anim3D/src/SurfaceGO.i3

 Copyright (C) 1993, Digital Equipment Corporation                         
 All rights reserved.                                                      
 See the file COPYRIGHT for a full description.                            
                                                                           
 Created by Marc Najork                                                    
 Last modified on Fri Feb  3 13:57:57 PST 1995 by najork                   




 A SurfaceGO.T is a geometric objects which is composed of surfaces
   (as opposed to lines). Surfaces differ from non-surfaces in a number of
   ways:
   \begin{itemize}
   \item Surfaces interact with light sources, non-surfaces don't
   \item Surfaces can be transparent, non-surfaces are always opaque
   \end{itemize}



INTERFACE SurfaceGO;

IMPORT BooleanProp, Color, ColorProp, GO, LineTypeProp, RasterModeProp,
       RealProp, ShadingProp;

TYPE T <: GO.T;

 A SurfaceGO.T is a subtype of \type{GO}{T}. No additional fields or
   methods are revealed to the user. 

VAR
  DistinguishFacets        : BooleanProp.Name;
  Colour                   : ColorProp.Name;
  BackColour               : ColorProp.Name;
  RasterMode               : RasterModeProp.Name;
  AmbientReflectionCoeff   : RealProp.Name;
  DiffuseReflectionCoeff   : RealProp.Name;
  SpecularReflectionCoeff  : RealProp.Name;
  SpecularReflectionConc   : RealProp.Name;
  TransmissionCoeff        : RealProp.Name;
  SpecularReflectionColour : ColorProp.Name;
  Lighting                 : BooleanProp.Name;
  Shading                  : ShadingProp.Name;
  EdgeVisibility           : BooleanProp.Name;
  EdgeColour               : ColorProp.Name;
  EdgeType                 : LineTypeProp.Name;
  EdgeWidth                : RealProp.Name;

 In addition to the properties observed by all \type{GO}{T}'s, there are
   various additional properties that are observed by SurfaceGO.T's:


   DistinguishFacets is the name of a boolean property that decides whether
   front- and back-faces of surfaces should be distinguished. If this property
   is not specified, front- and back-faces are not distinguished.


   {\em NOTE: In order for this property to make sense, I should introduce
   other surface-related properties: All properties from Colour to
   Shading could have backface analogs.}


   Color is the name of a color property that specifies the color of the
   surface. If this property is not specified, the surface is drawn in white.


   RasterMode is the name of an raster mode property that specifies what
   rasterization technique is used to draw the surface (solid, hollow, or
   empty). If this property is not specified, the surface is drawn solid.


   AmbientReflectionCoeff is the name of a real property that specifies the
   ambient reflection coefficient of the surface. If this property is not
   specified, the ambient reflection coefficient is taken to be 0.5.


   DiffuseReflectionCoeff is the name of a real property that specifies the
   diffuse reflection coefficient of the surface. If this property is not
   specified, the diffuse reflection coefficient is taken to be 1.


   SpecularReflectionCoeff is the name of a real property that specifies the
   specular reflection coefficient of the surface. If this property is not
   specified, the specular reflection coefficient is taken to be 0.


   SpecularReflectionConc is the name of a real property that specifies the
   specular reflection concentration of the surface. If this property is not
   specified, the specular reflection concentration is taken to be 0.


   TransmissionCoeff is the name of a real property that specifies the
   transparency of the surface (with 0 being completely opaque and 1 being
   completely transparent). If this property is not specified, the
   transmission coefficient is taken to be 0.


   SpecularReflectionColour is the name of a color property that specifies
   the color of specular reflected light. If this property is not specified,
   the specular reflection color is taken to be white.


   Lighting is the name of a boolean property that decides whether or not
   lighting and shading computations shall be performed. If this property is
   not specified, lighting and shading computations are performed.


   Shading is the name of a shading property that specifies what shading
   method shall be used. If this property is not specified, flat shading is
   used.


   EdgeVisibility is the name of a boolean property that specifies whether
   or not the edges of the individual polygons of the surface shall be
   outlined. If this property is not specified, no surface edges will be drawn.


   EdgeColour is the name of a color property that determines the color
   of the surface edges (if they are visible). If this property is not
   specified and edges are visible, they are drawn in white.


   EdgeType is the name of a line type property that determines the line
   type of the surface edges (provided they are visible). If this property
   is not specified and edges are visible, they are drawn solid.


   EdgeWidth is the name of a real property that determines the width of the
   surface edges (provided they are visible). If this property is not specified
   and edges are visible, they are drawn with a width of 1.


   The following procedures provide sugaring to attach surface-related
   properties to geometric objects: 


PROCEDURE SetDistinguishFacets (o : GO.T; v : BOOLEAN);

 The expression SetDistinguishFacets(o,v) is equivalent to
   o.setProp(DistinguishFacets.bind(BooleanProp.NewConst(v))). 

PROCEDURE SetColour (o : GO.T; v : Color.T);

 The expression SetColour(o,v) is equivalent to
   o.setProp(Colour.bind(ColorProp.NewConst(v))). 

PROCEDURE SetBackColour (o : GO.T; v : Color.T);

 The expression SetBackColour(o,v) is equivalent to
   o.setProp(BackColour.bind(ColorProp.NewConst(v))). 

PROCEDURE SetRasterMode (o : GO.T; v : RasterModeProp.Kind);

 The expression SetRasterMode(o,v) is equivalent to
   o.setProp(RasterMode.bind(RasterModeProp.NewConst(v))). 

PROCEDURE SetAmbientReflectionCoeff (o : GO.T; v : REAL);

 The expression SetAmbientReflectionCoeff(o,v) is equivalent to
   o.setProp(AmbientReflectionCoeff.bind(RealProp.NewConst(v))). 

PROCEDURE SetDiffuseReflectionCoeff (o : GO.T; v : REAL);

 The expression SetDiffuseReflectionCoeff(o,v) is equivalent to
   o.setProp(DiffuseReflectionCoeff.bind(RealProp.NewConst(v))). 

PROCEDURE SetSpecularReflectionCoeff (o : GO.T; v : REAL);

 The expression SetSpecularReflectionCoeff(o,v) is equivalent to
   o.setProp(SpecularReflectionCoeff.bind(RealProp.NewConst(v))). 

PROCEDURE SetSpecularReflectionConc (o : GO.T; v : REAL);

 The expression SetSpecularReflectionConc(o,v) is equivalent to
   o.setProp(SpecularReflectionConc.bind(RealProp.NewConst(v))). 

PROCEDURE SetTransmissionCoeff (o : GO.T; v : REAL);

 The expression SetTransmissionCoeff(o,v) is equivalent to
   o.setProp(TransmissionCoeff.bind(RealProp.NewConst(v))). 

PROCEDURE SetSpecularReflectionColour (o : GO.T; v : Color.T);

 The expression SetSpecularReflectionColour(o,v) is equivalent to
   o.setProp(SpecularReflectionColour.bind(ColorProp.NewConst(v))). 

PROCEDURE SetLighting (o : GO.T; v : BOOLEAN);

 The expression SetLighting(o,v) is equivalent to
   o.setProp(Lighting.bind(BooleanProp.NewConst(v))). 

PROCEDURE SetShading (o : GO.T; v : ShadingProp.Kind);

 The expression SetShading(o,v) is equivalent to
   o.setProp(Shading.bind(ShadingProp.NewConst(v))). 

PROCEDURE SetEdgeVisibility (o : GO.T; v : BOOLEAN);

 The expression SetEdgeVisibility(o,v) is equivalent to
   o.setProp(EdgeVisibility.bind(BooleanProp.NewConst(v))). 

PROCEDURE SetEdgeColour (o : GO.T; v : Color.T);

 The expression SetEdgeColour(o,v) is equivalent to
   o.setProp(EdgeColour.bind(ColorProp.NewConst(v))). 

PROCEDURE SetEdgeType (o : GO.T; v : LineTypeProp.Kind);

 The expression SetEdgeType(o,v) is equivalent to
   o.setProp(EdgeType.bind(LineTypeProp.NewConst(v))). 

PROCEDURE SetEdgeWidth (o : GO.T; v : REAL);

 The expression SetEdgeWidth(o,v) is equivalent to
   o.setProp(EdgeWidth.bind(RealProp.NewConst(v))). 

END SurfaceGO.