diff -r 5df69eb50182 -r f116b63c4844 src/ringFinder.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/ringFinder.cpp Sat Aug 29 17:07:39 2015 +0300 @@ -0,0 +1,224 @@ +/* + * LDForge: LDraw parts authoring CAD + * Copyright (C) 2013, 2014 Teemu Piippo + * + * This program 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 3 of the License, or + * (at your option) any later version. + * + * This program 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 this program. If not, see . + */ + +#include "ringFinder.h" +#include "miscallenous.h" + +RingFinder g_RingFinder; + +RingFinder::RingFinder() {} + +// ============================================================================= +// +bool RingFinder::findRingsRecursor (double r0, double r1, Solution& currentSolution) +{ + // Don't recurse too deep. + if (m_stack >= 5) + return false; + + // Find the scale and number of a ring between r1 and r0. + assert (r1 >= r0); + double scale = r1 - r0; + double num = r0 / scale; + + // If the ring number is integral, we have found a fitting ring to r0 -> r1! + if (IsIntegral (num)) + { + Component cmp; + cmp.scale = scale; + cmp.num = (int) round (num); + currentSolution.addComponent (cmp); + + // If we're still at the first recursion, this is the only + // ring and there's nothing left to do. Guess we found the winner. + if (m_stack == 0) + { + m_solutions.push_back (currentSolution); + return true; + } + } + else + { + // Try find solutions by splitting the ring in various positions. + if (IsZero (r1 - r0)) + return false; + + double interval; + + // Determine interval. The smaller delta between radii, the more precise + // interval should be used. We can't really use a 0.5 increment when + // calculating rings to 10 -> 105... that would take ages to process! + if (r1 - r0 < 0.5) + interval = 0.1; + else if (r1 - r0 < 10) + interval = 0.5; + else if (r1 - r0 < 50) + interval = 1; + else + interval = 5; + + // Now go through possible splits and try find rings for both segments. + for (double r = r0 + interval; r < r1; r += interval) + { + Solution sol = currentSolution; + + m_stack++; + bool res = findRingsRecursor (r0, r, sol) and findRingsRecursor (r, r1, sol); + m_stack--; + + if (res) + { + // We succeeded in finding radii for this segment. If the stack is 0, this + // is the first recursion to this function. Thus there are no more ring segments + // to process and we can add the solution. + // + // If not, when this function ends, it will be called again with more arguments. + // Accept the solution to this segment by setting currentSolution to sol, and + // return true to continue processing. + if (m_stack == 0) + m_solutions.push_back (sol); + else + { + currentSolution = sol; + return true; + } + } + } + + return false; + } + + return true; +} + +// +// This is the main algorithm of the ring finder. It tries to use math +// to find the one ring between r0 and r1. If it fails (the ring number +// is non-integral), it finds an intermediate radius (ceil of the ring +// number times scale) and splits the radius at this point, calling this +// function again to try find the rings between r0 - r and r - r1. +// +// This does not always yield into usable results. If at some point r == +// r0 or r == r1, there is no hope of finding the rings, at least with +// this algorithm, as it would fall into an infinite recursion. +// +bool RingFinder::findRings (double r0, double r1) +{ + m_solutions.clear(); + Solution sol; + + // If we're dealing with fractional radii, try upscale them into integral + // ones. This should yield in more reliable and more optimized results. + // For instance, using r0=1.5, r1=3.5 causes the algorithm to fail but + // r0=3, r1=7 (scaled up by 2) yields a 2-component solution. We can then + // downscale the radii back by dividing the scale fields of the solution + // components. + double scale = 1.0; + + if (not IsZero (scale = r0 - floor (r0)) or not IsZero (scale = r1 - floor (r1))) + { + double r0f = r0 / scale; + double r1f = r1 / scale; + + if (IsIntegral (r0f) and IsIntegral (r1f)) + { + r0 = r0f; + r1 = r1f; + } + // If the numbers are both at most one-decimal fractions, we can use a scale of 10 + elif (IsIntegral (r0 * 10) and IsIntegral (r1 * 10)) + { + scale = 0.1; + r0 *= 10; + r1 *= 10; + } + } + else + { + scale = 1.0; + } + + // Recurse in and try find solutions. + findRingsRecursor (r0, r1, sol); + + // If we had upscaled our radii, downscale back now. + if (scale != 1.0) + { + for (Solution& sol : m_solutions) + sol.scaleComponents (scale); + } + + // Compare the solutions and find the best one. The solution class has an operator> + // overload to compare two solutions. + m_bestSolution = null; + + for (Solution const& sol : m_solutions) + { + if (m_bestSolution == null or sol.isSuperiorTo (m_bestSolution)) + m_bestSolution = / + } + + return (m_bestSolution != null); +} + +// +// Compares this solution with @other and determines which +// one is superior. +// +// A solution is considered superior if solution has less +// components than the other one. If both solution have an +// equal amount components, the solution with a lesser maximum +// ring number is found superior, as such solutions should +// yield less new primitives and cleaner definitions. +// +// The solution which is found superior to every other solution +// will be the one returned by RingFinder::bestSolution(). +// +bool RingFinder::Solution::isSuperiorTo (const Solution* other) const +{ + // If one solution has less components than the other one, it is definitely + // better. + if (getComponents().size() != other->getComponents().size()) + return getComponents().size() < other->getComponents().size(); + + // Calculate the maximum ring number. Since the solutions have equal + // ring counts, the solutions with lesser maximum rings should result + // in cleaner code and less new primitives, right? + int maxA = 0, + maxB = 0; + + for (int i = 0; i < getComponents().size(); ++i) + { + maxA = Max (getComponents()[i].num, maxA); + maxB = Max (other->getComponents()[i].num, maxB); + } + + if (maxA != maxB) + return maxA < maxB; + + // Solutions have equal rings and equal maximum ring numbers. Let's + // just say this one is better, at this point it does not matter which + // one is chosen. + return true; +} + +void RingFinder::Solution::scaleComponents (double scale) +{ + for (Component& cmp : m_components) + cmp.scale *= scale; +}