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[lsystem3d.git] / src / ruleset.cpp

// Copyright (C) 2006 Erik Dahlberg
// 
// This file is part of LSystem3D.
// 
// LSystem3D is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
// 
// LSystem3D is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
// 
// You should have received a copy of the GNU General Public License
// along with LSystem3D; if not, write to the Free Software
// Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA




#include <cmath>
#include <ctime>

#include <string>
#include <utility>

#include "rule.h"
#include "ruleset.h"



/**
 * Constructor
 */
RuleSet::RuleSet()
{
    srand(time(NULL));
}



/**
 * Destructor
 */
RuleSet::~RuleSet()
{
}



/**
 * Clear rule set
 */
void RuleSet::clear()
{
    _rules.clear();
}



/**
 * Add one rule
 * @param rule the rule
 */
void RuleSet::addRule(Rule rule)
{
    _rules.insert(make_pair(rule.getName(), rule));
}



/**
 * Get one rule with repect of probability factor
 * @param name the rule name
 * @return the rule
 */
Rule RuleSet::findRule(string ruleName)
{
    // TODO: clean up...
    
    
    int numRules = _rules.count(ruleName);
    Rule selectedRule;
    
    if (numRules == 0)
    {
        // no rule with this name
        selectedRule.setProbability(0.0);
    }
    else if (numRules == 1)
    {
        // only one rule with this name
        selectedRule = _rules.find(ruleName)->second;
    }
    else
    {
        // many rules with this name
        
        
        // find ranges
        
        // TODO: int ok?
        int ranges[numRules + 1];
        
        double lastRange = ranges[0] = 0;
        int index = 1;
        
        // TODO: move to addRule()
        pair<rulemap::iterator, rulemap::iterator> interval = _rules.equal_range(ruleName);
        for (rulemap::iterator it = interval.first; it != interval.second; it++)
        {
            // calculate and store ranges
            lastRange += it->second.getProbability() * RAND_MAX;
            ranges[index++] = (int)lastRange;
        }
        
        ranges[numRules] = RAND_MAX;
        
        
        // choose random range
        
        int selection = 0;
        int random = rand();
        
        for (int i = 0; i < numRules; i++)
        {
            if (random >= ranges[i] && random <= ranges[i + 1])
            {
                // in range
                selection = i;
                
                break;
            }
        }
        
        
        // make selection
        
        rulemap::iterator it = interval.first;
        for (int i = 0; i < selection; i++)
        {
            it++;
        }
        selectedRule = it->second;
    }
    
    
    return selectedRule;
}



/**
 * Get all rules
 * @return the rules
 */
rulemap RuleSet::getRules()
{
    return _rules;
}