Moves ClipList code into Manifold.cpp

Build/xcode5/PlayRho.xcodeproj/project.pbxproj

@@ -412,8 +412,6 @@
 		996B7B8D2A6DF25200A8207F /* PoolMemoryResource.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 996B7B8A2A6DF25200A8207F /* PoolMemoryResource.cpp */; };
 		996B7B8F2A6EED6200A8207F /* polymorphic_allocator.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 996B7B8E2A6EED6200A8207F /* polymorphic_allocator.cpp */; };
 		9980D10A29C8ACB700007B35 /* WorldConf.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 9980D10929C8ACB700007B35 /* WorldConf.cpp */; };
-		998A7C012A801C1C00F29B01 /* ClipList.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 998A7BFF2A801C1C00F29B01 /* ClipList.cpp */; };
-		998A7C022A801C1C00F29B01 /* ClipList.hpp in Headers */ = {isa = PBXBuildFile; fileRef = 998A7C002A801C1C00F29B01 /* ClipList.hpp */; };
 		998A7C052A80404600F29B01 /* StatsResource.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 998A7C032A80404600F29B01 /* StatsResource.cpp */; };
 		998A7C062A80404600F29B01 /* StatsResource.hpp in Headers */ = {isa = PBXBuildFile; fileRef = 998A7C042A80404600F29B01 /* StatsResource.hpp */; };
 		998A7C082A814F9300F29B01 /* StatsResource.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 998A7C072A814F9300F29B01 /* StatsResource.cpp */; };
@@ -920,8 +918,6 @@
 		996B7B8A2A6DF25200A8207F /* PoolMemoryResource.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = PoolMemoryResource.cpp; sourceTree = "<group>"; };
 		996B7B8E2A6EED6200A8207F /* polymorphic_allocator.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; path = polymorphic_allocator.cpp; sourceTree = "<group>"; };
 		9980D10929C8ACB700007B35 /* WorldConf.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; path = WorldConf.cpp; sourceTree = "<group>"; };
-		998A7BFF2A801C1C00F29B01 /* ClipList.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; path = ClipList.cpp; sourceTree = "<group>"; };
-		998A7C002A801C1C00F29B01 /* ClipList.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = ClipList.hpp; sourceTree = "<group>"; };
 		998A7C032A80404600F29B01 /* StatsResource.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; path = StatsResource.cpp; sourceTree = "<group>"; };
 		998A7C042A80404600F29B01 /* StatsResource.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = StatsResource.hpp; sourceTree = "<group>"; };
 		998A7C072A814F9300F29B01 /* StatsResource.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; path = StatsResource.cpp; sourceTree = "<group>"; };
@@ -1298,7 +1294,6 @@
 				470F94A51EC4C79B00AA3C82 /* BodyConf.hpp */,
 				474BAB2C1E5D00960058E08A /* BodyConstraint.hpp */,
 				80BB8936141C3E5900F1753A /* ChainShapeConf.hpp */,
-				998A7C002A801C1C00F29B01 /* ClipList.hpp */,
 				476162C71E245C9D002C7FB0 /* CodeDumper.hpp */,
 				99D1BE242AEF1FFD001BA497 /* ContactImpulsesFunction.hpp */,
 				47363E8520027FE2005912B1 /* ContactImpulsesList.hpp */,
@@ -1384,7 +1379,6 @@
 				80BB894D141C3E5900F1753A /* Body.cpp */,
 				470F9B4B1EEF20B6007EF7B6 /* BodyConf.cpp */,
 				80BB8935141C3E5900F1753A /* ChainShapeConf.cpp */,
-				998A7BFF2A801C1C00F29B01 /* ClipList.cpp */,
 				476162C61E245C9D002C7FB0 /* CodeDumper.cpp */,
 				47363E8420027FE2005912B1 /* ContactImpulsesList.cpp */,
 				80BB8963141C3E5900F1753A /* ContactSolver.cpp */,
@@ -1647,7 +1641,6 @@
 				4734B2271DC29F7C00F15E29 /* SimplexEdge.hpp in Headers */,
 				4787D6BB1F2E946E008C115E /* PrismaticJointConf.hpp in Headers */,
 				47C85D1B1F0D9D8D00F70C56 /* Units.hpp in Headers */,
-				998A7C022A801C1C00F29B01 /* ClipList.hpp in Headers */,
 				99D1BE212AEF18F8001BA497 /* ShapeFunction.hpp in Headers */,
 				998A7C0C2A82D55100F29B01 /* Contactable.hpp in Headers */,
 				470F9B181EDF2959007EF7B6 /* Transformation.hpp in Headers */,
@@ -2171,7 +2164,6 @@
 				47363E8920029DFD005912B1 /* Velocity.cpp in Sources */,
 				4787D6BA1F2E946E008C115E /* PrismaticJointConf.cpp in Sources */,
 				4787D6CE1F2EC902008C115E /* MotorJointConf.cpp in Sources */,
-				998A7C012A801C1C00F29B01 /* ClipList.cpp in Sources */,
 				4787D6CA1F2EA3A1008C115E /* GearJointConf.cpp in Sources */,
 				80BB89BE141C3E5900F1753A /* Contact.cpp in Sources */,
 				80BB89C0141C3E5900F1753A /* ContactSolver.cpp in Sources */,

Library/CMakeLists.txt

@@ -207,7 +207,6 @@ set(PLAYRHO_D2_HDRS
     include/playrho/d2/BodyConf.hpp
     include/playrho/d2/BodyConstraint.hpp
     include/playrho/d2/ChainShapeConf.hpp
-    include/playrho/d2/ClipList.hpp
     include/playrho/d2/CodeDumper.hpp
     include/playrho/d2/ContactImpulsesFunction.hpp
     include/playrho/d2/ContactImpulsesList.hpp
@@ -277,7 +276,6 @@ set(PLAYRHO_D2_SRCS
     source/playrho/d2/Body.cpp
     source/playrho/d2/BodyConf.cpp
     source/playrho/d2/ChainShapeConf.cpp
-    source/playrho/d2/ClipList.cpp
     source/playrho/d2/CodeDumper.cpp
     source/playrho/d2/ContactImpulsesList.cpp
     source/playrho/d2/ContactSolver.cpp

Library/source/playrho/d2/Manifold.cpp

@@ -26,7 +26,6 @@
 #include <playrho/StepConf.hpp>
 #include <playrho/Templates.hpp> // for size
 
-#include <playrho/d2/ClipList.hpp>
 #include <playrho/d2/Distance.hpp>
 #include <playrho/d2/DistanceProxy.hpp>
 #include <playrho/d2/Manifold.hpp>
@@ -39,6 +38,69 @@ namespace playrho::d2 {
 
 namespace {
 
+/// @brief Clip vertex.
+/// @details Used for computing contact manifolds.
+struct ClipVertex
+{
+    Length2 v; ///< Vertex of edge or polygon.
+    ContactFeature cf; ///< Contact feature information.
+};
+
+/// @brief Clip list for <code>ClipSegmentToLine</code>.
+/// @see ClipSegmentToLine.
+using ClipList = ArrayList<ClipVertex, MaxManifoldPoints>;
+
+/// Clipping for contact manifolds.
+/// @details This returns an array of points from the given line that are inside of the plane as
+///   defined by a given normal and offset.
+/// @param vIn Clip list of two points defining the line.
+/// @param normal Normal of the plane with which to determine intersection.
+/// @param offset Offset of the plane with which to determine intersection.
+/// @param indexA Index of vertex A.
+/// @return List of zero one or two clip points.
+ClipList ClipSegmentToLine(const ClipList& vIn, const UnitVec& normal, Length offset,
+                           ContactFeature::Index indexA)
+{
+    ClipList vOut;
+
+    if (size(vIn) == 2) // must have two points (for a segment)
+    {
+        // Use Sutherland-Hodgman clipping:
+        //   (https://en.wikipedia.org/wiki/Sutherland%E2%80%93Hodgman_algorithm ).
+
+        // Calculate the distance of end points to the line
+        const auto distance0 = Dot(normal, vIn[0].v) - offset;
+        const auto distance1 = Dot(normal, vIn[1].v) - offset;
+
+        // If the points are behind the plane...
+        // Ideally they are. Then we get face-vertex contact features which are simpler to
+        // calculate. Note that it also helps to avoid changing the contact feature from the
+        // given clip vertices. So the code here also accepts distances that are just slightly
+        // over zero.
+        if (distance0 <= 0_m || AlmostZero(StripUnit(distance0)))
+        {
+            vOut.push_back(vIn[0]);
+        }
+        if (distance1 <= 0_m || AlmostZero(StripUnit(distance1)))
+        {
+            vOut.push_back(vIn[1]);
+        }
+
+        // If we didn't already find two points & the points are on different sides of the plane...
+        if (size(vOut) < 2 && signbit(StripUnit(distance0)) != signbit(StripUnit(distance1)))
+        {
+            // Neither distance0 nor distance1 is 0 and either one or the other is negative (but not both).
+            // Find intersection point of edge and plane
+            // Vertex A is hitting edge B.
+            const auto interp = distance0 / (distance0 - distance1);
+            const auto vertex = vIn[0].v + (vIn[1].v - vIn[0].v) * interp;
+            vOut.push_back(ClipVertex{vertex, GetVertexFaceContactFeature(indexA, vIn[0].cf.indexB)});
+        }
+    }
+
+    return vOut;
+}
+
 constexpr auto face = ContactFeature::e_face;
 constexpr auto vertex = ContactFeature::e_vertex;