initial checkin of C++ port (in progress)

git-svn-id: svn://svn.code.sf.net/p/magicseteditor/code/trunk@2 0fc631ac-6414-0410-93d0-97cfa31319b6

src/gfx/bezier.hpp

@@ -0,0 +1,130 @@
+//+----------------------------------------------------------------------------+
+//| Description:  Magic Set Editor - Program to make Magic (tm) cards          |
+//| Copyright:    (C) 2001 - 2006 Twan van Laarhoven                           |
+//| License:      GNU General Public License 2 or later (see file COPYING)     |
+//+----------------------------------------------------------------------------+
+
+#ifndef HEADER_GFX_BEZIER
+#define HEADER_GFX_BEZIER
+
+/** @file gfx/bezier.hpp
+ *
+ *  Bezier curve and line related functions
+ */
+
+// ----------------------------------------------------------------------------- : Includes
+
+#include <util/prec.hpp>
+#include <util/rotation.hpp>
+#include <data/symbol.hpp>
+
+// ----------------------------------------------------------------------------- : Evaluation
+
+/// A bezier curve for evaluation
+class BezierCurve {
+  public:
+	/// coefficients of the equation (x,y) = at^3 + bt^2 + ct + d
+	Vector2D a, b, c, d;
+	
+	/// Construct a bezier curve evaluator given the 4 handles
+	BezierCurve(const Vector2D& p0, const Vector2D& p1, const Vector2D& p2, const Vector2D& p3);
+	
+	/// Construct a bezier curve evaluator given two ControlPoints at the ends
+	BezierCurve(const ControlPoint& p0, const ControlPoint& p3);
+	
+	/// Return the point on this curve at time t in [0...1)
+	inline Vector2D pointAt(double t) const {
+		return d + (c + (b + a * t) * t) * t;
+	}
+	
+	/// Return the tangent on this curve at time t in [0...1)	
+	inline Vector2D tangentAt(double t) const {
+		return c + ((b * 2) + (a * 3) * t) * t;
+	}
+};
+
+/// Subdivide a curve from a to b, store the result in a control point
+/** Also modifies the handles of the points to accomodate the inserted point
+ *  Direct version, using input curve a1,a2,a3,a4 and output curves a1,b2,b3,b4 and c1,c2,c3,a4
+ */
+void deCasteljau(Vector2D a1,  Vector2D  a2, Vector2D  a3, Vector2D  a4,
+                 Vector2D& b2, Vector2D& b3, Vector2D& b4c1,
+                 Vector2D& c2, Vector2D& c3, double t);
+
+/// Subdivide a curve from a to b at time t
+/** Stores the point at time t in mid, updates the handles of a and b!
+ */
+void deCasteljau(ControlPoint& a, ControlPoint& b, double t, ControlPoint& mid);
+
+/// Subdivide a curve from a to b, store the result in a control point
+/** Also modifies the handles of the points to accomodate the inserted point!
+ */
+void deCasteljau(const Vector2D& a1, Vector2D& a21, Vector2D& a34, const Vector2D& a4, double t, ControlPoint& out);
+
+// ----------------------------------------------------------------------------- : Drawing
+
+/// Devide a segment into a number of straight lines for display purposes
+/** Adds the resulting corner points of those lines to out, the last point is not added.
+ *  All points are converted to display coordinates using rot.tr
+ */
+void segmentSubdivide(const ControlPoint& p0, const ControlPoint& p1, const Rotation& rot, vector<wxPoint>& out);
+
+// ----------------------------------------------------------------------------- : Bounds
+
+/// Find a bounding box that fits a segment (either a line or a bezier curve) between p1 and p2.
+/** stores the results in min and max.
+ *  min is only changed if the minimum is smaller then the current value in min,
+ *  max only if the maximum is larger.
+ */
+void segmentBounds(const ControlPoint& p1, const ControlPoint& p2, Vector2D& min, Vector2D& max);
+
+/// Find a bounding box that fits a curve between p1 and p2, stores the results in min and max.
+/** min is only changed if the minimum is smaller then the current value in min,
+ *  max only if the maximum is larger
+ */
+void bezierBounds(const ControlPoint& p1, const ControlPoint& p2, Vector2D& min, Vector2D& max);
+
+/// Find a bounding box that fits around p1 and p2, stores the result in min and max
+/** min is only changed if the minimum is smaller then the current value in min,
+ *  max only if the maximum is larger
+ */
+void lineBounds(const Vector2D& p1, const Vector2D& p2, Vector2D& min, Vector2D& max);
+
+/// Find a bounding 'box' that fits around a single point
+/** min is only changed if the minimum is smaller then the current value in min,
+ *  max only if the maximum is larger
+ */
+void pointBounds(const Vector2D& p, Vector2D& min, Vector2D& max);
+
+// ----------------------------------------------------------------------------- : Point tests
+
+/// Is a point inside the given symbol part?
+bool pointInPart(const Vector2D& p, const SymbolPart& part);
+
+// ----------------------------------------------------------------------------- : Finding points
+
+/// Finds the position of p0 on the line between p1 and p2, returns true if the point is on (or near) the line
+/// the line between p1 and p2 can also be a bezier curve
+/** Returns the time on the segment in tOut, and the point on the segment in pOut
+ */
+bool posOnSegment(const Vector2D& pos, double range, const ControlPoint& p1, const ControlPoint& p2, Vector2D& pOut, double& tOut);
+
+/// Finds the position of p0 on the line between p1 and p2, returns true if the point is on (or near)
+/// the bezier curve between p1 and p2
+bool posOnBezier (const Vector2D& pos, double range, const ControlPoint& p1, const ControlPoint& p2, Vector2D& pOut, double& tOut);
+
+/// Finds the position of p0 on the line p1-p2, returns true if the point is withing range of the line
+/// if that is the case then (x,y) = p1 + (p2-p1) * out
+bool posOnLine   (const Vector2D& pos, double range, const Vector2D& p1,     const Vector2D& p2,     Vector2D& pOut, double& tOut);
+
+// ----------------------------------------------------------------------------- : Intersection
+
+/// Counts the number of intersections between the ray/halfline from (-inf, pos.y) to pos
+/// and the bezier curve between p1 and p2.
+UInt intersectBezierRay(const ControlPoint& p1, const ControlPoint& p2, const Vector2D& pos);
+
+// Does the line between p1 and p2 intersect the ray (half line) from (-inf, pos.y) to pos?
+bool intersectLineRay(const Vector2D& p1, const Vector2D& p2, const Vector2D& pos);
+
+// ----------------------------------------------------------------------------- : EOF
+#endif