experimental/Intersection/LineCubicIntersection_Test.cpp

#include "CubicIntersection.h"
#include "Intersection_Tests.h"
#include "Intersections.h"
#include "LineUtilities.h"
#include "TestUtilities.h"

struct lineCubic {
    Cubic cubic;
    _Line line;
} lineCubicTests[] = {
    {{{0, 0}, {0, 1}, {0, 1}, {1, 1}}, {{0, 1}, {1, 0}}}
};

size_t lineCubicTests_count = sizeof(lineCubicTests) / sizeof(lineCubicTests[0]);

const int firstLineCubicIntersectionTest = 0;

void LineCubicIntersection_Test() {
    for (size_t index = firstLineCubicIntersectionTest; index < lineCubicTests_count; ++index) {
        const Cubic& cubic = lineCubicTests[index].cubic;
        const _Line& line = lineCubicTests[index].line;
        Cubic reduce1;
        _Line reduce2;
        int order1 = reduceOrder(cubic, reduce1, kReduceOrder_NoQuadraticsAllowed);
        int order2 = reduceOrder(line, reduce2);
        if (order1 < 4) {
            printf("[%d] cubic order=%d\n", (int) index, order1);
        }
        if (order2 < 2) {
            printf("[%d] line order=%d\n", (int) index, order2);
        }
        if (order1 == 4 && order2 == 2) {
            Intersections intersections;
            intersectStart(reduce1, reduce2, intersections);
            if (intersections.intersected()) {
                for (int pt = 0; pt < intersections.used(); ++pt) {
                    double tt1 = intersections.fT[0][pt];
                    double tx1, ty1;
                    xy_at_t(cubic, tt1, tx1, ty1);
                    double tt2 = intersections.fT[1][pt];
                    double tx2, ty2;
                    xy_at_t(line, tt2, tx2, ty2);
                    if (!approximately_equal(tx1, tx2)) {
                        printf("%s [%d,%d] x!= t1=%g (%g,%g) t2=%g (%g,%g)\n",
                            __FUNCTION__, (int)index, pt, tt1, tx1, ty1, tt2, tx2, ty2);
                    }
                    if (!approximately_equal(ty1, ty2)) {
                        printf("%s [%d,%d] y!= t1=%g (%g,%g) t2=%g (%g,%g)\n",
                            __FUNCTION__, (int)index, pt, tt1, tx1, ty1, tt2, tx2, ty2);
                    }
                }
            }
        }
    }
}