Method and apparatus for performing tangent space lighting and

105 Pages·2013·6.74 MB·English

US006771264B1
(12) United States Patent (10) Patent N0.: US 6,771,264 B1
Duluk et al. (45) Date of Patent: Aug. 3, 2004
(54) METHOD AND APPARATUS FOR OTHER PUBLICATIONS
PERFORMING TANGENT SPACE LIGHTING
AND BUMP MAPPING IN A DEFERRED Angel (interactive computer graphics: a top—doWn approach
SHADING GRAPHICS PROCESSOR With OpenGl: ISBN: 0—201—85571—2—sections 6.8 &
7.7.2).
(75) Inventors: Jerome F. Duluk, Palo Alto, CA (US);
Schilling et al., “Texram: a smart memory for texturing,”
Stephen L. Dodgen, Boulder Creek,
IEEE computer graphics and applications, 5/96, 32—41.
CA (US); Joseph P. Bratt, San Jose,
CA (US); Matthew Papakipos, Menlo
Park, CA (US); Nathan Tuck, San Primary Examiner—MattheW Luu
Diego, CA (US); Richard E. Hesse], (74) Attorney, Agent, or Firm—R. Michael Ananian;
Pleasanton, CA (US) Dorsey & Whitney LLP
(73) Assignee: Apple Computer, Inc., Cupertino, CA (57) ABSTRACT
(Us)
A system and method for performing tangent space lighting
( * ) Notice: Subject to any disclaimer, the term of this in a deferred shading graphics processor (DSGP) encom
patent is extended or adjusted under 35 passes blocks of the DSGP that preprocess data and a Phong
U.S.C. 154(b) by 0 days. shader that executes only after all fragments have been
preprocessed. A preprocessor block receives texture maps
(21) Appl. No.: 09/213,990 speci?ed in a variety of formats and converts those texture
maps to a common format for use by the Phong shader. The
(22) Filed: Dec. 17, 1999 preprocessor blocks provide the Phong shader With interpo
lated surface basis vectors (v5, v,, n), a vector Tb that
(Under 37 CFR 1.47)
represents in tangen/obj ect space the texture/bump data from
(51) Int. Cl.7 .............................................. .. G06T 15/60 the texture maps, light data, material data, eye coordinates
(52) U.S. Cl. ...................................... .. 345/426; 345/584 and other information used by the Phong shader to perform
the lighting and bump mapping computations. The data from
(58) Field of Search ............................... .. 345/426, 582,
345/583, 584 the preprocessor is provided for each fragment for Which
lighting effects need to be computed. The Phong shader
(56) References Cited computes the color of a fragment using the information
provided by the preprocessor. The Phong shader performs all
U.S. PATENT DOCUMENTS
lighting computations in eye space, Which requires it ?rst to
4,783,829 A 11/ 1988 Miyakawa et 211. transform bump data from tangent space to eye space. In one
4,945,500 A 7/1990 Deering embodiment the Phong hardWare does this by multiplying a
4,970,636 A 11/1990 Snodgrass et 81. matrix M Whose columns comprise eye space basis vectors
5,083,287 A 1/1992 Obata et 81. (b5, b,, n) derived from the surface basis vectors (v5, v,, n)
5,123,085 A 6/1992 Wells et 81.
and the vector Tb of bump map data. The eye space basis
5,402,532 A 3/1995 Epstein et 81.
vectors are derived by the DSGP preprocessor so that the
5,448,690 A 9/1995 Shiraishi et 81.
multiplication (M><Tb) gives the perturbed surface normal
5,455,900 A 10/1995 Shiraishi et 81.
5,481,669 A 1/1996 Poulton et 81. N‘ in eye space, re?ecting the bump effects. The perturbed
surface normal N‘ is subsequently used in the lighting
5,574,836 A 11/1996 Broemmelsiek .......... .. 395/127
5,579,455 A 11/1996 Greene et 81. computations.
5,596,686 A 1/1997 Duluk, Jr.
(List continued on next page.) 35 Claims, 41 Drawing Sheets
SM
US 6,771,264 B1
Page 2
US. PATENT DOCUMENTS 5,920,326 A 7/1999 Rentschler et a1. ....... .. 345/503
_ 5,949,424 A * 9/1999 Cabral et a1. ............. .. 345/426
576647071 A 9/1997 Nagashlma 5,949,428 A 9/1999 Toelle et 211.
27233723? 2 15/133; g‘?alllllet al-l 5,977,977 A 11/1999 Kajiya et a1.
7 7 / I a e‘ a‘ 5,990,904 A 11/1999 Grif?n
5,710,876 A 1/1998 Peercy et a1. ............. .. 395/126
. 6,002,410 A 12/1999 Battle
5,767,859 A 6/1998 ROSSlIl et a1. _
5,798,770 A 8/1998 Baldwl. n 6,002,412 A 12/1999 Schlnnerer
5,828,378 A 10/1998 Shl.r al. shl. 6,118,452 A 9/2000 Gannet_ t
6,128,000 A 10/2000 Jouppl et 211.
5,841,447 A 11/1998 DreWs
6,167,486 A 12/2000 Lee et 211.
5,850,225 A 12/1998 Cosman ,
6,204,859 B1 3/2001 Jouppl et 211.
5,854,631 A 12/1998 Akeley et a1.
. 6,229,553 B1 5/2001 Duluk, Jr. et 211.
5,860,158 A 1/1999 Pal et a1.
.. 6,246,415 B1 6/2001 Grossman et 211.
5,864,342 A 1/1999 Kapya et a1. 6259 452 B1 72001 C t 1
RE36,145 E 3/1999 DeAguiar et a1. 7 7 / 0mg 6 a'
5,880,736 A 3/1999 Peercy et a1. ............. .. 345/426
5,889,997 A 3/1999 Strunk * cited by examiner

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