DIRECTORY
Rope					USING [ROPE],
Atom					USING [PropList],
IO						USING [STREAM],
Imager				USING [Rectangle, Context],
ImagerColor			USING [RGB],
Vector2				USING [VEC],
Pixels					USING [Extent, PixelBuffer],
ScanConvert			USING [RealSequence, GetColorProc],
Vector3d				USING [Triple, Quad],
Matrix3d				USING [Matrix];
ThreeDScenes: CEDAR DEFINITIONS
~ BEGIN
Error: SIGNAL [reason: ErrorDesc];
ErrorDesc: TYPE ~ RECORD [code: ATOM, explanation: Rope.ROPE];

RGB: TYPE ~ ImagerColor.RGB;
Pair: TYPE ~ Vector2.VEC;											-- RECORD [ x, y: REAL];
Triple: TYPE ~ Vector3d.Triple;								-- RECORD [ x, y, z: REAL];
Quad: TYPE ~ Vector3d.Quad;									-- RECORD [ x, y, z, w: REAL];
Rectangle: TYPE ~ Pixels.Extent;
RealSequence: TYPE ~ ScanConvert.RealSequence;
Xfm3D: TYPE ~ Matrix3d.Matrix;	-- REF ARRAY [0..4) OF ARRAY [0..4) OF REAL
ScaleAndAddXfm: TYPE ~ RECORD[scaleX, scaleY, scaleZ, addX, addY, addZ: REAL];

Box: TYPE ~ RECORD[left, right, bottom, top: NAT]; 			-- bounding box for limit tests
SixSides: TYPE ~ {Left, Right, Bottom, Top, Near, Far};
OutCode: TYPE ~ RECORD[left, right, bottom, top, near, far: BOOLEAN];
NoneOut: OutCode ~ [FALSE, FALSE, FALSE, FALSE, FALSE, FALSE];
AllOut: OutCode ~ [TRUE, TRUE, TRUE, TRUE, TRUE, TRUE];
Vertex: TYPE ~ RECORD[ 
x,y,z: REAL _ 0.0, 				-- object coordinates
ex, ey, ez: REAL _ 0.0, 		-- eyespace coordinates
sx, sy, sz: REAL _ 0.0, 			-- screen coordinates
clip: OutCode _ NoneOut	-- clip code
];
VertexSequence: TYPE ~ RECORD[SEQUENCE length: CARDINAL OF REF Vertex];

ShadingValue: TYPE ~ RECORD[ 
xn,yn,zn: REAL _ 0.0,  		-- normal vector to surface
r,g,b: REAL _ 0.7,  				-- original color (default grey)
t: REAL _ 0.0,					-- original transmittance
txtrX,txtrY,txtrZ: REAL _ 0.0, 	-- texture coordinates
exn,eyn,ezn: REAL _ 0.0, 		-- normal in eyespace 
ir,ig,ib,it: CARDINAL _ 0  -- computed color and transmittance (for current lights, view, etc.)
];
ShadingSequence: TYPE ~ RECORD[SEQUENCE length: CARDINAL OF REF ShadingValue];
VertexInfo: TYPE ~ RECORD[coord: Vertex, shade: ShadingValue, props: Atom.PropList];
VertexInfoSequence: TYPE ~ RECORD [SEQUENCE length: CARDINAL OF REF VertexInfo];
VtxToRealSeqProc: TYPE ~ PROC[dest: REF RealSequence, source: VertexInfo] 
								RETURNS[REF RealSequence];
ShadingProcs: TYPE ~ RECORD [VtxToRealSeqProc, ScanConvert.GetColorProc];
ClipState: TYPE ~ { in, out, clipped };
ShapeInstance: TYPE ~ RECORD[
type: ATOM _ NIL,								-- eg. $ConvexPolygon, $Bezier, $Light, etc.
insideVisible: BOOLEAN _ FALSE,				-- closed (or open) surface
name: Rope.ROPE _ NIL, 						-- local name for Shape (allows instancing)
fileName: Rope.ROPE _ NIL, 					-- file name (should be on a server)
location: Triple _ [0.,0.,0.],						-- position in scene space (last transform)
orientation: Triple _ [0.,0.,1.],					-- vector defining orientation (second transform)
rotation: REAL _ 0.,								-- rotation about rotation axis (first transform)
axisBase: Triple _ [0.,0.,0.],						-- rotation axis:  direction = End - Base
axisEnd: Triple _ [0.,0.,1.],						-- 				rotation is about base point
position: Xfm3D _ NIL,						-- transform from definition space to world space
positionInValid: BOOLEAN _ TRUE, 			-- location, orientation, or rotation changed
clipState: ClipState _ in, 						-- { in, out, clipped }
shadingInValid: BOOLEAN _ TRUE, 			-- true if light or object changed
vtcesInValid: BOOLEAN _ TRUE,				-- true if object or view changed
centroid: Vertex, 								-- bounding sphere
boundingRadius: REAL _ 0.0,
screenExtent: Box _ [0, 0, 0, 0],				-- extent on screen (when position valid)
vertex: REF VertexSequence _ NIL,			-- location and clip codes for defining points
shade: REF ShadingSequence _ NIL, 			-- shading at defining points
numSurfaces: NAT _ 0, 						-- number of surface elements
surface: REF ANY _ NIL,						-- surface definition using defining points
shadingProps: Atom.PropList _ NIL,			-- shading definition
props: Atom.PropList _ NIL						-- catchall
];
ShapeSequence: TYPE ~ RECORD[SEQUENCE length: CARDINAL OF REF ShapeInstance];

Context: TYPE ~ RECORD [
shapes: REF ShapeSequence _ NIL,			-- current collection of shapes in environment
lights: REF ShapeSequence _ NIL,				-- current light sources
environment: Atom.PropList _ NIL,			-- for reflection map, ambient light proc, etc. 
eyePoint: Triple _ [1.0, -5.0, 2.0],	       -- defines point from which view is seen
ptOfInterest: Triple _ [0.,0.,0.],				-- defines center of image and focus
rollAngle: REAL _ 0.,							-- rotational angle about direction of view
upDirection: Triple _ [0.,0.,1.],				-- defines "heads-up" direction (redundant)
fieldOfView: REAL _ 40.,						-- horizontal angle included in field of view
window: Imager.Rectangle _ [-1.,-1., 2., 2.],	-- window clips field of view in eyespace
hitherLimit: REAL _ 1.,							-- anything closer to eyepoint is clipped
yonLimit: REAL _ 1000.,						-- anything further from eyepoint is clipped
clippingPlanes: ARRAY SixSides OF Quad, 	-- computed clip planes
eyeSpaceXfm: Xfm3D _ NIL,				-- world space to eyespace
eyeToNDC: ScaleAndAddXfm _ [1.,1.,1., 0.,0.,0.],	-- eyespace to normalized display coords
display: Pixels.PixelBuffer,	       -- display-specific info
viewPort: Imager.Rectangle,					-- viewport in floating pt. display coordinates
extentCovered: Box _ [0, 0, 0, 0],				-- bounds area used (while building image)
renderMode: ATOM _ NIL,			-- {$Dithered, $PseudoClr, $Grey, $Dorado24, $FullClr }
alphaBuffer: BOOLEAN _ FALSE,				-- buffer for matting and antialiasing
depthBuffer: BOOLEAN _ FALSE,				-- buffer for cheap hidden-surface removal
lineDrawing: BOOLEAN _ FALSE,				-- vector or shaded representation
depthResolution: NAT _ 8192,	       -- number of buckets for depth sorting
sortSequence: REF _ NIL,						-- shapes or surfaces sorted for display
props: Atom.PropList _ NIL	       -- catchall
];
GetFromImagerContext: PROC[ imagerCtx: Imager.Context, 
									  alpha, depth, grey: BOOLEAN _ FALSE ]
							  RETURNS [REF Context];
Create: PROC[ width, height: NAT, renderMode: ATOM, alpha, depth: BOOLEAN _ FALSE ]
		 RETURNS [REF Context];
SetEyeSpace: PROC[ context: REF Context ];				-- get worldspace to eyespace matrix
SetWindow: PROC[context: REF Context, size: Imager.Rectangle];
WindowFromViewPort: PROC[viewPort: Imager.Rectangle] RETURNS[Imager.Rectangle];
SetViewPort: PROC[context: REF Context, size: Imager.Rectangle, clear: BOOLEAN _ FALSE];
FillViewPort: PROC[context: REF Context, clr: RGB];	-- clears for new image
FillInBackGround: PROC[context: REF Context];	-- loads background behind current image
SetView: PROC[context: REF Context, eyePoint, ptOfInterest: Triple, fieldOfView: REAL _ 40.0, 
				  rollAngle: REAL _ 0.0, upDirection: Triple _ [ 0., 0., 1.], 
				  hitherLimit: REAL _ .01, yonLimit: REAL _ 1000.0];
SetLight: PROC[context: REF Context, name: Rope.ROPE, position: Triple, color: RGB _ [1., 1., 1.]] 
		   RETURNS[REF ShapeInstance];
DeleteLight: PROC[context: REF Context, name: Rope.ROPE];
GetAmbientLight: PROC[context: REF Context, normal: Triple] RETURNS[RGB];
ReadScene: PROC[context: REF Context, input: IO.STREAM];
WriteScene: PROC[context: REF Context, output: IO.STREAM];
NewShape: PROC[ name: Rope.ROPE ] RETURNS[REF ShapeInstance];
FindShape: PROC[ set: REF ShapeSequence, name: Rope.ROPE ] RETURNS[REF ShapeInstance];
AddShape: PROC[ set: REF ShapeSequence, shape: REF ShapeInstance ] 
			 RETURNS[REF ShapeSequence]; 
DeleteShape: PROC[ set: REF ShapeSequence, name: Rope.ROPE ] RETURNS[REF ShapeSequence];
CopyShape: PROC[ shape: REF ShapeInstance, newName: Rope.ROPE ] 
			   RETURNS[REF ShapeInstance];
PlaceShape: PROC[ shape: REF ShapeInstance, location: Triple];	-- absolute position
MoveShape: PROC[ shape: REF ShapeInstance, delta: Triple];				-- relative position
OrientShape: PROC[ shape: REF ShapeInstance, axis: Triple];				-- tilt from vertical
RotateShape: PUBLIC PROC[ shape: REF ShapeInstance, axisBase, axisEnd: Triple, theta: REAL ];
SetPosition: PROC[shape: REF ShapeInstance, concat: BOOLEAN _ FALSE]; 
PutShading: PROC[ shape: REF ShapeInstance, key: ATOM, value: REF ANY];
GetShading: PROC[ shape: REF ShapeInstance, key: ATOM ] RETURNS [value: REF ANY];

InitShades: PROC[ shape: REF ShapeInstance ] RETURNS[shade: REF ShadingSequence];
SetUpStandardFile: PROC[file: Rope.ROPE] RETURNS [stream: IO.STREAM, numEntries: NAT];
ReadVertexCoords: PROC[vtx: REF VertexSequence, in: IO.STREAM, nVtces: NAT];
ReadTextureCoords: PROC[shade: REF ShadingSequence, in: IO.STREAM, nVtces: NAT];
ReadColors: PROC[shade: REF ShadingSequence, in: IO.STREAM, length: NAT];
ReadNormals: PROC[shade: REF ShadingSequence, in: IO.STREAM, length: NAT];
GetClipCodeForPt: PROC[context: REF Context, pt: Triple] RETURNS[clip: OutCode]; 
XfmPtToEyeSpace: PROC[context: REF Context, pt: Triple] RETURNS[Triple, OutCode]; 
XfmPtToDisplay: PROC[context: REF Context, pt: Triple] RETURNS[Triple];
ShadePt: PROC [context: REF Context, pt: VertexInfo, shininess: REAL]
		  RETURNS [RGB, REAL];
XfmToEyeSpace: PROC[context: REF Context, shape: REF ShapeInstance] RETURNS[ClipState]; 
XfmToDisplay: PROC[context: REF Context, shape: REF ShapeInstance]; 
GetVtxShades: PROC[ context: REF Context, shape: REF ShapeInstance ];

END.

ThreeDScenes.mesa
Copyright c 1984, 1986 by Xerox Corporation.  All rights reserved.
Last Edited by: Crow, May 24, 1986 1:36:49 pm PDT
Basic Types
Vertex Definitions
Shape Definitions (also used for lights)
Uses for ShapeInstance.shadingProps:
- $Type - {$Faceted, $Smooth, $Lines}
- $Color - {REF RGB}
- $Transmittance - {REF REAL}
- $Shininess - {REF REAL}
- $PatchColors - {ShadingValue for each Patch}
Context Definition
Procedures for Setting up Contexts
Sets up context using imager context where possible, options: alpha, depth buffer & greyscale 
Procedures for Defining and Altering Environments
Procedures for Manipulating Shapes
Rotation about arbitrary axis
Get new position matrix or concatenate to previous matrix
Procedures for Manipulating Vertices
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