CloudCreateVolume.h

#pragma once
#include <osg/Node>
#include <osgDB/ReadFile> 

#include <string>
#include <vector>

namespace osgCloudyDay
{
        //http://www.softsurfer.com/Archive/algorithm_0105/algorithm_0105.htm#intersect_RayTriangle%28%29
        //    Input:  a ray R, and a triangle T
        //    Output: *I = intersection point (when it exists)
        //    Return: -1 = triangle is degenerate (a segment or point)
        //             0 = disjoint (no intersect)
        //             1 = intersect in unique point I1
        //             2 = are in the same plane
        inline int intersect_RayTriangle( osg::Vec3* R, osg::Vec3* T, osg::Vec3& I )
        {
                osg::Vec3    u, v, n;             // triangle vectors
                osg::Vec3    dir, w0, w;          // ray vectors
                float     r, a, b;             // params to calc ray-plane intersect

                // get triangle edge vectors and plane normal
                u = T[1] - T[0];
                v = T[2] - T[0];
                n = u ^ v;             // cross product
                if (n == osg::Vec3())            // triangle is degenerate
                        return -1;                 // do not deal with this case

                dir = R[1] - R[0];             // ray direction vector
                w0 = R[0] - T[0];
                a = -n * w0;
                b =  n * dir;

                if (fabs(b) < 0.00000001) {     // ray is parallel to triangle plane
                        if (a == 0)  return 2;      // ray lies in triangle plane
                        else return 0;             // ray disjoint from plane
                }

                // get intersect point of ray with triangle plane
                r = a / b;
                if (r < 0.0)                   // ray goes away from triangle
                        return 0;                  // => no intersect
                // for a segment, also test if (r > 1.0) => no intersect

                I = R[0] + (dir * r);           // intersect point of ray and plane

                // is I inside T?
                float    uu, uv, vv, wu, wv, D;
                uu = u * u;
                uv = u * v;
                vv = v * v;
                w = I - T[0];
                wu = w * u;
                wv = w * v;
                D = uv * uv - uu * vv;

                // get and test parametric coords
                float s, t;
                s = (uv * wv - vv * wu) / D;
                if (s < 0.0 || s > 1.0)        // I is outside T
                        return 0;
                t = (uv * wu - uu * wv) / D;
                if (t < 0.0 || (s + t) > 1.0)  // I is outside T
                        return 0;

                return 1;                      // I is in T
        }

        class CloudCreateVolume
        {
        public:
                CloudCreateVolume(void);
                ~CloudCreateVolume(void);

                osg::Node* LoadingVolume(std::string path);

                bool PointInside(osg::Vec3 point);

                std::vector<std::pair<osg::Vec3, osg::Vec3>> m_aabb_boundbox;

        private:
                osg::ref_ptr<osg::Node> object;
        };
}