Patent EP0757333A2 successfully refreshed from Google Patents.
EP0757333A2
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EP
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3D image decoding
Assignee: Sun Microsystems Inc
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Filing: 1996-08-05
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Granted: —
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Expires: 2016-08-05
Abstract
Abstract Three-dimensional compressed geometry is decompressed with a unit having an input FIFO receiving compressed data bits and outputting to an input block state machine and an input block, whose outputs are coupled to a barrel shifter unit. Input block output also is input to Huffman tables that output to the state machine. The state machine output also is coupled to a data path controller whose output is coupled to a tag decoder, and to a normal processor receiving output from the barrel shifter unit. The decompressor unit also includes a position/color processor that receives output from the barrel shifter unit. Outputs from the normal processor and position/color processor are multiplexed to a format converter. For instructions in the data stream that generate output to the format converter, the decompression unit generates a tag sent to the tag decoder in parallel with bits for normals that are sent to the format converter. The decompressed stream of triangle data may then be passed to a traditional rendering pipeline, where it can be processed in full floating point accuracy, and thereafter displayed or otherwise used.
Inventors
- 👤 Michael F. Deering
- 👤 Aaron S. Wynn
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 13:28
CPC Classifications
G; G06; G06T; G06T15/00; G06T17/00; G06T17/20; G06T9/00; G06T9/001
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
145 words
A method for decompressing a data stream of variable length fields, said data stream including op code bits and/or tag bits, which guide decompression of said fields into uncompressed surface characteristics of three-dimensional objects, the method comprising the following steps: (a) detecting from said data stream a field type, wherein data enabling such detecting precedes but not necessarily immediately precedes sequentially within said data stream; (b) detecting from said data stream a field length and/or a field normalization, wherein data enabling such detecting precedes but not necessarily immediately precedes sequentially within said data stream; (c) using information obtained from at least one of step (a) and step (b), extracting bit-aligned fields from said data stream; and (d) renormalizing as necessary extracted said bit-aligned fields to an original numerical scale; and (e) outputting decompressed surface-describing data, said data optionally being in a generalized triangle strip format.
Claim 2
Dependent Claim
155 words
The method of claim 1, wherein: said op code bits represent information pertaining to type of following set of fields, said information selected from the group consisting of (i) vertex information, (ii) position information, (iii) surface normal information, (iv) color, (v) texture map coordinates, (vi) surface material properties, and (vii) procedural information, (viii) procedural information that is a command other than any of a vertex command, a normal command and a color command; and/or said tag bits have at least one characteristic selected from the group consisting of (a) said tag bits implicitly describe at least one field characteristics selected from the group consisting of (i) field length, (ii) normalization, (iii) whether such field is relative, (iv) whether such field is absolute, and (b) said tag bits have a varying length and include information about said varying length as well as possible field content information, said varying length being independent of said field content information.
Claim 3
Dependent Claim
59 words
The method of claim 1 or 2, wherein if at step (b) the enabling data does not immediately sequentially proceed, said method further includes: (b-1) fetching from said data stream a current instruction and a following instruction; (b-2) fetching a fixed number of first bits of said following instruction; and (b-3) then fetching remaining bits for said current instruction.
Claim 4
Independent Claim
132 words
The method of any preceding claim, further including the steps of: (f-1) providing said tag bits to a tag look-up table whose output identifies at least one of (i) start of following data fields, (ii) length of said data fields, (iii) actual tag field length, (iv) identification whether said field is relative, (v) identification whether said field is absolute, and (vi) a renormalization parameter for said data fields including numerical shifting offset information to facilitate renormalization; (f-2) if said tag look-up table output indicates such bit-aligned fields are relative, adding a normalized value of said field to a current value of said field; and (f-3) if said tag look-up table output indicates such bit-aligned fields are absolute, replacing a current value of said field with a said normalized value of said field.
Claim 5
Dependent Claim
72 words
The method of claim 3 or 4, wherein: if a next following instruction is to modify how said bit-aligned fields are interpreted or is to modify contents of said tag look-up table or to pass though unmodified data in said bit-aligned fields, then do so; and if such normalized bit-aligned fields contain normal information, a tag field index is passed through said look-up table to obtain a rectilinear representation of said normal.
Claim 6
Independent Claim
81 words
The method of any preceding claim, wherein said bit-aligned fields contain information relating to at least one characteristic selected from the group consisting of (i) x,y,z coordinate positions on said surface of said object, (ii) red, green, blue color information for said object, (iii) red, green, blue and alpha color information for said object, (iv) differences between sequential red, green, blue color information for said object, and (iv) differences between sequential red, green, blue and alpha color information for said object.
Claim 7
Independent Claim
141 words
The method of any preceding claim, wherein said object has at least one characteristic selected from the group consisting of (i) characteristics of position of said object are represented as rectilinear x, y, z coordinate, (ii) characteristics of color of said object are represented as including at least red, green, blue, and alpha components, said color being selected from the group consisting of at least (a) emissive color, (b) ambient color, (c) diffuse color, and (d) specular color, (iii) characteristics of normals of said object are represented by rectilinear Nx, Ny, and Nz vector coefficients, (iv) characteristics of normals of said object are represented by a normal table index, said surface characteristics of said object include at least one characteristic selected from the group consisting of (a) position, (b) normals, (c) colors, (d) texture map coordinates, and (e) material surface properties.
Claim 8
Dependent Claim
258 words
The method of claim 7, wherein each of said normals is represented by a single index into a table of predefined normalized normals, and wherein said index has at least one characteristic selected from the group consisting of (i) said index includes bits of index representation comprising rectilinear representation sign bits of a normal to be represented, (ii) said index includes at least one bit specifying possible foldings of an absolute magnitude of a rectilinear representation of the normal to be represented by at least one folding plane x=y, x=z, y=z such that a folded normal is ensured to be on a known side of said folding plane, (iii) said index includes bits representing longitude information and latitude information of said normal, (iv) said index is defined to include bits of octant information, bits of sextant information, and additional fields of information about longitude and latitude of the folded normal, (v) said index includes bits representing longitude information and latitude information of said normal, and further includes bits of octant information, bits of sextant information, and additional fields of information about longitude and latitude of the folded normal, (vi) said index is defined to include three-bits of octant information, three-bits of sextant information, and two additional fields of information about longitude and latitude of the folded normal, and (vii) said index includes bits representing longitude information and latitude information of said normal, and further includes three bits of octant information, three-bits of sextant information, and two additional fields of information about longitude and latitude of the folded normal.
Claim 9
Independent Claim
68 words
The method of any preceding claim, wherein said data stream to be decompressed results from said objects having been represented as three-dimensional triangular data defining a plurality of triangles having vertices, which data were converted into linear format defining a generalized triangular mesh, individual ones of said surface characteristics having been quantized, and variable length compression having been applied to a difference between sequential ones said surface characteristics.
Claim 10
Independent Claim
54 words
The method of any preceding claim, further including the following steps: if a current bit-aligned field is to be placed in a mesh buffer, placing a copy of said current bit-aligned field in said mesh buffer; and if said bit-aligned fields contain a mesh buffer reference, accessing old normalized values for said bit-aligned fields.
Claim 11
Independent Claim
131 words
A system, useable with a computer system that includes a central processing unit (CPU) and a memory coupled to said CPU, for decompressing a data stream whose fields can vary in length, said data stream including op code bits and/or tag bits, said data stream including compressed data representing three-dimensional objects whose surface defines surface characteristics, the system including: a detector unit programmed to receive said data stream and to detect from a preceding, but not necessarily immediately sequentially preceding, field in said data stream field information of an immediately following field, said field information including a field type and a field length and/or field normalization; and an extractor unit programmed to receive at least some data detected by said detector unit and to extract bit-aligned fields from said data stream.
Claim 12
Dependent Claim
85 words
The system of claim 11, further including a look-up table, coupled to receive from said detector unit at least a portion of said data stream, providing at least one piece of information selected from the group consisting of (i) tag field start position, (ii) actual tag field length, (iii) identification as to whether said field is relative, (iv) identification as to whether said field is absolute, and (v) numerical shifting offset information; wherein bit-line fields contained in said data stream are aligned to individual bits.
Claim 13
Dependent Claim
132 words
The system of claim 11 or 12, further including at least one unit selected from the group consisting of (i) a multi-stage barrel shifting unit that includes a first stage that aligns new incoming data contained in said data stream, and a second stage that aligns remaining old data contained in said data stream with said new incoming data, (ii) an interface circuit unit coupled to receive said data stream, (iii) a three-dimensional graphics decompressor coupled to an output of said interface circuit and decompressing said data stream, and (iv) a three-dimensional graphics rendering unit, coupled to receive and output a decompressed data stream; wherein at least two of said barrel shifting unit, said interface circuit, said three-dimensional graphics decompressor, and said three-dimensional graphics rendering unit are fabricated on one integrated circuit.
Claim 14
Independent Claim
184 words
The system of any of claims 11 to 13, wherein: said op code bits represent information pertaining to type of following set of fields, said information selected from the group consisting of (i) vertex information, (ii) position information, (iii) surface normal information, (iv) color, (v) texture map coordinates, (vi) surface material properties, and (vii) procedural information, (viii) procedural information that is a command other than any of a vertex command, a normal command and a color command; and/or said tag bits have at least one characteristic selected from the group consisting of (a) said tag bits implicitly describe at least one field characteristics selected from the group consisting of (i) field length, (ii) normalization, (iii) whether such field is relative, (iv) whether such field is absolute, and (b) said tag bits have a varying length and include information about said varying length as well as possible field content information, said varying length being independent of said field content information; wherein at least some of said op code bits and/or said tag bits guide decompression of said fields into uncompressed surface characteristics of three-dimensional objects.
Claim 15
Independent Claim
171 words
The system of any of claims 11 to 14, wherein: said objects have said surface characteristics including at least one characteristic selected from the group consisting of (i) position, (ii) normals, (iii) colors, (iv) texture map coordinates, (v) material surface properties of said object; and/or said objects have at least one characteristic selected from the group consisting of (i) characteristics of position of an object are represented as rectilinear x, y, z coordinate, (ii) characteristics of color of a said object are represented as consisting of at least red, green, blue, and alpha components, said color being selected from the group consisting of at least (a) emissive color, (b) ambient color, (c) diffuse color, and (d) specular color, (iii) characteristics of normals of a said object are represented by rectilinear Nx, Ny, and Nz vector coefficients, (iv) characteristics of normals of a said object are represented by an index into a look-up table of said normals, (v) position, (vi) normals, (vii) colors, (viii) texture map coordinates, and (ix) material surface properties.
Claim 16
Dependent Claim
268 words
The system of claim 15, wherein said look-up table of normals contains predefined normalized normals, and wherein each of said normals is represented by a single index into said look-up table of predefined normalized normals, said index having at least one characteristic selected from the group consisting of (i) said index includes bits of index representation comprising rectilinear representation sign bits of a normal to be represented, (ii) said index includes at least one bit specifying possible foldings of an absolute magnitude of a rectilinear representation of the normal to be represented by at least one folding plane x=y, x=z, y=z such that a folded normal is ensured to be on a known side of said folding plane, (iii) said index includes bits representing longitude information and latitude information of said normal, (iv) said index is defined to include bits of octant information, bits of sextant information, and additional fields of information about longitude and latitude of the folded normal, (v) said index includes bits representing longitude information and latitude information of said normal, and further includes bits of octant information, bits of sextant information, and additional fields of information about longitude and latitude of the folded normal, (vi) said index is defined to include three-bits of octant information, three-bits of sextant information, and two additional fields of information about longitude and latitude of the folded normal, and (vii) said index includes bits representing longitude information and latitude information of said normal, and further includes three bits of octant information, three-bits of sextant information, and two additional fields of information about longitude and latitude of the folded normal.
Claim 17
Independent Claim
71 words
The method of any of claims 11 to 16, wherein said data stream to be decompressed results from said objects having been represented as three-dimensional triangular data defining a plurality of triangles having vertices, which data were converted into linear format defining a generalized triangular mesh, individual ones of said surface characteristics having been quantized, and variable length compression having been applied to a difference between sequential ones said surface characteristics.
References Cited (Backward Citations)
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