Copyright (C) 1994, Digital Equipment Corporation                         
 Digital Internal Use Only                                                 
 All rights reserved.                                                      
 Last modified on Fri Jul 14 17:20:02 PDT 1995 by najork                   
       Created on Wed Feb 16 17:57:52 PST 1994 by najork                   

INTERFACE GraphicsBasePrivate;

IMPORT BSphere, Color, GO, LineTypeProp, MarkerTypeProp, Matrix4, Point,
       Point3, PropPrivate, ProxiedObj, RasterModeProp, RootGO, ShadingProp;

FROM GraphicsBase IMPORT T;

  VoidColor = Color.T {-1.0, -1.0, -1.0};

REVEAL T <: Private;

  Private = ProxiedObj.T BRANDED OBJECT
    root   : RootGO.T := NIL;
    status : Status   := Status.Unmapped;
    stacks : REF ARRAY OF PropPrivate.Stack;
    unmap ();
    processEvents ();
    repair (VAR damaged : BOOLEAN);

    (*** Pushing and popping property lists onto the state **)
    push (caller : GO.T);
    pop (caller : GO.T);

    (*** Display Lists ***)
    openDisplayList (go : GO.T);
    closeDisplayList ();
    callDisplayList (go : GO.T);
    freeDisplayList (go : GO.T);

    (*** The matrix stack ***)
    pushMatrix (READONLY matrix : Matrix4.T);
    popMatrix ();

    (* Bounding volumes *)
    resetBoundingVolume ();
    growBoundingVolume (center : Point3.T; radius : REAL);
    getBoundingVolume () : BSphere.T;

    (* Camera control - setting viewing and projection transformations, and
       mapping points from screen coordinate space to world coordinate space *)
    setLookAt (from, to, up: Point3.T);
    setPerspProj (fovy, aspect: REAL);
    setOrthoProj (height, aspect: REAL);
    setupCamera ();
    screenToWorld (pos: Point.T; z: REAL): Point3.T;

    (*** Graphics Commands ***)
    setBackgroundColor (color : Color.T);
    setDepthcueing (switch: BOOLEAN;
                    frontPlane, backPlane, frontScale, backScale: REAL;
                    color: Color.T);

    setMarkerColor (val : Color.T);
    setMarkerScale (val : REAL);
    setMarkerType  (val : MarkerTypeProp.Kind);

    setLineColor (val : Color.T);
    setLineWidth (val : REAL);
    setLineType  (val : LineTypeProp.Kind);

    setSurfaceColor (val : Color.T);
    setSurfaceBackColor (val : Color.T);
       (* setting the back color to "VoidColor" indicates that it shall
          be the same as the front color *)
    setRasterMode (val : RasterModeProp.Kind);
    setDistinguishFacetsFlag (val : BOOLEAN);
    setLighting (val : BOOLEAN);
    setShading (val : ShadingProp.Kind);
    setSurfaceEdgeFlag (val : BOOLEAN);
    setSurfaceEdgeColor (val : Color.T);
    setSurfaceEdgeType (val : LineTypeProp.Kind);
    setSurfaceEdgeWidth (val : REAL);

    setAmbientReflCoeff (val : REAL);
    setDiffuseReflCoeff (val : REAL);
    setSpecularReflCoeff (val : REAL);
    setSpecularReflConc (val : REAL);
    setSpecularReflColor (val : Color.T);
    setTransmissionCoeff (val : REAL);

    addAmbientLight (color: Color.T);
    addVectorLight  (color: Color.T; dir: Point3.T);
    addPointLight (color: Color.T; point: Point3.T; att0, att1: REAL);
    addSpotLight (color: Color.T; point, dir: Point3.T;
                  conc, spread, att0, att1: REAL);

    drawMarker (p : Point3.T);
    drawLine (p1, p2 : Point3.T);
    drawPolygon (READONLY pts : ARRAY OF Point3.T; shape : GO.Shape);
    drawQuadMesh (READONLY pts : ARRAY OF ARRAY OF Point3.T; shape : GO.Shape);
    drawColoredQuadMesh (READONLY points: ARRAY OF ARRAY OF Point3.T;
                         READONLY colors: ARRAY OF ARRAY OF Color.T;
                                  shape : GO.Shape);

    drawProtoSphere (prec : INTEGER);
    drawProtoCone (prec : INTEGER);
    drawProtoCylinder (prec : INTEGER);
    drawProtoDisk (prec : INTEGER);
    drawProtoTorus (prec: INTEGER; radiusRatio : REAL);
  END; redraws the scene rooted at base.root. Only those nodes that were marked as damaged are re-rendered, for the other nodes, cached values are used.

Nodes can be damaged in two ways: \begin{enumerate} \item By operations that change the scene DAG (i.e.\ the group operations add, remove, and flush). \item By changes in the value of an attached property. \end{enumerate}

Calling root.adjust(time) serves two purposes: It reevaluates all the properties attached to all descendants of root, and damages those nodes whose properties have changed since the last round of rendering. It also propagates damages up the scene DAGs. is called after all roots have been adjusted. The VAR parameter damaged is set to TRUE if there were any damages in the scene, otherwise, it remains unchanged.

TYPE Status = {Unmapped, Mapped, Destroyed};

END GraphicsBasePrivate.