodrawcell(cw.c)) {
drawcell(cw.c, cw.mirrored ? Mat * Mirror : Mat, cw.spin, cw.mirrored);
}
}
}
void spinEdge(ld aspd) {
if(downspin > aspd) downspin = aspd;
if(downspin < -aspd) downspin = -aspd;
View = spin(downspin) * View;
}
void centerpc(ld aspd) {
if(vid.sspeed >= 4.99) aspd = 1000;
DEBB(DF_GRAPH, (debugfile,"center pc\n"));
hyperpoint H = ypush(-vid.yshift) * sphereflip * tC0(cwtV);
ld R = H[0] == 0 && H[1] == 0 ? 0 : hdist0(H); // = sqrt(H[0] * H[0] + H[1] * H[1]);
if(R < 1e-9) {
// either already centered or direction unknown
/* if(playerfoundL && playerfoundR) {
} */
spinEdge(aspd);
fixmatrix(View);
return;
}
if(euclid) {
// Euclidean
aspd *= (2+3*R*R);
if(aspd > R) aspd = R;
View[0][2] -= cwtV[0][2] * aspd / R;
View[1][2] -= cwtV[1][2] * aspd / R;
}
else {
aspd *= (1+R+(shmup::on?1:0));
if(R < aspd) {
View = gpushxto0(H) * View;
}
else
View = rspintox(H) * xpush(-aspd) * spintox(H) * View;
fixmatrix(View);
spinEdge(aspd);
}
}
void optimizeview() {
DEBB(DF_GRAPH, (debugfile,"optimize view\n"));
int turn = 0;
ld best = INF;
transmatrix TB = Id;
for(int i=-1; i<S7; i++) {
ld trot = -i * M_PI * 2 / (S7+.0);
transmatrix T = i < 0 ? Id : spin(trot) * xpush(tessf) * pispin;
hyperpoint H = View * tC0(T);
if(H[2] < best) best = H[2], turn = i, TB = T;
}
if(turn >= 0) {
View = View * TB;
fixmatrix(View);
viewctr = viewctr + turn + wstep;
}
}
void addball(ld a, ld b, ld c) {
hyperpoint h;
ballmodel(h, a, b, c);
for(int i=0; i<3; i++) h[i] *= vid.radius;
curvepoint(h);
}
void ballgeometry() {
queuereset(vid.usingGL ? mdDisk : mdUnchanged, PPR_CIRCLE);
for(int i=0; i<60; i++)
addball(i * M_PI/30, 10, 0);
for(double d=10; d>=-10; d-=.2)
addball(0, d, 0);
for(double d=-10; d<=10; d+=.2)
addball(0, d, geom3::depth);
addball(0, 0, -geom3::camera);
addball(0, 0, geom3::depth);
addball(0, 0, -geom3::camera);
addball(0, -10, 0);
addball(0, 0, -geom3::camera);
queuecurve(darkena(0xFF, 0, 0x80), 0, PPR_CIRCLE);
queuereset(pmodel, PPR_CIRCLE);
}
void resetview() {
DEBB(DF_GRAPH, (debugfile,"reset view\n"));
View = Id;
// EUCLIDEAN
if(!euclid)
viewctr.h = cwt.c->master,
viewctr.spin = cwt.spin;
else centerover = cwt;
cwtV = Id;
// SDL_LockSurface(s);
// SDL_UnlockSurface(s);
}
void panning(hyperpoint hf, hyperpoint ht) {
View =
rgpushxto0(hf) * rgpushxto0(gpushxto0(hf) * ht) * gpushxto0(hf) * View;
playermoved = false;
}
void fullcenter() {
if(playerfound && false) centerpc(INF);
else {
bfs();
resetview();
drawthemap();
centerpc(INF);
}
playermoved = true;
}
transmatrix screenpos(ld x, ld y) {
transmatrix V = Id;
V[0][2] += (x - vid.xcenter) / vid.radius * (1+vid.alpha);
V[1][2] += (y - vid.ycenter) / vid.radius * (1+vid.alpha);
return V;
}
transmatrix atscreenpos(ld x, ld y, ld size) {
transmatrix V = Id;
V[0][2] += (x - vid.xcenter);
V[1][2] += (y - vid.ycenter);
V[0][0] = size * 2 * hcrossf / crossf;
V[1][1] = size * 2 * hcrossf / crossf;
V[2][2] = stereo::scrdist;
return V;
}