find_action.h

#pragma once
 
#include <cgv/base/action.h>
 
namespace cgv {
    namespace base {
 
template <class X>
class find_action : public action
{
    X* x;
protected:
    std::vector<X*>& result;
public:
    find_action(std::vector<X*>& _result) : action(true,true), result(_result) {}
    void select(base_ptr p) {
        x = p->get_interface<X>();
    }
    bool begin()
    {
        if (x) {
            result.push_back(x);
            return true;
        }
        else
            return false;
    }
    bool implements_action() const {
        return x != 0;
    }
};
 
template <class X>
void find_interface(base_ptr start, std::vector<X*>& result) {
    find_action<X> fa(result);
    traverser(fa).traverse(start);
}
 
template <class X, typename T>
bool ensure_by_find(X* start, T*& pointer, unsigned i = 0)
{
    if (pointer)
        return true;
 
    std::vector<T*> instances;
    cgv::base::find_interface<T>(base_ptr(start), instances);
    if (instances.empty())
        return false;
    pointer = instances[i < instances.size() ? i : instances.size() - 1];
    return true;
}
 
    }
}