1 files changed, 130 insertions, 0 deletions
diff --git a/src/toys/plane3d.cpp b/src/toys/plane3d.cpp
new file mode 100644
index 0000000..8710869
--- /dev/null
+++ b/src/toys/plane3d.cpp
@@ -0,0 +1,130 @@
+#include <2geom/d2.h>
+#include <2geom/sbasis.h>
+#include <2geom/sbasis-geometric.h>
+#include <2geom/sbasis-2d.h>
+#include <2geom/bezier-to-sbasis.h>
+#include <2geom/transforms.h>
+#include <2geom/sbasis-math.h>
+
+#include <toys/path-cairo.h>
+#include <toys/toy-framework-2.h>
+#include <2geom/path.h>
+#include <2geom/svg-path-parser.h>
+
+#include <gsl/gsl_matrix.h>
+
+#include <vector>
+using std::vector;
+using namespace Geom;
+using namespace std;
+
+class Box3d: public Toy {
+    double tmat[3][4];
+    PointHandle origin_handle;
+    PointSetHandle vanishing_points_handles;
+    PathVector paths_a;
+    
+    void draw(cairo_t *cr, std::ostringstream *notify, int width, int height, bool save, std::ostringstream *timer_stream) override {
+
+        Geom::Point orig = origin_handle.pos;
+	cairo_set_source_rgba (cr, 0., 0.125, 0, 1);
+
+        /* create the transformation matrix for the map  P^3 --> P^2 that has the following effect:
+              (1 : 0 : 0 : 0) --> vanishing point in x direction (= handle #0)
+              (0 : 1 : 0 : 0) --> vanishing point in y direction (= handle #1)
+              (0 : 0 : 1 : 0) --> vanishing point in z direction (= handle #2)
+              (0 : 0 : 0 : 1) --> origin (= handle #3)
+        */
+        for (int j = 0; j < 4; ++j) {
+            tmat[0][j] = vanishing_points_handles.pts[j][0];
+            tmat[1][j] = vanishing_points_handles.pts[j][1];
+            tmat[2][j] = 1;
+        }
+
+        *notify << "Projection matrix:" << endl;
+        for (auto & i : tmat) {
+            for (double j : i) {
+                *notify << j << " ";
+            }
+            *notify << endl;
+        }
+
+        for(const auto & i : paths_a) {
+            Piecewise<D2<SBasis> >  path_a_pw = i.toPwSb();
+
+            D2<Piecewise<SBasis> > B = make_cuts_independent(path_a_pw);
+            Piecewise<SBasis> preimage[4];
+                
+            preimage[0] =  (B[0] - orig[0]) / 100;
+            preimage[1] = -(B[1] - orig[1]) / 100;
+            Piecewise<SBasis> res[3];
+            for (int j = 0; j < 3; ++j) {
+                res[j] = preimage[0] * tmat[j][0]
+                    + preimage[1] * tmat[j][1]
+                    + tmat[j][3];
+            }
+            
+            //if (fabs (res[2]) > 0.000001) {
+            D2<Piecewise<SBasis> > result(divide(res[0],res[2], 2), 
+                                          divide(res[1],res[2], 2));
+            
+            cairo_d2_pw_sb(cr, result);
+            cairo_set_source_rgba (cr, 0., 0.125, 0, 1);
+            cairo_stroke(cr);
+        }
+        
+        Toy::draw(cr, notify, width, height, save,timer_stream);
+    }
+    void first_time(int argc, char** argv) override {
+        const char *path_a_name="ptitle.svgd";
+        if(argc > 1)
+            path_a_name = argv[1];
+        paths_a = read_svgd(path_a_name);
+        assert(paths_a.size() > 0);
+
+        // Finite images of the three vanishing points and the origin
+        handles.push_back(&origin_handle);
+        handles.push_back(&vanishing_points_handles);
+        vanishing_points_handles.push_back(550,350);
+        vanishing_points_handles.push_back(150,300);
+        vanishing_points_handles.push_back(380,40);
+        vanishing_points_handles.push_back(340,450);
+        // plane origin
+        origin_handle.pos = Point(180,65);
+    }
+    //int should_draw_bounds() {return 1;}
+    
+    Geom::Point proj_image (cairo_t *cr, const double pt[4], const vector<Geom::Point> &/*handles*/)
+    {
+        double res[3];
+        for (int j = 0; j < 3; ++j) {
+            res[j] = 0;
+            for (int i = 0; i < 3; ++i)
+                res[j] += tmat[j][i] * pt[i];
+        }
+        if (fabs (res[2]) > 0.000001) {
+            Geom::Point result = Geom::Point (res[0]/res[2], res[1]/res[2]);
+            draw_handle(cr, result);
+            return result;
+        }
+        assert(0); // unclipped point
+        return Geom::Point(0,0);
+    }
+
+};
+
+int main(int argc, char **argv) {
+    init(argc, argv, new Box3d);
+    return 0;
+}
+
+/*
+  Local Variables:
+  mode:c++
+  c-file-style:"stroustrup"
+  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
+  indent-tabs-mode:nil
+  fill-column:99
+  End:
+*/
+// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :