Initial commit

1 files changed, 132 insertions, 0 deletions

diff --git a/graphics/epix/samples/lighting.flx b/graphics/epix/samples/lighting.flx
new file mode 100644
index 0000000000..80997bebeb
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+++ b/graphics/epix/samples/lighting.flx
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+/* -*-flix-*- */
+// compile with flix -I. [-DAXES] lighting.flx
+// in a directory containing lighting.h
+#include "epix.h"
+#include "lighting.h"
+using namespace ePiX;
+
+// mesh intervals for torus
+int N1(36), N2(12);
+
+// torus
+P F(double x, double y)
+{
+  double R(5-2*Sin(M_PI*y/N2));
+  return P(R*Cos(2*M_PI*x/N1), R*Sin(2*M_PI*x/N1), 2*Cos(M_PI*y/N2));
+}
+
+int main(int argc, char* argv[])
+{
+  if (argc == 3)
+    {
+      char* arg;
+      double temp1, temp2;
+      temp1=strtod(argv[1], &arg);
+      temp2=strtod(argv[2], &arg);
+
+      tix()=temp1/temp2;
+    }
+  picture(P(-10,-10),P(10,10), "4x4in");
+
+  begin();
+  set_crop();
+
+  backing(Black());
+
+  domain R(P(0,N2), P(N1,2*N2), mesh(N1,N2), mesh(2*N1,2*N2));
+
+  // manual layering below may require adjustment if the camera is moved
+  camera.at(P(4,6,4));
+  camera.range(16);
+
+#ifdef AXES
+  yellow();
+  label(P(8,0,0), P(-2,-2), "$\\mathbf{x}$", bl);
+  label(P(0,8,0), P( 2,-2), "$\\mathbf{y}$", br);
+  label(P(0,0,8), P( 0, 4), "$\\mathbf{z}$", t);
+#endif
+
+  // draw grid only
+  pen(Green(), 0.15);
+  plot(F, R);
+
+  // axes (with solid arrowheads) and shaded surface
+#ifdef AXES
+  arrow(P(0,0,0), P(8,0,0));
+  arrow(P(0,0,0), P(0,8,0));
+  arrow(P(0,0,0), P(0,0,8));
+#endif
+
+  rgb(0.8, 0.4, 0);
+  fill();
+  Color chip_color(White());     // true color of torus
+  Color ambient(RGB(1,0.75,0));  // ambient light
+
+  Fog fog(White(), 0.0125);
+
+  // spot light location
+  P spot_at(sph(10, M_PI_4, 2*M_PI*tix())); // traverses a longitude
+
+  // P spot_b=P(5,0,0)+cyl(10, 2*M_PI*tix(), 5); // or latitude
+  // P spot_b(5,-5,10);                        // or stays put
+  Spot spot(Blue(), spot_at);
+
+  std::vector<Chip> surf_mesh;
+  // torus, surface reflectivity .75
+  for (int i=0; i<N1; ++i)
+    for (int j=0; j<N2; ++j)
+      surf_mesh.push_back(Chip(F(i,j), F(i+1,j), F(i+1,j+1), F(i,j+1),
+			       0.75, chip_color));
+
+  sort(surf_mesh.begin(), surf_mesh.end(), chip_distance());
+
+#ifdef SHOW_SPOT
+  // mark spot light's location
+  if (spot_at.x2() <= 0)
+    {
+      blue();
+      box(spot.m_loc);
+    }
+#endif
+
+  // draw shaded surface mesh
+  for (unsigned int i=0; i<surf_mesh.size(); ++i)
+    surf_mesh.at(i).draw(fog, spot, ambient);
+
+#ifdef SHOW_SPOT
+  if (spot_at.x2() > 0)
+    {
+      blue();
+      box(spot.m_loc);
+    }
+#endif
+
+#ifdef AXES
+  // re-draw hidden portions
+  green();
+  line(P(3,0,0), P(8,0,0));
+  line(P(0,3,0), P(0,8,0));
+  line(P(0,0,0), P(0,0,8));
+#endif
+
+  fill(false);
+  // redraw front portion of mesh partially covered by solid surface
+  pen(Green(), 0.15);
+  plot(F, R.resize1(0, 0.25*N1));
+
+  // labels
+  base(White(), 1);
+  line(P(3,0,6), F(0,0.25*N2));
+  line(P(6,0,4), F(0,-0.25*N2));
+
+  label_border(Green(0.6), "0.5pt");
+  label_color(Black());
+  label_mask(RGB(1,0.8,0.2));
+
+  font_size("footnotesize");
+  masklabel(P(3,0,6), P(0,0), "Total curvature $-\\pi$", t);
+  masklabel(P(6,0,4), P(0,0), "Total curvature $\\pi$", t);
+
+  pst_format();
+  end();
+}