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Diffstat (limited to 'src/toys/box3d.cpp')
| -rw-r--r-- | src/toys/box3d.cpp | 153 |
1 files changed, 153 insertions, 0 deletions
diff --git a/src/toys/box3d.cpp b/src/toys/box3d.cpp new file mode 100644 index 0000000..06d2e6a --- /dev/null +++ b/src/toys/box3d.cpp @@ -0,0 +1,153 @@ +#include <toys/toy-framework-2.h> + +#include <vector> +using std::vector; +using namespace Geom; +using namespace std; + +class Box3d: public Toy { + Point orig; + + double tmat[3][4]; + double c[8][4]; + Point corners[8]; + + PointHandle origin_handle; + PointSetHandle vanishing_points_handles, axes_handles; + + void draw(cairo_t *cr, std::ostringstream *notify, int width, int height, bool save, std::ostringstream *timer_stream) override { + Geom::Point dir(1,-2); + + cairo_set_source_rgba (cr, 0., 0.125, 0, 1); + + // draw vertical lines for the VP sliders and keep the sliders at their horizontal positions + draw_slider_lines (cr); + axes_handles.pts[0][0] = 30; + axes_handles.pts[1][0] = 45; + axes_handles.pts[2][0] = 60; + + /* 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; + } + + // draw the projective images of the box's corners + for (int i = 0; i < 8; ++i) { + corners[i] = proj_image (cr, c[i]); + } + draw_box(cr, corners); + cairo_set_line_width (cr, 2); + cairo_stroke(cr); + + Toy::draw(cr, notify, width, height, save,timer_stream); + } + void first_time(int /*argc*/, char** /*argv*/) override { + // Finite images of the three vanishing points and the origin + handles.push_back(&origin_handle); + handles.push_back(&vanishing_points_handles); + handles.push_back(&axes_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); + + // Handles for moving in axes directions + axes_handles.push_back(30,300); + axes_handles.push_back(45,300); + axes_handles.push_back(60,300); + + // Box corners + for (int i = 0; i < 8; ++i) { + c[i][0] = ((i & 1) ? 1 : 0); + c[i][1] = ((i & 2) ? 1 : 0); + c[i][2] = ((i & 4) ? 1 : 0); + c[i][3] = 1; + } + + orig = origin_handle.pos; + } + Geom::Point proj_image (cairo_t *cr, const double pt[4]) { + double res[3]; + for (int j = 0; j < 3; ++j) { + res[j] = + tmat[j][0] * (pt[0] - (axes_handles.pts[0][1]-300)/100) + + tmat[j][1] * (pt[1] - (axes_handles.pts[1][1]-300)/100) + + tmat[j][2] * (pt[2] - (axes_handles.pts[2][1]-300)/100) + + tmat[j][3] * pt[3]; + } + 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); + } + + void draw_box (cairo_t *cr, Geom::Point corners[8]) { + cairo_move_to(cr,corners[0]); + cairo_line_to(cr,corners[1]); + cairo_line_to(cr,corners[3]); + cairo_line_to(cr,corners[2]); + cairo_close_path(cr); + + cairo_move_to(cr,corners[4]); + cairo_line_to(cr,corners[5]); + cairo_line_to(cr,corners[7]); + cairo_line_to(cr,corners[6]); + cairo_close_path(cr); + + for(int i = 0 ; i < 4; i++) { + cairo_move_to(cr,corners[i]); + cairo_line_to(cr,corners[i+4]); + } + } + + void draw_slider_lines (cairo_t *cr) { + cairo_move_to(cr, Geom::Point(20,300)); + cairo_line_to(cr, Geom::Point(70,300)); + + for(int i = 0; i < 3; i++) { + cairo_move_to(cr, Geom::Point(30 + 15*i,00)); + cairo_line_to(cr, Geom::Point(30 + 15*i,450)); + } + + cairo_set_line_width (cr, 1); + cairo_set_source_rgba (cr, 0.2, 0.2, 0.2, 1); + cairo_stroke(cr); + } +}; + +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 : |