work in progress for shape operations
A experimental/Intersection
A experimental/Intersection/Intersections.h
A experimental/Intersection/DataTypes.cpp
A experimental/Intersection/QuadraticReduceOrder.cpp
A experimental/Intersection/IntersectionUtilities.cpp
A experimental/Intersection/CubicIntersection_Tests.h
A experimental/Intersection/LineParameteters_Test.cpp
A experimental/Intersection/ReduceOrder.cpp
A experimental/Intersection/QuadraticIntersection.cpp
A experimental/Intersection/Extrema.h
A experimental/Intersection/CubicIntersection_TestData.h
A experimental/Intersection/QuadraticParameterization_Test.cpp
A experimental/Intersection/TestUtilities.cpp
A experimental/Intersection/CubicRoots.cpp
A experimental/Intersection/QuadraticParameterization.cpp
A experimental/Intersection/QuadraticSubDivide.cpp
A experimental/Intersection/LineIntersection_Test.cpp
A experimental/Intersection/LineIntersection.cpp
A experimental/Intersection/CubicParameterizationCode.cpp
A experimental/Intersection/LineParameters.h
A experimental/Intersection/CubicIntersection.h
A experimental/Intersection/CubeRoot.cpp
A experimental/Intersection/SkAntiEdge.h
A experimental/Intersection/ConvexHull_Test.cpp
A experimental/Intersection/CubicBezierClip_Test.cpp
A experimental/Intersection/CubicIntersection_Tests.cpp
A experimental/Intersection/CubicBezierClip.cpp
A experimental/Intersection/CubicIntersectionT.cpp
A experimental/Intersection/Inline_Tests.cpp
A experimental/Intersection/ReduceOrder_Test.cpp
A experimental/Intersection/QuadraticIntersection_TestData.h
A experimental/Intersection/DataTypes.h
A experimental/Intersection/Extrema.cpp
A experimental/Intersection/EdgeApp.cpp
A experimental/Intersection/CubicIntersection_TestData.cpp
A experimental/Intersection/IntersectionUtilities.h
A experimental/Intersection/CubicReduceOrder.cpp
A experimental/Intersection/CubicCoincidence.cpp
A experimental/Intersection/CubicIntersection_Test.cpp
A experimental/Intersection/CubicIntersection.cpp
A experimental/Intersection/QuadraticUtilities.h
A experimental/Intersection/SkAntiEdge.cpp
A experimental/Intersection/TestUtilities.h
A experimental/Intersection/CubicParameterization_Test.cpp
A experimental/Intersection/LineIntersection.h
A experimental/Intersection/CubicSubDivide.cpp
A experimental/Intersection/CubicParameterization.cpp
A experimental/Intersection/QuadraticBezierClip_Test.cpp
A experimental/Intersection/QuadraticBezierClip.cpp
A experimental/Intersection/BezierClip_Test.cpp
A experimental/Intersection/ConvexHull.cpp
A experimental/Intersection/BezierClip.cpp
A experimental/Intersection/QuadraticIntersection_TestData.cpp
git-svn-id: http://skia.googlecode.com/svn/trunk@3005 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/experimental/Intersection/IntersectionUtilities.h b/experimental/Intersection/IntersectionUtilities.h
new file mode 100644
index 0000000..3dfd311
--- /dev/null
+++ b/experimental/Intersection/IntersectionUtilities.h
@@ -0,0 +1,41 @@
+
+// inline utilities
+/* Returns 0 if negative, 1 if zero, 2 if positive
+*/
+inline int side(double x) {
+ return (x > 0) + (x >= 0);
+}
+
+/* Returns 1 if negative, 2 if zero, 4 if positive
+*/
+inline int sideBit(double x) {
+ return 1 << side(x);
+}
+
+/* Given the set [0, 1, 2, 3], and two of the four members, compute an XOR mask
+ that computes the other two. Note that:
+
+ one ^ two == 3 for (0, 3), (1, 2)
+ one ^ two < 3 for (0, 1), (0, 2), (1, 3), (2, 3)
+ 3 - (one ^ two) is either 0, 1, or 2
+ 1 >> 3 - (one ^ two) is either 0 or 1
+thus:
+ returned == 2 for (0, 3), (1, 2)
+ returned == 3 for (0, 1), (0, 2), (1, 3), (2, 3)
+given that:
+ (0, 3) ^ 2 -> (2, 1) (1, 2) ^ 2 -> (3, 0)
+ (0, 1) ^ 3 -> (3, 2) (0, 2) ^ 3 -> (3, 1) (1, 3) ^ 3 -> (2, 0) (2, 3) ^ 3 -> (1, 0)
+*/
+inline int other_two(int one, int two) {
+ return 1 >> 3 - (one ^ two) ^ 3;
+}
+
+/* Returns -1 if negative, 0 if zero, 1 if positive
+*/
+inline int sign(double x) {
+ return (x > 0) - (x < 0);
+}
+
+inline double interp(double A, double B, double t) {
+ return A + (B - A) * t;
+}