public void Set(b2ManifoldPoint m) { m_localPoint.SetV(m.m_localPoint); m_normalImpulse = m.m_normalImpulse; m_tangentImpulse = m.m_tangentImpulse; m_id.Set(m.m_id); }
public int pointCount; //< the number of manifold points public b2Manifold() { points = new b2ManifoldPoint[b2Settings.b2_maxManifoldPoints]; for (int i = 0; i < points.Length; i++) { points[i] = new b2ManifoldPoint(); } }
public b2ManifoldPoint[] CopyPoints() { b2ManifoldPoint[] copy = new b2ManifoldPoint[points.Length]; points.CopyTo(copy, 0); return(copy); }
/// Compute the collision manifold between two polygons. // Find edge normal of max separation on A - return if separating axis is found // Find edge normal of max separation on B - return if separation axis is found // Choose reference edge as min(minA, minB) // Find incident edge // Clip // The normal points from 1 to 2 public static void b2CollidePolygons(ref b2Manifold manifold, b2PolygonShape polyA, ref b2Transform xfA, b2PolygonShape polyB, ref b2Transform xfB) { manifold.pointCount = 0; float totalRadius = polyA.Radius + polyB.Radius; int edgeA = 0; float separationA = b2FindMaxSeparation(out edgeA, polyA, ref xfA, polyB, ref xfB); if (separationA > totalRadius) return; int edgeB = 0; float separationB = b2FindMaxSeparation(out edgeB, polyB, ref xfB, polyA, ref xfA); if (separationB > totalRadius) return; b2PolygonShape poly1; // reference polygon b2PolygonShape poly2; // incident polygon b2Transform xf1, xf2; int edge1; // reference edge byte flip; const float k_relativeTol = 0.98f; const float k_absoluteTol = 0.001f; if (separationB > k_relativeTol * separationA + k_absoluteTol) { poly1 = polyB; poly2 = polyA; xf1 = xfB; xf2 = xfA; edge1 = edgeB; manifold.type = b2ManifoldType.e_faceB; flip = 1; } else { poly1 = polyA; poly2 = polyB; xf1 = xfA; xf2 = xfB; edge1 = edgeA; manifold.type = b2ManifoldType.e_faceA; flip = 0; } b2ClipVertex[] incidentEdge = new b2ClipVertex[2]; b2FindIncidentEdge(incidentEdge, poly1, xf1, edge1, poly2, xf2); int count1 = poly1.VertexCount; b2Vec2[] vertices1 = poly1.Vertices; int iv1 = edge1; int iv2 = edge1 + 1 < count1 ? edge1 + 1 : 0; b2Vec2 v11 = vertices1[iv1]; b2Vec2 v12 = vertices1[iv2]; b2Vec2 localTangent = v12 - v11; localTangent.Normalize(); b2Vec2 localNormal = localTangent.UnitCross(); // b2Math.b2Cross(localTangent, 1.0f); b2Vec2 planePoint = 0.5f * (v11 + v12); b2Vec2 tangent = b2Math.b2Mul(xf1.q, localTangent); b2Vec2 normal = tangent.UnitCross(); // b2Math.b2Cross(tangent, 1.0f); v11 = b2Math.b2Mul(xf1, v11); v12 = b2Math.b2Mul(xf1, v12); // Face offset. float frontOffset = b2Math.b2Dot(ref normal, ref v11); // Side offsets, extended by polytope skin thickness. float sideOffset1 = -b2Math.b2Dot(ref tangent, ref v11) + totalRadius; float sideOffset2 = b2Math.b2Dot(ref tangent, ref v12) + totalRadius; // Clip incident edge against extruded edge1 side edges. b2ClipVertex[] clipPoints1 = new b2ClipVertex[2]; b2ClipVertex[] clipPoints2 = new b2ClipVertex[2]; int np; // Clip to box side 1 np = b2ClipSegmentToLine(clipPoints1, incidentEdge, -tangent, sideOffset1, (byte)iv1); if (np < 2) return; // Clip to negative box side 1 np = b2ClipSegmentToLine(clipPoints2, clipPoints1, tangent, sideOffset2, (byte)iv2); if (np < 2) { return; } // Now clipPoints2 contains the clipped points. manifold.localNormal = localNormal; manifold.localPoint = planePoint; int pointCount = 0; for (int i = 0; i < b2Settings.b2_maxManifoldPoints; ++i) { float separation = b2Math.b2Dot(ref normal, ref clipPoints2[i].v) - frontOffset; if (separation <= totalRadius) { b2ManifoldPoint cp = manifold.points[pointCount]; cp.localPoint = b2Math.b2MulT(xf2, clipPoints2[i].v); cp.id = clipPoints2[i].id; if (flip != 0) { // Swap features b2ContactFeature cf = cp.id; cp.id.indexA = cf.indexB; cp.id.indexB = cf.indexA; cp.id.typeA = cf.typeB; cp.id.typeB = cf.typeA; } manifold.points[pointCount] = cp; ++pointCount; } } manifold.pointCount = pointCount; }
// Algorithm: // 1. Classify v1 and v2 // 2. Classify polygon centroid as front or back // 3. Flip normal if necessary // 4. Initialize normal range to [-pi, pi] about face normal // 5. Adjust normal range according to adjacent edges // 6. Visit each separating axes, only accept axes within the range // 7. Return if _any_ axis indicates separation // 8. Clip public void Collide(b2Manifold manifold, b2EdgeShape edgeA, ref b2Transform xfA, b2PolygonShape polygonB, ref b2Transform xfB) { m_xf = b2Math.b2MulT(xfA, xfB); m_centroidB = b2Math.b2Mul(ref m_xf, ref polygonB.Centroid); m_v0 = edgeA.Vertex0; m_v1 = edgeA.Vertex1; m_v2 = edgeA.Vertex2; m_v3 = edgeA.Vertex3; bool hasVertex0 = edgeA.HasVertex0; bool hasVertex3 = edgeA.HasVertex3; b2Vec2 edge1;// = m_v2 - m_v1; edge1.x = m_v2.x - m_v1.x; edge1.y = m_v2.y - m_v1.y; edge1.Normalize(); m_normal1.Set(edge1.y, -edge1.x); b2Vec2 cenMinusV1;// = m_centroidB - m_v1; cenMinusV1.x = m_centroidB.x - m_v1.x; cenMinusV1.y = m_centroidB.y - m_v1.y; float offset1 = m_normal1.x * cenMinusV1.x + m_normal1.y * cenMinusV1.y;// b2Math.b2Dot(ref m_normal1, ref cenMinusV1); float offset0 = 0.0f, offset2 = 0.0f; bool convex1 = false, convex2 = false; // Is there a preceding edge? if (hasVertex0) { b2Vec2 edge0;// = m_v1 - m_v0; edge0.x = m_v1.x - m_v0.x; edge0.y = m_v1.y - m_v0.y; edge0.Normalize(); m_normal0.Set(edge0.y, -edge0.x); convex1 = b2Math.b2Cross(ref edge0, ref edge1) >= 0.0f; b2Vec2 cenMinusV0;// = m_centroidB - m_v0; cenMinusV0.x = m_centroidB.x - m_v0.x; cenMinusV0.y = m_centroidB.y - m_v0.y; offset0 = m_normal0.x * cenMinusV0.x + m_normal0.y * cenMinusV0.y; // b2Math.b2Dot(ref m_normal0, ref cenMinusV0); } // Is there a following edge? if (hasVertex3) { b2Vec2 edge2;// = m_v3 - m_v2; edge2.x = m_v3.x - m_v2.x; edge2.y = m_v3.y - m_v2.y; edge2.Normalize(); m_normal2.Set(edge2.y, -edge2.x); convex2 = b2Math.b2Cross(ref edge1, ref edge2) > 0.0f; b2Vec2 tmp; tmp.x = m_centroidB.x - m_v2.x; tmp.y = m_centroidB.y - m_v2.y; offset2 = m_normal2.x * tmp.x + m_normal2.y * tmp.y;// b2Math.b2Dot(m_normal2, m_centroidB - m_v2); } // Determine front or back collision. Determine collision normal limits. if (hasVertex0 && hasVertex3) { if (convex1 && convex2) { m_front = offset0 >= 0.0f || offset1 >= 0.0f || offset2 >= 0.0f; if (m_front) { m_normal = m_normal1; m_lowerLimit = m_normal0; m_upperLimit = m_normal2; } else { m_normal = -m_normal1; m_lowerLimit = -m_normal1; m_upperLimit = -m_normal1; } } else if (convex1) { m_front = offset0 >= 0.0f || (offset1 >= 0.0f && offset2 >= 0.0f); if (m_front) { m_normal = m_normal1; m_lowerLimit = m_normal0; m_upperLimit = m_normal1; } else { m_normal = -m_normal1; m_lowerLimit = -m_normal2; m_upperLimit = -m_normal1; } } else if (convex2) { m_front = offset2 >= 0.0f || (offset0 >= 0.0f && offset1 >= 0.0f); if (m_front) { m_normal = m_normal1; m_lowerLimit = m_normal1; m_upperLimit = m_normal2; } else { m_normal = -m_normal1; m_lowerLimit = -m_normal1; m_upperLimit = -m_normal0; } } else { m_front = offset0 >= 0.0f && offset1 >= 0.0f && offset2 >= 0.0f; if (m_front) { m_normal = m_normal1; m_lowerLimit = m_normal1; m_upperLimit = m_normal1; } else { m_normal = -m_normal1; m_lowerLimit = -m_normal2; m_upperLimit = -m_normal0; } } } else if (hasVertex0) { if (convex1) { m_front = offset0 >= 0.0f || offset1 >= 0.0f; if (m_front) { m_normal = m_normal1; m_lowerLimit = m_normal0; m_upperLimit = -m_normal1; } else { m_normal = -m_normal1; m_lowerLimit = m_normal1; m_upperLimit = -m_normal1; } } else { m_front = offset0 >= 0.0f && offset1 >= 0.0f; if (m_front) { m_normal = m_normal1; m_lowerLimit = m_normal1; m_upperLimit = -m_normal1; } else { m_normal = -m_normal1; m_lowerLimit = m_normal1; m_upperLimit = -m_normal0; } } } else if (hasVertex3) { if (convex2) { m_front = offset1 >= 0.0f || offset2 >= 0.0f; if (m_front) { m_normal = m_normal1; m_lowerLimit = -m_normal1; m_upperLimit = m_normal2; } else { m_normal = -m_normal1; m_lowerLimit = -m_normal1; m_upperLimit = m_normal1; } } else { m_front = offset1 >= 0.0f && offset2 >= 0.0f; if (m_front) { m_normal = m_normal1; m_lowerLimit = -m_normal1; m_upperLimit = m_normal1; } else { m_normal = -m_normal1; m_lowerLimit = -m_normal2; m_upperLimit = m_normal1; } } } else { m_front = offset1 >= 0.0f; if (m_front) { m_normal = m_normal1; m_lowerLimit = -m_normal1; m_upperLimit = -m_normal1; } else { m_normal = -m_normal1; m_lowerLimit = m_normal1; m_upperLimit = m_normal1; } } // Get polygonB in frameA m_polygonB.count = polygonB.VertexCount; for (int i = 0; i < polygonB.VertexCount; ++i) { m_polygonB.vertices[i] = b2Math.b2Mul(ref m_xf, ref polygonB.Vertices[i]); m_polygonB.normals[i] = b2Math.b2Mul(ref m_xf.q, ref polygonB.Normals[i]); } m_radius = 2.0f * b2Settings.b2_polygonRadius; manifold.pointCount = 0; b2EPAxis edgeAxis = ComputeEdgeSeparation(); // Console.WriteLine("b2EPAxis: {0} {1} {2}", edgeAxis.index, edgeAxis.separation, edgeAxis.type); // If no valid normal can be found than this edge should not collide. if (edgeAxis.type == b2EPAxisType.e_unknown) { return; } if (edgeAxis.separation > m_radius) { return; } b2EPAxis polygonAxis = ComputePolygonSeparation(); if (polygonAxis.type != b2EPAxisType.e_unknown && polygonAxis.separation > m_radius) { return; } // Use hysteresis for jitter reduction. const float k_relativeTol = 0.98f; const float k_absoluteTol = 0.001f; b2EPAxis primaryAxis; if (polygonAxis.type == b2EPAxisType.e_unknown) { primaryAxis = edgeAxis; } else if (polygonAxis.separation > k_relativeTol * edgeAxis.separation + k_absoluteTol) { primaryAxis = polygonAxis; } else { primaryAxis = edgeAxis; } //Cached b2ClipVertex[] ie = new b2ClipVertex[2]; b2ClipVertex[] ie = _ie; b2ReferenceFace rf; if (primaryAxis.type == b2EPAxisType.e_edgeA) { manifold.type = b2ManifoldType.e_faceA; // Search for the polygon normal that is most anti-parallel to the edge normal. int bestIndex = 0; float bestValue = b2Math.b2Dot(ref m_normal, ref m_polygonB.normals[0]); for (int i = 1; i < m_polygonB.count; ++i) { float value = b2Math.b2Dot(ref m_normal, ref m_polygonB.normals[i]); if (value < bestValue) { bestValue = value; bestIndex = i; } } int i1 = bestIndex; int i2 = i1 + 1 < m_polygonB.count ? i1 + 1 : 0; ie[0].v = m_polygonB.vertices[i1]; ie[0].id.indexA = 0; ie[0].id.indexB = (byte)i1; ie[0].id.typeA = b2ContactFeatureType.e_face; ie[0].id.typeB = b2ContactFeatureType.e_vertex; ie[1].v = m_polygonB.vertices[i2]; ie[1].id.indexA = 0; ie[1].id.indexB = (byte)i2; ie[1].id.typeA = b2ContactFeatureType.e_face; ie[1].id.typeB = b2ContactFeatureType.e_vertex; if (m_front) { rf.i1 = 0; rf.i2 = 1; rf.v1 = m_v1; rf.v2 = m_v2; rf.normal = m_normal1; } else { rf.i1 = 1; rf.i2 = 0; rf.v1 = m_v2; rf.v2 = m_v1; rf.normal = -m_normal1; } } else { manifold.type = b2ManifoldType.e_faceB; ie[0].v = m_v1; ie[0].id.indexA = 0; ie[0].id.indexB = (byte)primaryAxis.index; ie[0].id.typeA = b2ContactFeatureType.e_vertex; ie[0].id.typeB = b2ContactFeatureType.e_face; ie[1].v = m_v2; ie[1].id.indexA = 0; ie[1].id.indexB = (byte)primaryAxis.index; ie[1].id.typeA = b2ContactFeatureType.e_vertex; ie[1].id.typeB = b2ContactFeatureType.e_face; rf.i1 = primaryAxis.index; rf.i2 = rf.i1 + 1 < m_polygonB.count ? rf.i1 + 1 : 0; rf.v1 = m_polygonB.vertices[rf.i1]; rf.v2 = m_polygonB.vertices[rf.i2]; rf.normal = m_polygonB.normals[rf.i1]; } rf.sideNormal1 = new b2Vec2(rf.normal.y, -rf.normal.x); rf.sideNormal2 = -rf.sideNormal1; rf.sideOffset1 = b2Math.b2Dot(ref rf.sideNormal1, ref rf.v1); rf.sideOffset2 = b2Math.b2Dot(ref rf.sideNormal2, ref rf.v2); // Clip incident edge against extruded edge1 side edges. //Cached b2ClipVertex[] clipPoints1 = new b2ClipVertex[2]; //Cached b2ClipVertex[] clipPoints2 = new b2ClipVertex[2]; b2ClipVertex[] clipPoints1 = _clipPoints1; b2ClipVertex[] clipPoints2 = _clipPoints2; int np; // Clip to box side 1 np = b2Collision.b2ClipSegmentToLine(clipPoints1, ie, ref rf.sideNormal1, rf.sideOffset1, (byte)rf.i1); if (np < b2Settings.b2_maxManifoldPoints) { return; } // Clip to negative box side 1 np = b2Collision.b2ClipSegmentToLine(clipPoints2, clipPoints1, ref rf.sideNormal2, rf.sideOffset2, (byte)rf.i2); if (np < b2Settings.b2_maxManifoldPoints) { return; } // Now clipPoints2 contains the clipped points. if (primaryAxis.type == b2EPAxisType.e_edgeA) { manifold.localNormal = rf.normal; manifold.localPoint = rf.v1; } else { manifold.localNormal = polygonB.Normals[rf.i1]; manifold.localPoint = polygonB.Vertices[rf.i1]; } int pointCount = 0; for (int i = 0; i < b2Settings.b2_maxManifoldPoints; ++i) { float separation; separation = b2Math.b2Dot(rf.normal, clipPoints2[i].v - rf.v1); if (separation <= m_radius) { b2ManifoldPoint cp = manifold.points[pointCount]; if (primaryAxis.type == b2EPAxisType.e_edgeA) { cp.localPoint = b2Math.b2MulT(ref m_xf, ref clipPoints2[i].v); cp.id = clipPoints2[i].id; } else { cp.localPoint = clipPoints2[i].v; cp.id.typeA = clipPoints2[i].id.typeB; cp.id.typeB = clipPoints2[i].id.typeA; cp.id.indexA = clipPoints2[i].id.indexB; cp.id.indexB = clipPoints2[i].id.indexA; } ++pointCount; } } manifold.pointCount = pointCount; }
public b2ManifoldPoint[] CopyPoints() { b2ManifoldPoint[] copy = new b2ManifoldPoint[points.Length]; points.CopyTo(copy, 0); return (copy); }
public static void b2CollidePolygons(b2Manifold manifold, b2PolygonShape polyA, ref b2Transform xfA, b2PolygonShape polyB, ref b2Transform xfB) { manifold.pointCount = 0; float totalRadius = polyA.Radius + polyB.Radius; int edgeA = 0; float separationA = b2FindMaxSeparation(out edgeA, polyA, ref xfA, polyB, ref xfB); if (separationA > totalRadius) { return; } int edgeB = 0; float separationB = b2FindMaxSeparation(out edgeB, polyB, ref xfB, polyA, ref xfA); if (separationB > totalRadius) { return; } b2PolygonShape poly1; // reference polygon b2PolygonShape poly2; // incident polygon b2Transform xf1, xf2; int edge1; // reference edge byte flip; const float k_relativeTol = 0.98f; const float k_absoluteTol = 0.001f; if (separationB > k_relativeTol * separationA + k_absoluteTol) { poly1 = polyB; poly2 = polyA; xf1 = xfB; xf2 = xfA; edge1 = edgeB; manifold.type = b2ManifoldType.e_faceB; flip = 1; } else { poly1 = polyA; poly2 = polyB; xf1 = xfA; xf2 = xfB; edge1 = edgeA; manifold.type = b2ManifoldType.e_faceA; flip = 0; } b2ClipVertex[] incidentEdge = _incidentEdge; b2FindIncidentEdge(incidentEdge, poly1, ref xf1, edge1, poly2, ref xf2); int count1 = poly1.VertexCount; b2Vec2[] vertices1 = poly1.Vertices; int iv1 = edge1; int iv2 = edge1 + 1 < count1 ? edge1 + 1 : 0; b2Vec2 v11 = vertices1[iv1]; b2Vec2 v12 = vertices1[iv2]; b2Vec2 localTangent; localTangent.x = v12.x - v11.x; localTangent.y = v12.y - v11.y; localTangent.Normalize(); b2Vec2 localNormal; localNormal.x = localTangent.y; //.UnitCross(); // b2Math.b2Cross(localTangent, 1.0f); localNormal.y = -localTangent.x; b2Vec2 planePoint; planePoint.x = 0.5f * (v11.x + v12.x); planePoint.y = 0.5f * (v11.y + v12.y); b2Vec2 tangent; tangent.x = xf1.q.c * localTangent.x - xf1.q.s * localTangent.y; tangent.y = xf1.q.s * localTangent.x + xf1.q.c * localTangent.y; float normalx = tangent.y; //UnitCross(); // b2Math.b2Cross(tangent, 1.0f); float normaly = -tangent.x; float v11x = (xf1.q.c * v11.x - xf1.q.s * v11.y) + xf1.p.x; float v11y = (xf1.q.s * v11.x + xf1.q.c * v11.y) + xf1.p.y; float v12x = (xf1.q.c * v12.x - xf1.q.s * v12.y) + xf1.p.x; float v12y = (xf1.q.s * v12.x + xf1.q.c * v12.y) + xf1.p.y; // Face offset. float frontOffset = normalx * v11x + normaly * v11y; // Side offsets, extended by polytope skin thickness. float sideOffset1 = -(tangent.x * v11x + tangent.y * v11y) + totalRadius; float sideOffset2 = tangent.x * v12x + tangent.y * v12y + totalRadius; // Clip incident edge against extruded edge1 side edges. b2ClipVertex[] clipPoints1 = _clipPoints1; int np; // Clip to box side 1 b2Vec2 t; t.x = -tangent.x; t.y = -tangent.y; np = b2ClipSegmentToLine(clipPoints1, incidentEdge, ref t, sideOffset1, (byte)iv1); if (np < 2) { return; } b2ClipVertex[] clipPoints2 = _clipPoints2; // Clip to negative box side 1 np = b2ClipSegmentToLine(clipPoints2, clipPoints1, ref tangent, sideOffset2, (byte)iv2); if (np < 2) { return; } // Now clipPoints2 contains the clipped points. manifold.localNormal = localNormal; manifold.localPoint = planePoint; int pointCount = 0; for (int i = 0; i < b2Settings.b2_maxManifoldPoints; ++i) { var v = clipPoints2[i].v; //float separation = b2Math.b2Dot(ref normal, ref v) - frontOffset; float separation = normalx * v.x + normaly * v.y - frontOffset; if (separation <= totalRadius) { b2ManifoldPoint cp = manifold.points[pointCount]; //cp.localPoint = b2Math.b2MulT(ref xf2, ref v); float px = v.x - xf2.p.x; float py = v.y - xf2.p.y; cp.localPoint.x = (xf2.q.c * px + xf2.q.s * py); cp.localPoint.y = (-xf2.q.s * px + xf2.q.c * py); cp.id = clipPoints2[i].id; if (flip != 0) { // Swap features b2ContactFeature cf = cp.id; cp.id.indexA = cf.indexB; cp.id.indexB = cf.indexA; cp.id.typeA = cf.typeB; cp.id.typeB = cf.typeA; } ++pointCount; } } manifold.pointCount = pointCount; }
// The normal points from 1 to 2 static public void CollidePolygons(b2Manifold manifold, b2PolygonShape polyA, b2Transform xfA, b2PolygonShape polyB, b2Transform xfB) { ClipVertex cv; manifold.m_pointCount = 0; float totalRadius = polyA.m_radius + polyB.m_radius; int edgeA = 0; s_edgeAO[0] = edgeA; float separationA = FindMaxSeparation(s_edgeAO, polyA, xfA, polyB, xfB); edgeA = s_edgeAO[0]; if (separationA > totalRadius) { return; } int edgeB = 0; s_edgeBO[0] = edgeB; float separationB = FindMaxSeparation(s_edgeBO, polyB, xfB, polyA, xfA); edgeB = s_edgeBO[0]; if (separationB > totalRadius) { return; } b2PolygonShape poly1; // reference poly b2PolygonShape poly2; // incident poly b2Transform xf1; b2Transform xf2; int edge1; // reference edge uint flip; const float k_relativeTol = 0.98f; const float k_absoluteTol = 0.001f; b2Mat22 tMat; if (separationB > k_relativeTol * separationA + k_absoluteTol) { poly1 = polyB; poly2 = polyA; xf1 = xfB; xf2 = xfA; edge1 = edgeB; manifold.m_type = b2Manifold.e_faceB; flip = 1; } else { poly1 = polyA; poly2 = polyB; xf1 = xfA; xf2 = xfB; edge1 = edgeA; manifold.m_type = b2Manifold.e_faceA; flip = 0; } ClipVertex[] incidentEdge = s_incidentEdge; FindIncidentEdge(incidentEdge, poly1, xf1, edge1, poly2, xf2); int count1 = poly1.m_vertexCount; List <b2Vec2> vertices1 = poly1.m_vertices; b2Vec2 local_v11 = vertices1[edge1]; b2Vec2 local_v12; if (edge1 + 1 < count1) { local_v12 = vertices1[(int)(edge1 + 1)]; } else { local_v12 = vertices1[0]; } b2Vec2 localTangent = s_localTangent; localTangent.Set(local_v12.x - local_v11.x, local_v12.y - local_v11.y); localTangent.Normalize(); b2Vec2 localNormal = s_localNormal; localNormal.x = localTangent.y; localNormal.y = -localTangent.x; b2Vec2 planePoint = s_planePoint; planePoint.Set(0.5f * (local_v11.x + local_v12.x), 0.5f * (local_v11.y + local_v12.y)); b2Vec2 tangent = s_tangent; //tangent = b2Math.b2MulMV(xf1.R, localTangent); tMat = xf1.R; tangent.x = (tMat.col1.x * localTangent.x + tMat.col2.x * localTangent.y); tangent.y = (tMat.col1.y * localTangent.x + tMat.col2.y * localTangent.y); b2Vec2 tangent2 = s_tangent2; tangent2.x = -tangent.x; tangent2.y = -tangent.y; b2Vec2 normal = s_normal; normal.x = tangent.y; normal.y = -tangent.x; //v11 = b2Math.MulX(xf1, local_v11); //v12 = b2Math.MulX(xf1, local_v12); b2Vec2 v11 = s_v11; b2Vec2 v12 = s_v12; v11.x = xf1.position.x + (tMat.col1.x * local_v11.x + tMat.col2.x * local_v11.y); v11.y = xf1.position.y + (tMat.col1.y * local_v11.x + tMat.col2.y * local_v11.y); v12.x = xf1.position.x + (tMat.col1.x * local_v12.x + tMat.col2.x * local_v12.y); v12.y = xf1.position.y + (tMat.col1.y * local_v12.x + tMat.col2.y * local_v12.y); // Face offset float frontOffset = normal.x * v11.x + normal.y * v11.y; // Side offsets, extended by polytope skin thickness float sideOffset1 = -tangent.x * v11.x - tangent.y * v11.y + totalRadius; float sideOffset2 = tangent.x * v12.x + tangent.y * v12.y + totalRadius; // Clip incident edge against extruded edge1 side edges. ClipVertex[] clipPoints1 = s_clipPoints1; ClipVertex[] clipPoints2 = s_clipPoints2; int np; // Clip to box side 1 //np = ClipSegmentToLine(clipPoints1, incidentEdge, -tangent, sideOffset1); np = ClipSegmentToLine(clipPoints1, incidentEdge, tangent2, sideOffset1); if (np < 2) { return; } // Clip to negative box side 1 np = ClipSegmentToLine(clipPoints2, clipPoints1, tangent, sideOffset2); if (np < 2) { return; } // Now clipPoints2 contains the clipped points. manifold.m_localPlaneNormal.SetV(localNormal); manifold.m_localPoint.SetV(planePoint); int pointCount = 0; for (int i = 0; i < b2Settings.b2_maxManifoldPoints; ++i) { cv = clipPoints2[i]; float separation = normal.x * cv.v.x + normal.y * cv.v.y - frontOffset; if (separation <= totalRadius) { b2ManifoldPoint cp = manifold.m_points[pointCount]; //cp.m_localPoint = b2Math.b2MulXT(xf2, cv.v); tMat = xf2.R; float tX = cv.v.x - xf2.position.x; float tY = cv.v.y - xf2.position.y; cp.m_localPoint.x = (tX * tMat.col1.x + tY * tMat.col1.y); cp.m_localPoint.y = (tX * tMat.col2.x + tY * tMat.col2.y); cp.m_id.Set(cv.id); cp.m_id.features.flip = (int)flip; ++pointCount; } } manifold.m_pointCount = pointCount; }