
DIRECTORY Atom, G3dBasic, G3dLight, G3dVector, IO, Real, RealFns, Rope, TiogaOps, ViewerClasses, ViewerOps, ViewerTools;

G3dLightImpl: CEDAR PROGRAM
IMPORTS Atom, G3dVector, IO, Real, RealFns, Rope, TiogaOps, ViewerOps, ViewerTools
EXPORTS G3dLight

~ BEGIN
RGB:					TYPE ~ G3dLight.RGB;
ROPE:					TYPE ~ Rope.ROPE;
PropList:				TYPE ~ Atom.PropList;
Triple:				TYPE ~ G3dBasic.Triple;
Light:					TYPE ~ G3dLight.Light;
LightProc:			TYPE ~ G3dLight.LightProc;
LightRep:				TYPE ~ G3dLight.LightRep;
LightSequence:		TYPE ~ G3dLight.LightSequence;
LightSequenceRep:	TYPE ~ G3dLight.LightSequenceRep;
Error:				PUBLIC SIGNAL [code: ATOM, reason: ROPE] = CODE;
DefaultIllumination: LightProc ~ {
d: REAL м G3dVector.Length[G3dVector.Sub[position, light.position]];
strength: REAL м RealFns.Power[(light.radius-d)/light.radius, light.exponent]; 
RETURN[[light.color.R*strength, light.color.G*strength, light.color.B*strength]];
};

LightDots: PUBLIC PROC [light: Light, normal, eyeView: Triple]
RETURNS [nDotE, nDotH, nDotL: REAL]
~ {
nDotE м -G3dVector.Dot[normal, eyeView]; -- want direction to, not from eye
nDotH м G3dVector.Dot[normal, light.highlight];
nDotL м G3dVector.Dot[normal, light.direction];
};

SpecularFromDots: PUBLIC PROC [light: Light, nDotE, nDotH, nDotL: REAL]
RETURNS [REAL]
~ {
g: REAL м IF nDotE < nDotL
THEN IF 2.0*nDotE*nDotH < light.eDotH
THEN 2.0*nDotH/light.eDotH
ELSE 1.0/nDotE
ELSE IF 2.0*nDotL*nDotH < light.eDotH
THEN 2.0*nDotH*nDotL/(light.eDotH*nDotE)
ELSE 1.0/nDotE;
t: REAL м light.b/(nDotH*nDotH+light.a);
d: REAL м t*t;
RETURN[MAX[0.0, d*g*light.f]];
};
AddLight: PUBLIC PROC [
lights: LightSequence,
name: ROPE,
position, direction: Triple,
color: RGB м [1,1,1],
eyeView: Triple м []]
RETURNS [LightSequence]
~ {
light: Light м NEW[LightRep]; -- make new light of given type
light.name м name;
light.position м position;
light.color м color;
light.direction м direction;
PrepareLight[light, eyeView];
IF lights = NIL THEN lights м NEW[LightSequenceRep[1]];
FOR n: NAT IN [0..lights.length) DO
IF NOT Rope.Equal[lights[n].name, light.name, FALSE] THEN LOOP;
lights[n] м light;
EXIT;
REPEAT
FINISHED => {
IF lights.length = lights.maxLength THEN lights м LengthenLightSequence[lights];
lights[lights.length] м light;
lights.length м lights.length+1;
};
ENDLOOP;
RETURN[lights];
};

LengthenLightSequence: PUBLIC PROC [lights: LightSequence]
RETURNS [new: LightSequence] ~ {
newLength: NAT м MAX[Real.Round[1.3*lights.length], 3];
new м NEW[LightSequenceRep[newLength]];
FOR i: NAT IN [0..lights.length) DO new[i] м lights[i]; ENDLOOP;
new.length м lights.length;
};

DeleteLight: PUBLIC PROC [lights: LightSequence, name: ROPE] ~ {
n: INTEGER м -1;
IF lights = NIL THEN RETURN;
FOR i: NAT IN [0..lights.length) DO
IF Rope.Equal[lights[i].name, name, FALSE] THEN {n м i; EXIT};
ENDLOOP;
IF n = -1 THEN RETURN;
FOR nn: INT IN [n..lights.length-1) DO lights[nn] м lights[nn+1]; ENDLOOP;
lights.length м lights.length-1;
};

PrepareLight: PUBLIC PROC [light: Light, eyeView: Triple] ~ {
indexOfRefraction: REAL ~ 200.0;
specularCharacteristic: REAL ~ 0.35;
r, rSubQ, rAddQ, qrAddQ, qrSubQ, q: REAL;
light.position м G3dVector.Unit[light.position]; -- keep to unit sphere, for user interaction
light.direction м G3dVector.Unit[light.direction];
light.highlight м G3dVector.Unit[G3dVector.Add[eyeView, light.direction]];
q м light.eDotH м G3dVector.Dot[eyeView, light.direction];
r м RealFns.SqRt[indexOfRefraction*indexOfRefraction+q*q-1.0];
rSubQ м r-light.eDotH;
rAddQ м r+light.eDotH;
qrAddQ м light.eDotH*rAddQ-1.0;
qrSubQ м light.eDotH*rSubQ+1.0;
light.f м ((rSubQ*rSubQ)/(rAddQ*rAddQ))*(1.0+(qrAddQ*qrAddQ)/(qrSubQ*qrSubQ));
light.a м 1.0/(specularCharacteristic*specularCharacteristic-1.0);
light.b м light.a+1.0;
IF light.lightProc = NIL THEN light.lightProc м DefaultIllumination;
};

PrepareLights: PUBLIC PROC [lights: LightSequence, eyeView: Triple]
RETURNS [LightSequence]
~ {
IF lights = NIL THEN lights м AddLight[NIL, "Light1", [200.0, 100.0, 100.0], [1.0, 0.0, 0.0]];
FOR n: NAT IN [0..lights.length) DO PrepareLight[lights[n], eyeView]; ENDLOOP;
RETURN[lights];
};
registeredLights:	PropList м NIL;			-- registered lights

RegisterLight: PUBLIC PROC [light: Light, type: ATOM] ~ {
registeredLights м Atom.PutPropOnList[registeredLights, type, NEW[LightRep м lightн]];
};
	
GetRegisteredLight: PUBLIC PROC [type: ATOM] RETURNS [light: Light] ~ {
ref: Light м NARROW[Atom.GetPropFromList[registeredLights, type]];
IF ref # NIL 
THEN light м NEW[LightRep м refн] 
ELSE Error[$Unimplemented, "Unregistered light type"];
};

InitDefaultLightClasses: PUBLIC PROC ~ {
defaultLight: Light м NEW[LightRep];
defaultLight.lightProc м DefaultIllumination;
RegisterLight[defaultLight, $Default];
};
RopeFromLights: PUBLIC PROC [lights: LightSequence] RETURNS [r: ROPE] ~ {
r м "Lights: \n";
IF lights # NIL THEN
FOR n: NAT IN [0..lights.length) DO
l: Light м lights[n];
r м Rope.Concat[r, IO.PutFLR["\t%g: pos: [%g, %g, %g]",
LIST[IO.rope[l.name], IO.real[l.position.x], IO.real[l.position.y], IO.real[l.position.z]]]];
r м Rope.Concat[r, IO.PutFR[" color: [%g, %g, %g]",
IO.real[l.color.R], IO.real[l.color.G], IO.real[l.color.B]]];
r м Rope.Concat[r, "\n"];
ENDLOOP;
};

AnnotateLightsToViewer: PUBLIC PROC [lights: LightSequence, viewerName: ROPE] ~ {
GetViewer: PROC RETURNS [v: ViewerClasses.Viewer] ~ {
IF (v м ViewerOps.FindViewer[viewerName]) # NIL THEN RETURN;
v м ViewerTools.MakeNewTextViewer[[name:viewerName, file:viewerName, column:right]];
ViewerOps.OpenIcon[v];
};
v: ViewerClasses.Viewer м GetViewer[];
lastLoc: TiogaOps.Location м TiogaOps.LastLocWithin[TiogaOps.ViewerDoc[v]];
TiogaOps.SetSelection[v, lastLoc, lastLoc];
TiogaOps.SetLooks["b"];
TiogaOps.InsertRope["Lights:"];
TiogaOps.Break[];
TiogaOps.Nest[];
IF lights # NIL THEN FOR n: NAT IN [0..lights.length) DO
l: Light м lights[n];
TiogaOps.SetLooks["b"];
TiogaOps.InsertRope[l.name];
TiogaOps.SetLooks[" "];
TiogaOps.InsertRope[IO.PutFR[": pos: (%g, %g, %g)",
IO.real[l.position.x], IO.real[l.position.y], IO.real[l.position.z]]];
TiogaOps.InsertRope[IO.PutFR[" color: [%g, %g, %g]",
IO.real[l.color.R], IO.real[l.color.G], IO.real[l.color.B]]];
TiogaOps.Break[];
ENDLOOP;
TiogaOps.UnNest[];
};
InitDefaultLightClasses[];
END.

   ╩  
G3dLightImpl.mesa
Copyright ╙ 1988, 1992 by Xerox Corporation.  All rights reserved.
Bloomenthal, July 15, 1992 10:47 pm PDT
Glassner, January 23, 1989 9:34:54 am PST
Crow, May 16, 1989 6:28:52 pm PDT
Imported Types
Errors
Lighting
Local Phong shading:

Modified Torrance-Sparrow (Blinn) shading:

Light Sequences
Preparation
From Blinn: Models of Light Reflection for Computer Synthesized Pictures, Siggraph '77.
Registration
Miscellany
Start Code

 Э╩╢  ХNewlineDelimiter
Ц"cedarcode" styleЩ ЩJЪЬ	╧eЬ6ЩBJЩ'JЪЬ&╧kЩ)JЪЬЮЩ!JШ JЪЮ	Ь&ЮЬGШxJШ ЧЪ╤blnЬЮЬЮШJЪЮЬЮЬ7ШRJЪЮЬ	ШJШ ЧJЪЬЮШheadЪ╧lЩJЪЮЬЮЬЮЬШJЪЮЬЮЬЮЬШJЪЬЮЬШ"JЪЬЮЬШ"JЪЬЮЬШ!JЪЬЮЬШ'JЪЬЮЬШ&JЪЬЮЬШ.JЪЬЮЬШ3ЧЪаЩJЪ╧nЬЮЬЮЬЮЬ
ЮЬЮЬШ:ЧЪаЩЩJЩ ЪбЬШ"JЪЬЮЬ=ШDJЪЬ
ЮЬAШOJЪЮЬKШQJШJШ ЧЧЩ*JЩ Ъб	ЬЮЬЮЬ(Ш>JЪЮЬЮЬШ#JШJЪЬ)╧c"ШKJШ/JШ/JШJШ ЧЪбЬЮЬЮЬ%ЮЬШGJЪЮЬЮЬШJШЪЬЮЬЮЬШЪЮЬЮЬШ%JЪЮЬШJЪЮЬ
ШЧЪЮЬЮЬШ%JЪЮЬ$Ш(JЪЮЬШЧЧJЪЬЮЬ!Ш(JЪЬЮЬШJЪЮЬЮЬШJШЧЧЧЪаЩЪбЬЮЬЮЬШJЪЬШJЪЬ╧sЮЬШJЪЬгЬШJЪЬгЮгЬгЬШJШJЪЮЬШJШJЪЬЮЬвШ=JШJШJШJШJЪЬШJЪЮЬ
ЮЬЮЬ
ЮЬШ7ЪЮЬЮЬЮЬЮШ#JЪ
ЮЬЮЬ(ЮЬЮЬЮЬШ?JШJЪЮЬШJЪЮШЪЮЬШJЪЮЬ"ЮЬ(ШPJШJШ JШЧJЪЮЬШЧJЪЮЬ	ШJШJШ ЧЪбЬЮЬЮЬШ:JЪЮЬШ JЪЬЮЬЮЬ#Ш7JЪЬЮЬШ'JЪ
ЮЬЮЬЮЬЮЬЮЬШ@JШJШJШ ЧЪбЬЮЬЮЬЮЬШ@JЪЬЮЬШJЪЮЬ
ЮЬЮЬЮЬШЪЮЬЮЬЮЬЮШ#JЪЮЬ"ЮЬЮЬ	ЮЬШ>JЪЮЬШЧJЪЮЬЮЬЮЬШJЪ
ЮЬЮЬЮЬЮЬЮЬШJJШ JШЧЧЪаЩJШ ЪбЬЮЬЮЬ$Ш=ЩWJЪЬЮЬ	Ш JЪЬЮЬШ$JЪЬ$ЮЬШ)JЪЬ1в,Ш]JШ2JШJJШ:JШ>JШJШJШJШJШNJШBJШJЪЮЬЮЬЮЬ'ШDЧJШJШ ЧЪбЬЮЬЮЬ)ШCJЪЮЬШJШJЪЮЬ
ЮЬЮЬЮЬ4Ш^JЪ
ЮЬЮЬЮЬЮЬ#ЮЬШNJЪЮЬ	ШJШЧЧЪаЩJЪЬЮЬвШ8JШ ЪбЬЮЬЮЬЮЬШ9JЪ
ЬгЬ&гЬгЮЬ	гЬШVJШЧЪ
бЬЮЬЮЬЮЬЮЬШGJЪЬЮЬ/ШBЪЮЬЮЬШJЪЮЬ	ЮЬШ"JЪЮЬ2Ш6ЧJШJШ ЧЪбЬЮЬЮЬШ(JЪЬЮЬШ$JШ-JЪЬ&Ш&JЪЬШЧЧЪа
Щ
Ъ
бЬЮЬЮЬЮЬЮЬШIJШЪЮЬ
ЮЬЮШЪЮЬЮЬЮЬЮШ#JШЪЬЮЬ"Ш7JЪ
ЮЬЮЬЮЬЮЬЮЬШ]ЧЪЬЮЬШ3JЪЮЬЮЬЮЬШ=ЧJШJЪЮЬШЧЧJШJШ ЧЪбЬЮЬ%ЮЬШQЪб	ЬЮЬЮЬШ5JЪЮЬ*ЮЬЮЬЮЬШ<JЪ	ЬгЬгЬ/гЬгЬШTJЪЬШJШЧJШ&JШKJЪЬ+Ш+JШJШJШJШЪЮЬ
ЮЬЮЬЮЬЮЬЮШ8JШJЪЬШJЪЬШJЪЬШЪЬЮЬШ3JЪЮЬЮЬЮЬШFЧЪЬЮЬШ4JЪЮЬЮЬЮЬШ=ЧJШJЪЮЬШЧJШJШЧЧЪа
Щ
JЪЬШJЩ ЧJЪЮЬШJШ Ч ЕЧ    d  !ф  