File: SVBoundBox.mesa
Last edited by Bier on September 1, 1987 11:25:21 am PDT
Contents: Procedures for creating bounding polyhedra of master objects, and for deriving "3-d" bounding boxes from these polyhedra. Procedures for combining these bounding boxes with union, intersection and difference operators.
DIRECTORY
Imager, SV2d, SV3d, SVBasicTypes, SVModelTypes, SVSceneTypes, SVSelect;
SVBoundBox: CEDAR DEFINITIONS =
BEGIN
BoundHedron: TYPE = SVBasicTypes.BoundHedron;
BoundBox: TYPE = SVBasicTypes.BoundBox;
Camera: TYPE = SVModelTypes.Camera;
CoordSystem: TYPE = SVModelTypes.CoordSystem;
Point2d: TYPE = SV2d.Point2d;
Point3d: TYPE = SV3d.Point3d;
Poly3d: TYPE = SV3d.Poly3d;
Scene: TYPE = SVSceneTypes.Scene;
SelectionClass: TYPE = SVSelect.SelectionClass;
Bounding Polyhedra (BoundHedron for short)
CreateBoundHedron: PROC [len: NAT] RETURNS [bh: BoundHedron];
AddBoundHedronPoint: PROC [bh: BoundHedron, point: Point3d];
AddBoundHedronPoly: PROC [bh: BoundHedron, poly: Poly3d];
RectangularBoundHedron:
PROC [sx, sy, sz:
REAL]
RETURNS [bh: BoundHedron];
Rectangular parallelpiped centered on the origin with dimensions given
RectangularBoundHedron2:
PROC [x1, x2, y1, y2, z1, z2:
REAL]
RETURNS [bh: BoundHedron];
Like RectangularBoundHedron but use limits given instead of centering on origin
PyramidBoundHedron:
PROC [sx, sy, sz:
REAL]
RETURNS [bh: BoundHedron];
A pyramid with base of size sx by sz on the y=0 plane and tip at [0, sy, 0].
HexagonalBoundHedron:
PROC [r, hOver2:
REAL]
RETURNS [bh: BoundHedron];
A vertical hexagonal prism, ie the shape which would be produced by sweeping the hexagon (which circumscribes the circle x^2 + z^2 = r^2) from [0, -h/2, 0] to [0, h/2, 0].
HexPyramidBoundHedron:
PROC [r, h:
REAL]
RETURNS [bh: BoundHedron];
A pyramid having a hexagonal base of inner radius r on the y = 0 plane (centered on [0,0,]) and having tip at [0, h, 0]
GeneralConeBoundHedron:
PROC [r1, h1, r2, h2:
REAL]
RETURNS [bh: BoundHedron];
Bounds a cone slice (cone around y axis) with radius r1 at y=h1 and radius r2 at y = h2. Currently uses two hexagons. Octagons may follow.
DiskBoundHedron:
PROC [r, h:
REAL]
RETURNS [bh: BoundHedron];
Bounds a disk (centered on y axis) with radius r at y = h;
ClearBoundHedron: PROC [bh: BoundHedron];
DrawBoundHedron: PROC [dc: Imager.Context, bh: BoundHedron, localWRTWorld: CoordSystem, camera: Camera, screen: CoordSystem];
CenterOfMassBoundHedron: PROC [bh: BoundHedron] RETURNS [cm: Point3d];
Bounding Boxes (e.g. Three-D blocks)
These blocks tend to have two faces parallel to the screen. Hence, they can be used as two-dimensional bounding boxes by ignoring the z coordinates.
Three Dimensional BoundBox Operations
NullBoundBox: PROC [] RETURNS [bBox: BoundBox];
BoundBoxFromBoundHedron: PROC [bh: BoundHedron, camera: Camera, localCS: CoordSystem] RETURNS [boundBox: BoundBox];
FillBoundBoxFromBoundHedron: PROC [bh: BoundHedron, camera: Camera, localCS: CoordSystem, boundBox: BoundBox];
BoundBoxFromValues: PROC [minX, minY, maxX, maxY: REAL] RETURNS [boundBox: BoundBox];
BoundBoxFromRectangle:
PROC [rect: Imager.Rectangle, camera: Camera]
RETURNS [bBox: BoundBox];
Takes a rectangle in screen coordinates and returns a bound box in Camera coordinates.
UnionCombineBoundBoxes: PROC [bb1, bb2: BoundBox] RETURNS [newBB: BoundBox];
IntersectionCombineBoundBoxes: PROC [bb1, bb2: BoundBox] RETURNS [newBB: BoundBox];
DifferenceCombineBoundBoxes: PROC [bb1, bb2: BoundBox] RETURNS [newBB: BoundBox];
Two Dimensional BoundBox Operations
EnlargeByBox: PROC [bBox: BoundBox, by: BoundBox];
BoundBoxOfMoving: PROC [scene: Scene, camera: Camera] RETURNS [bigBox: BoundBox];
BoundBoxOfSelected: PROC [scene: Scene, camera: Camera, selectClass: SelectionClass] RETURNS [bigBox: BoundBox];
PointInBoundBox: PROC [cameraPoint: Point2d, boundBox: BoundBox] RETURNS [BOOL];
OutsideOf:
PROC [test, bound: BoundBox]
RETURNS [
BOOL];
Returns TRUE if test does not overlap bound at all. Only the x and y coordinates are checked.
DrawBoundBox: PROC [dc: Imager.Context, boundBox: BoundBox, screen: CoordSystem];
EraseWithinBoundBox: PROC [dc: Imager.Context, boundBox: BoundBox, screen: CoordSystem];
Clip: PROC [dc: Imager.Context, bBox: BoundBox, screen: CoordSystem];
END.