DIRECTORY SV2d; SVLines2d: CEDAR DEFINITIONS = BEGIN LineSeg: TYPE = REF LineSegObj; LineSegObj: TYPE = SV2d.LineSegObj; Point2d: TYPE = SV2d.Point2d; Ray2d: TYPE = REF Ray2dObj; Ray2dObj: TYPE = SV2d.Ray2dObj; TrigLine: TYPE = REF TrigLineObj; TrigLineObj: TYPE = SV2d.TrigLineObj; TrigLineSeg: TYPE = REF TrigLineSegObj; TrigLineSegObj: TYPE = SV2d.TrigLineSegObj; Vector2d: TYPE = SV2d.Vector2d; CreateEmptyTrigLine: PUBLIC PROC RETURNS [line: TrigLine]; CopyTrigLine: PROC [from: TrigLine, to: TrigLine]; FillTrigLineFromPoints: PROC [v1, v2: Point2d, line: TrigLine]; FillTrigLineFromPointAndVector: PROC [pt: Point2d, vec: Vector2d, line: TrigLine]; FillTrigLineFromCoefficients: PROC [sineOfTheta, cosineOfTheta, distance: REAL, line: TrigLine]; FillTrigLineAsNormal: PROC [line: TrigLine, pt: Point2d, normalLine: TrigLine]; TrigLineFromPoints: PROC [v1, v2: Point2d] RETURNS [line: TrigLine]; TrigLineFromPointAndVector: PROC [pt: Point2d, vec: Vector2d] RETURNS [line: TrigLine]; TrigLineFromCoefficients: PROC [sineOfTheta, cosineOfTheta, distance: REAL] RETURNS [line: TrigLine]; TrigLineNormalToTrigLineThruPoint: PROC [line: TrigLine, pt: Point2d] RETURNS [normalLine: TrigLine]; TrigLineMeetsTrigLine: PROC [line1, line2: TrigLine] RETURNS [intersection: Point2d, parallel: BOOL]; TrigLineMeetsYAxis: PROC [line: TrigLine] RETURNS [yInt: REAL, parallel: BOOL]; TrigLineMeetsTrigLineSeg: PROC [line: TrigLine, seg: TrigLineSeg] RETURNS [intersection: Point2d, noHit: BOOL]; TrigLineDistance: PROC [pt: Point2d, line: TrigLine] RETURNS [d: REAL]; PointProjectedOntoTrigLine: PROC [pt: Point2d, line: TrigLine] RETURNS [projectedPt: Point2d]; CreateTrigLineSeg: PROC [v1, v2: Point2d] RETURNS [seg: TrigLineSeg]; CreateEmptyTrigLineSeg: PROC RETURNS [seg: TrigLineSeg]; FillTrigLineSeg: PROC [v1, v2: Point2d, seg: TrigLineSeg]; CopyTrigLineSeg: PROC [from: TrigLineSeg, to: TrigLineSeg]; TrigLinePointOnTrigLineSeg: PROC [pt: Point2d, seg: TrigLineSeg] RETURNS [BOOL]; NearestEndpoint: PROC [pt: Point2d, seg: TrigLineSeg] RETURNS [endpoint: Point2d]; DistanceSquaredToNearestEndpoint: PUBLIC PROC [pt: Point2d, seg: TrigLineSeg] RETURNS [distanceSquared: REAL]; DistancePointToTrigLineSeg: PROC [pt: Point2d, seg: TrigLineSeg] RETURNS [distance: REAL]; DistanceSquaredPointToTrigLineSeg: PROC [pt: Point2d, seg: TrigLineSeg] RETURNS [distanceSquared: REAL]; DistancePointToPoint: PROC [p1, p2: Point2d] RETURNS [distance: REAL]; DistanceSquaredPointToPoint: PROC [p1, p2: Point2d] RETURNS [distance: REAL]; PointLeftOfTrigLine: PROC [distance: REAL, pOnLine: Point2d, line: TrigLine] RETURNS [point: Point2d]; CreateLineSeg: PROC [v1, v2: Point2d] RETURNS [seg: LineSeg]; CreateRay: PROC [basePoint: Point2d, direction: Vector2d] RETURNS [ray: Ray2d]; CreateRayFromPoints: PROC [p1, p2: Point2d] RETURNS [ray: Ray2d]; RightHorizontalRay: PROC [point: Point2d] RETURNS [horizRayThruPoint: Ray2d]; UpVerticalRay: PROC [point: Point2d] RETURNS [vertRayThruPoint: Ray2d]; RayMeetsBox: PROC [ray: Ray2d, xmin, ymin, xmax, ymax: REAL] RETURNS [count: NAT, params: ARRAY[1..2] OF REAL]; LineRayMeetsBox: PROC [ray: Ray2d, xmin, ymin, xmax, ymax: REAL] RETURNS [count: NAT, params: ARRAY[1..2] OF REAL]; EvalRay: PROC [ray: Ray2d, param: REAL] RETURNS [point: Point2d]; END. ÆFile: SVLines2d.mesa Author: Eric Bier on October 1, 1982 9:02 pm Last edited by Bier on September 4, 1986 3:32:41 pm PDT Contents: Routines for finding the intersections of various types of lines and line segments used in the SolidViews package. TRIGLINES Since trig lines are fairly large data structures, you may prefer to allocate one with CreateEmptyTrigLine and repeatedly fill it with new data instead of allocating a new one each time. This procedures allocate a new TrigLine. We drop a normal from the point onto the line and find where it hits the line equation of the normal we drop can be found as in FillTrigLineAsNormal above. TRIGLINESEGS Assumes pt is on seg.line. Is it on seg? Faster than DistancePointToPoint[pt, NearestEndpoint[pt, seg]] (if you don't care what the endpoint is). Perpendicular distance if possible, else distance to nearest endpoint. POINT2DS point is a point to the left of the directed line, on the normal to the line which intersects the line at pOnLine. 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