Solve() публичный Метод

Solve A * x = b, where b is a column vector. This is more efficient than computing the inverse in one-shot cases.
public Solve ( System.Vector2 b ) : System.Vector2
b System.Vector2
Результат System.Vector2
Документация по классу Mat22
Пример #1
0
		internal PolygonShape(ShapeDef def)
			: base(def)
		{
			Box2DXDebug.Assert(def.Type == ShapeType.PolygonShape);
			_type = ShapeType.PolygonShape;
			PolygonDef poly = (PolygonDef)def;

			// Get the vertices transformed into the body frame.
			_vertexCount = poly.VertexCount;
			Box2DXDebug.Assert(3 <= _vertexCount && _vertexCount <= Settings.MaxPolygonVertices);

			// Copy vertices.
			for (int i = 0; i < _vertexCount; ++i)
			{
				_vertices[i] = poly.Vertices[i];
			}

			// Compute normals. Ensure the edges have non-zero length.
			for (int i = 0; i < _vertexCount; ++i)
			{
				int i1 = i;
				int i2 = i + 1 < _vertexCount ? i + 1 : 0;
				Vec2 edge = _vertices[i2] - _vertices[i1];
				Box2DXDebug.Assert(edge.LengthSquared() > Common.Settings.FLT_EPSILON * Common.Settings.FLT_EPSILON);
				_normals[i] = Vec2.Cross(edge, 1.0f);
				_normals[i].Normalize();
			}

#if DEBUG
			// Ensure the polygon is convex.
			for (int i = 0; i < _vertexCount; ++i)
			{
				for (int j = 0; j < _vertexCount; ++j)
				{
					// Don't check vertices on the current edge.
					if (j == i || j == (i + 1) % _vertexCount)
					{
						continue;
					}

					// Your polygon is non-convex (it has an indentation).
					// Or your polygon is too skinny.
					float s = Vec2.Dot(_normals[i], _vertices[j] - _vertices[i]);
					Box2DXDebug.Assert(s < -Settings.LinearSlop);
				}
			}

			// Ensure the polygon is counter-clockwise.
			for (int i = 1; i < _vertexCount; ++i)
			{
				float cross = Vec2.Cross(_normals[i - 1], _normals[i]);

				// Keep asinf happy.
				cross = Common.Math.Clamp(cross, -1.0f, 1.0f);

				// You have consecutive edges that are almost parallel on your polygon.
				float angle = (float)System.Math.Asin(cross);
				Box2DXDebug.Assert(angle > Settings.AngularSlop);
			}
#endif

			// Compute the polygon centroid.
			_centroid = ComputeCentroid(poly.Vertices, poly.VertexCount);

			// Compute the oriented bounding box.
			ComputeOBB(out _obb, _vertices, _vertexCount);

			// Create core polygon shape by shifting edges inward.
			// Also compute the min/max radius for CCD.
			for (int i = 0; i < _vertexCount; ++i)
			{
				int i1 = i - 1 >= 0 ? i - 1 : _vertexCount - 1;
				int i2 = i;

				Vec2 n1 = _normals[i1];
				Vec2 n2 = _normals[i2];
				Vec2 v = _vertices[i] - _centroid; ;

				Vec2 d = new Vec2();
				d.X = Vec2.Dot(n1, v) - Settings.ToiSlop;
				d.Y = Vec2.Dot(n2, v) - Settings.ToiSlop;

				// Shifting the edge inward by b2_toiSlop should
				// not cause the plane to pass the centroid.

				// Your shape has a radius/extent less than b2_toiSlop.
				Box2DXDebug.Assert(d.X >= 0.0f);
				Box2DXDebug.Assert(d.Y >= 0.0f);
				Mat22 A = new Mat22();
				A.Col1.X = n1.X; A.Col2.X = n1.Y;
				A.Col1.Y = n2.X; A.Col2.Y = n2.Y;
				_coreVertices[i] = A.Solve(d) + _centroid;
			}
		}