[Indigo]<CedarHacks5.2>BiScrollers>Geom2D.Mesa!1

Geom2D.Mesa, from [Ivy]<Spreitzer>Random>Cedar>Geom2D.DF

Last Edited by: Spreitzer, April 16, 1983 1:11 pm

some two dimensional geometry

DIRECTORY

Graphics;

Geom2D: CEDAR DEFINITIONS =

BEGIN

Singularity: SIGNAL;

Number: TYPE = REAL;

Vec: TYPE = RECORD [x, y: Number];

VecList: TYPE = LIST OF Vec;

ZeroVec: Vec = [0, 0];

Line: TYPE = RECORD [from, to: Vec]; --directed line segment

Area: TYPE = Graphics.Box;

AreaList: TYPE = LIST OF Area;

ZeroArea: Area = [0, 0, 0, 0];

Axis: TYPE = {X, Y};

Dir: TYPE = [-1..1];

Direction: TYPE = RECORD [axis: Axis, sgn: Dir];

Transform: TYPE = RECORD [a, b, c, d, e, f: Number];

a b 0

c d 0

e f 1

id: Transform = [1, 0, 0, 1, 0, 0];

posX: Direction = [X, 1];

negX: Direction = [X, -1];

posY: Direction = [Y, 1];

negY: Direction = [Y, -1];

Plus, Minus, Project: PROCEDURE [Vec, Vec] RETURNS [Vec];

Normalize: PROCEDURE [Vec] RETURNS [Vec];

Displace: PROCEDURE [Vec, Area] RETURNS [Area];

Scale: PROCEDURE [Vec, Number] RETURNS [Vec];

Dot: PROCEDURE [Vec, Vec] RETURNS [Number];

Length: PROCEDURE [Vec] RETURNS [Number];

DirectionOf: PROCEDURE [Vec] RETURNS [Direction];

BloatLine: PROCEDURE [Line, Number] RETURNS [Area];

BloatVec: PROCEDURE [Vec, Number] RETURNS [Area];

UnitNormalToward: PROCEDURE [Line, Vec] RETURNS [Vec];

In: PROCEDURE [Vec, Area] RETURNS [BOOLEAN];

SweepBounds: PROCEDURE [Area, Area] RETURNS [Area];

UpdateBounds: PROCEDURE [Area, Area] RETURNS [Area]; --mbb of both--

UpdateFBounds: PROCEDURE [Area, FBounds] RETURNS [FBounds];

Parallel: PROCEDURE [Vec, Vec] RETURNS [BOOLEAN]; --cross product = 0

Translate: PROCEDURE [Transform, Number, Number] RETURNS [Transform];

TranslateV: PROCEDURE [Transform, Vec] RETURNS [Transform];

ScaleT: PROCEDURE [Transform, Number] RETURNS [Transform];

ScaleTXY: PROCEDURE [Transform, Number, Number] RETURNS [Transform];

RotateBy90s: PROCEDURE [Transform, INTEGER] RETURNS [Transform];

counterclockwise

RotateDegrees: PROCEDURE [Transform, Number--degrees--] RETURNS [Transform];

Inverse: PROCEDURE [Transform] RETURNS [Transform];

MapVec: PROCEDURE [Transform, Vec] RETURNS [Vec];

MapVecs: PROCEDURE [Transform, VecList] RETURNS [VecList];

MapArea: PROCEDURE [Transform, Area] RETURNS [Area];

MapAreas: PROCEDURE [Transform, AreaList] RETURNS [AreaList];

Concat: PROCEDURE [Transform, Transform] RETURNS [Transform];

ExtremaRec: TYPE = RECORD [minD, maxD: Number, minV, maxV: Vec];

StartExtreme: PROCEDURE [n, v: Vec] RETURNS [ExtremaRec] = INLINE

{d: Number ← Dot[n, v];

RETURN [[d, d, v, v]]};

Extreme: PROCEDURE [n, v: Vec, e: ExtremaRec]

RETURNS [ExtremaRec] = INLINE

{d: Number ← Dot[n, v];

IF d < e.minD THEN RETURN [[d, e.maxD, v, e.maxV]]

ELSE IF d > e.maxD THEN RETURN [[e.minD, d, e.minV, v]]

ELSE RETURN [e]};

ExtremaOfBounds: PROCEDURE [a: Area, n: Vec] RETURNS [min, max: Vec] = INLINE

{e: ExtremaRec ← n.Extreme[[a.xmin, a.ymin],

n.Extreme[[a.xmin, a.ymax],

n.Extreme[[a.xmax, a.ymin],

n.StartExtreme[[a.xmax, a.ymax]]]]];

RETURN [e.minV, e.maxV]};

FBounds: TYPE = RECORD [defined: BOOLEAN ← FALSE,

area: Area ← ZeroArea];

END.