clipped_view.cxx

#include <cgv/base/base.h>
#include "clipped_view.h"
 
namespace cgv {
    namespace render {
 
clipped_view::clipped_view()
{
    z_near = 0.0001;
    z_far = 100;
}
 
double clipped_view::get_z_near() const 
{
    return z_near; 
}
 
void clipped_view::set_z_near(double z) 
{
    z_near = z; 
}
 
double clipped_view::get_z_far() const 
{
    return z_far; 
}
 
void clipped_view::set_z_far(double z) 
{
    z_far = z; 
}
 
void clipped_view::set_scene_extent(const dbox3& _box)
{
    scene_extent = _box;
}
 
dbox3 clipped_view::get_scene_extent() const
{
    if (scene_extent.is_valid())
        return scene_extent;
    return dbox3(dbox3::pnt_type(-1, -1, -1), dbox3::pnt_type(1, 1, 1));
}
 
void clipped_view::set_default_view()
{
    set_view_dir(0, 0, -1);
    set_view_up_dir(0, 1, 0);
    set_focus(get_scene_extent().get_center());
    set_y_extent_at_focus(get_scene_extent().get_extent().length());
}
 
double clipped_view::get_z_D(double z_eye, double z_near, double z_far)
{
    double C = -(z_far + z_near) / (z_far - z_near);
    double D = -2.0*z_far*z_near / (z_far - z_near);
    return 0.5 - 0.5*(D + C*z_eye) / z_eye;
}
 
void clipped_view::compute_clipping_planes(double& z_near_derived, double& z_far_derived, bool clip_relative_to_extent) const
{
    compute_clipping_planes(*this, z_near_derived, z_far_derived, clip_relative_to_extent);
}
 
void clipped_view::compute_clipping_planes(const cgv::render::view& view, double& z_near_derived, double& z_far_derived, bool clip_relative_to_extent) const
{
    compute_clipping_planes(view.get_eye(), view.get_view_dir(), z_near_derived, z_far_derived, clip_relative_to_extent);
}
 
void clipped_view::compute_clipping_planes(const dvec3& eye, const dvec3& view_dir, double& z_near_derived, double& z_far_derived, bool clip_relative_to_extent) const
{
    double z_eye = dot(eye, view_dir);
 
    // compute the clipping planes based on the eye and scene extent
    z_near_derived = z_near;
    z_far_derived = z_far;
    if (scene_extent.is_valid()) {
        dvec3 sc = scene_extent.get_center();
        dbox3 B(1.25*(scene_extent.get_min_pnt() - sc) + sc,
                1.25*(scene_extent.get_max_pnt() - sc) + sc);
        
        double z_min = dot(B.get_corner(0), view_dir);
        double z_max = z_min;
        for (unsigned int i = 1; i<8; ++i) {
            double new_z = dot(B.get_corner(i), view_dir);
            if (new_z< z_min)
                z_min = new_z;
            if (new_z > z_max)
                z_max = new_z;
        }
        z_min -= z_eye;
        z_max -= z_eye;
        if (z_min > z_near)
            z_near_derived = z_min;
        if (z_max > z_near)
            z_far_derived = z_max;
        
        if (clip_relative_to_extent) {
            z_near_derived *= z_near;
            z_far_derived *= z_far;
        }
    }
    else if (clip_relative_to_extent) {
        z_near_derived = y_extent_at_focus*z_near;
        z_far_derived = y_extent_at_focus*z_far;
    }
}
 
 
    }
}