1 files changed, 137 insertions, 0 deletions
diff --git a/experimental/Intersection/ReduceOrder_Test.cpp b/experimental/Intersection/ReduceOrder_Test.cpp
new file mode 100644
index 0000000000..04aea1afa6
--- /dev/null
+++ b/experimental/Intersection/ReduceOrder_Test.cpp
@@ -0,0 +1,137 @@
+#include "CubicIntersection.h"
+#include "CubicIntersection_TestData.h"
+#include "CubicIntersection_Tests.h"
+#include "TestUtilities.h"
+
+void ReduceOrder_Test() {
+    size_t index;
+    Cubic reduce;
+    int order;
+    enum {
+        RunAll,
+        RunPointDegenerates,
+        RunNotPointDegenerates,
+        RunLines,
+        RunNotLines,
+        RunModEpsilonLines,
+        RunLessEpsilonLines,
+        RunNegEpsilonLines,
+        RunQuadraticLines,
+        RunQuadraticModLines,
+        RunComputedLines,
+        RunNone
+    } run = RunAll;
+    int firstTestIndex = 0;
+#if 0
+    run = RunComputedLines;
+    firstTestIndex = 18;
+#endif
+    int firstPointDegeneratesTest = run == RunAll ? 0 : run == RunPointDegenerates ? firstTestIndex : INT_MAX;
+    int firstNotPointDegeneratesTest = run == RunAll ? 0 : run == RunNotPointDegenerates ? firstTestIndex : INT_MAX;
+    int firstLinesTest = run == RunAll ? 0 : run == RunLines ? firstTestIndex : INT_MAX;
+    int firstNotLinesTest = run == RunAll ? 0 : run == RunNotLines ? firstTestIndex : INT_MAX;
+    int firstModEpsilonTest = run == RunAll ? 0 : run == RunModEpsilonLines ? firstTestIndex : INT_MAX;
+    int firstLessEpsilonTest = run == RunAll ? 0 : run == RunLessEpsilonLines ? firstTestIndex : INT_MAX;
+    int firstNegEpsilonTest = run == RunAll ? 0 : run == RunNegEpsilonLines ? firstTestIndex : INT_MAX;
+    int firstQuadraticLineTest = run == RunAll ? 0 : run == RunQuadraticLines ? firstTestIndex : INT_MAX;
+    int firstQuadraticModLineTest = run == RunAll ? 0 : run == RunQuadraticModLines ? firstTestIndex : INT_MAX;
+    int firstComputedLinesTest = run == RunAll ? 0 : run == RunComputedLines ? firstTestIndex : INT_MAX;
+    
+    for (index = firstPointDegeneratesTest; index < pointDegenerates_count; ++index) {
+        const Cubic& cubic = pointDegenerates[index];
+        order = reduceOrder(cubic, reduce, kReduceOrder_QuadraticsAllowed);
+        if (order != 1) {
+            printf("[%d] pointDegenerates order=%d\n", (int) index, order);
+        }
+    }
+    for (index = firstNotPointDegeneratesTest; index < notPointDegenerates_count; ++index) {
+        const Cubic& cubic = notPointDegenerates[index];
+        order = reduceOrder(cubic, reduce, kReduceOrder_QuadraticsAllowed);
+        if (order == 1) {
+            printf("[%d] notPointDegenerates order=%d\n", (int) index, order);
+        }
+    }
+    for (index = firstLinesTest; index < lines_count; ++index) {
+        const Cubic& cubic = lines[index];
+        order = reduceOrder(cubic, reduce, kReduceOrder_QuadraticsAllowed);
+        if (order != 2) {
+            printf("[%d] lines order=%d\n", (int) index, order);
+        }
+    }
+    for (index = firstNotLinesTest; index < notLines_count; ++index) {
+        const Cubic& cubic = notLines[index];
+        order = reduceOrder(cubic, reduce, kReduceOrder_QuadraticsAllowed);
+        if (order == 2) {
+            printf("[%d] notLines order=%d\n", (int) index, order);
+        }
+    }
+    for (index = firstModEpsilonTest; index < modEpsilonLines_count; ++index) {
+        const Cubic& cubic = modEpsilonLines[index];
+        order = reduceOrder(cubic, reduce, kReduceOrder_QuadraticsAllowed);
+        if (order == 2) {
+            printf("[%d] line mod by epsilon order=%d\n", (int) index, order);
+        }
+    }
+    for (index = firstLessEpsilonTest; index < lessEpsilonLines_count; ++index) {
+        const Cubic& cubic = lessEpsilonLines[index];
+        order = reduceOrder(cubic, reduce, kReduceOrder_QuadraticsAllowed);
+        if (order != 2) {
+            printf("[%d] line less by epsilon/2 order=%d\n", (int) index, order);
+        }
+    }
+    for (index = firstNegEpsilonTest; index < negEpsilonLines_count; ++index) {
+        const Cubic& cubic = negEpsilonLines[index];
+        order = reduceOrder(cubic, reduce, kReduceOrder_QuadraticsAllowed);
+        if (order != 2) {
+            printf("[%d] line neg by epsilon/2 order=%d\n", (int) index, order);
+        }
+    }
+    for (index = firstQuadraticLineTest; index < quadraticLines_count; ++index) {
+        const Quadratic& quad = quadraticLines[index];
+        Cubic cubic;
+        quad_to_cubic(quad, cubic);
+        order = reduceOrder(cubic, reduce, kReduceOrder_QuadraticsAllowed);
+        if (order != 2) {
+            printf("[%d] line quad order=%d\n", (int) index, order);
+        }
+    }
+    for (index = firstQuadraticModLineTest; index < quadraticModEpsilonLines_count; ++index) {
+        const Quadratic& quad = quadraticModEpsilonLines[index];
+        Cubic cubic;
+        quad_to_cubic(quad, cubic);
+        order = reduceOrder(cubic, reduce, kReduceOrder_QuadraticsAllowed);
+        if (order != 3) {
+            printf("[%d] line mod quad order=%d\n", (int) index, order);
+        }
+    }
+    
+    // test if computed line end points are valid
+    for (index = firstComputedLinesTest; index < lines_count; ++index) {
+        const Cubic& cubic = lines[index];
+        bool controlsInside = controls_inside(cubic);        
+        order = reduceOrder(cubic, reduce, kReduceOrder_QuadraticsAllowed);
+        if (reduce[0].x == reduce[1].x && reduce[0].y == reduce[1].y) {
+            printf("[%d] line computed ends match order=%d\n", (int) index, order);
+        }
+        if (controlsInside) {
+            if (       reduce[0].x != cubic[0].x && reduce[0].x != cubic[3].x
+                    || reduce[0].y != cubic[0].y && reduce[0].y != cubic[3].y
+                    || reduce[1].x != cubic[0].x && reduce[1].x != cubic[3].x
+                    || reduce[1].y != cubic[0].y && reduce[1].y != cubic[3].y) {
+                printf("[%d] line computed ends order=%d\n", (int) index, order);
+            }
+        } else {
+            // binary search for extrema, compare against actual results
+                // while a control point is outside of bounding box formed by end points, split
+            _Rect bounds = {DBL_MAX, DBL_MAX, -DBL_MAX, -DBL_MAX};
+            find_tight_bounds(cubic, bounds);
+            if (       !approximately_equal(reduce[0].x, bounds.left) && !approximately_equal(reduce[0].x, bounds.right)
+                    || !approximately_equal(reduce[0].y, bounds.top) && !approximately_equal(reduce[0].y, bounds.bottom)
+                    || !approximately_equal(reduce[1].x, bounds.left) && !approximately_equal(reduce[1].x, bounds.right)
+                    || !approximately_equal(reduce[1].y, bounds.top) && !approximately_equal(reduce[1].y, bounds.bottom)) {
+                printf("[%d] line computed tight bounds order=%d\n", (int) index, order);
+            }
+            
+        }
+    }
+}