[Debian-astro-commits] [gyoto] 81/221: yorick: new example script "matte-painting.i"

[Thibaut Jean-Claude Paumard]

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thibaut pushed a commit to branch master
in repository gyoto.

commit d0d9f0540ffe7af9ff98d415e83d206169e04543
Author: Thibaut Paumard <paumard at users.sourceforge.net>
Date:   Sat Nov 1 18:14:52 2014 +0100

    yorick: new example script "matte-painting.i"
---
 yorick/matte-painting.i | 159 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 159 insertions(+)

diff --git a/yorick/matte-painting.i b/yorick/matte-painting.i
new file mode 100644
index 0000000..88c6538
--- /dev/null
+++ b/yorick/matte-painting.i
@@ -0,0 +1,159 @@
+#!/usr/bin/env yorick
+/*
+    This script examplifies how to perform matte painting with Gyoto,
+    i.e. vizualizing lensing effects on a painted background.
+
+    Copyright 2014 Thibaut Paumard
+
+    This file is part of Gyoto.
+
+    Gyoto is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    Gyoto is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with Gyoto.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "gyoto.i"
+#include "jpeg.i"
+restore, gyoto;
+
+matte=[];
+// To use a jpeg file as matte:
+//   - uncomment the following line;
+//   - set the path to the file you want;
+//   - set x0, y0 and fov0 below.
+//matte=jpeg_read("file_in.jpg")(,,::-1);
+
+// Pixel coordinates of the center of the zone of interest in the
+// JPEG image:
+x0=2000;
+y0=1500;
+// Size in pixel of the zone of the JPEG file that should map the
+// screen field-of-view:
+fov0=3000;
+
+// Choose a metric, set its mass:
+earth_mass=5.9722e24; // mass of the Earth, in kg
+kerrbl=KerrBL(spin=0., mass=0.1*earth_mass, unit="kg");
+kerrks=KerrKS(mass=kerrbl.mass(), spin=kerrbl.spin());
+minkowski=Metric("Minkowski");
+minkowski, mass=kerrbl.mass(), setparameter="Cartesian";
+metric=kerrbl;
+
+// Define the screen (=camera):
+res=128; // resolution of the output image
+scr=Screen(inclination=pi/2, paln=pi, metric=metric, resolution=res);
+scr,distance=1, unit="m"; // camera is at 1m from the BH
+
+// Use an empty Astrobj, just set rmax to 10 meters:
+ao=Astrobj("Complex", rmax=10./metric.unitlength());
+
+// Build a Scenery with this Metric, Screen and Astrobj:
+sc=Scenery(metric=metric, astrobj=ao, screen=scr, nthreads=8);
+
+// Compute the last coordinates of the "escaping" photons
+// (Actually coming from infinity)
+data=sc(,,impactcoords=)(9:,,);
+
+// Transform the photon's 4-velocity into equatorial coordinates
+if (sc.metric().coordkind()==gyoto.coordkind.spherical) {
+
+  t=data(1,,);
+  r=data(2,,);
+  theta=data(3,,);  
+  phi=data(4,,);
+  tdot=data(5,,);
+  rp=rdot=data(6,,);
+  thp=thetadot=data(7,,);
+  php=phidot=data(8,,);
+
+  ind=where(tdot);
+  taup=tdot; taup(ind)=1./tdot(ind);
+  rp =rdot    *taup;
+  php=phidot  *taup;
+  thp=thetadot*taup;
+
+  sth=sin(theta);
+  cth=cos(theta);
+  sph=sin(phi);
+  cph=cos(phi);
+
+  ur= [sth*cph, sth*sph, cth];
+  uth=[cth*cph, cth*sph, -sth];
+  uph=[   -sph,     cph,   0];
+
+  durdph=sth*uph;
+  durdth=uth;
+
+  durdt=php*durdph+thp*durdth;
+
+  v=rp*ur + r*durdt;
+
+  mask0=r<1e200;
+  
+ } else {
+  tdot=data(5,,);
+  xdot=data(6,,);
+  ydot=data(7,,);
+  zdot=data(8,,);
+  v=[xdot, ydot, zdot]/tdot(,,-);
+  mask0=tdot<1e200;
+ }
+
+vproj2=v(,,1)^2+v(,,2)^2
+
+vr=sqrt(vproj2+v(,,3)^2);
+vph=atan(v(,,2), v(,,1));
+vth=atan(sqrt(vproj2), v(,,3));
+
+ind=where(r>1e308);
+
+// A simple analytical matte:
+bg=sin(80*vph)*sin(80*vth);
+if (numberof(ind)) bg(ind)=bg(min, min);
+
+// If a JPEG was provided:
+if (!is_void(matte)) {
+
+  dmatte=dimsof(matte);
+
+  phi0=(vph(0,0)+vph(1,1))*0.5;
+  theta0=(vth(0,0)+vth(1,1))*0.5;
+  Dphi=(vph(0,0)-vph(1,1));
+  Dtheta=(vth(0,0)-vth(1,1));
+
+  x=long((vph-phi0)/Dphi*fov0)+x0;
+  y=long((vth-theta0)/Dtheta*fov0)+y0;
+
+  if (anyof((mask=(x<1)))) x(where(mask))=1;
+  if (anyof((mask=(y<1)))) y(where(mask))=1;
+  if (anyof((mask=(x>dmatte(3))))) x(where(mask))=dmatte(3);
+  if (anyof((mask=(y>dmatte(4))))) y(where(mask))=dmatte(4);
+
+  bg=array(char, 3, res, res);
+  for(k=1; k<=3; ++k) {
+    for (i=1; i<=res; ++i) {
+      for (j=1; j<=res; ++j) {
+        bg(k,i,j)=matte(k,x(i, j),y(i, j));
+      }
+    }
+    bg(k,,) *= mask0;
+  }
+
+ }
+
+// Display the image:
+fma;
+pli, bg;
+
+
+// Possibly, save it as a JPEG:
+//jpeg_write, "file_out.jpg", bg(,,::-1);

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