EP0144924A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
True-perspective texture/shading processor
Assignee: General Electric Co
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Filing: 1984-11-29
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Granted: —
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Expires: 2004-11-29
Abstract
Abstract A low cost, true-perspective texture/shading processor (16) for a raster graphics display is based on a mathematical model which defines modulations globally over the entire simulated, visual environment. The mathematical model uses planes defined in three-dimensional space to define the texture modulation. These texture planes are all orthogonal to a single gradient in a flat reference plane and may cut across any number of faces. The texture/shading processor is used in a computer image generator of the type wherein computations are performed in sequence by a plurality of functional groups. The first group (11) manages a visual data base (10) and transfers data to the active environment storage of the second group (12). The first group determines the position of the view point and any moving models in a common coordinate system and generates the trigonometric coefficients required for perspective transformation. The second group reduces the three-dimensional description of the environment supplied by the first group to a two-dimensional description, makes perspective transformation of data into coordinates of a view window and assigns a priority to each surface of the computed scene. The third group reduces the two-dimensional description generated by the second group to a scan line by generating edge data (14) to locate where edges cross the scan line and responds to the assigned priorities (15) to eliminate hidden surfaces and generates the video for display (17) including edge smoothing, shading and texture effects. The second group further includes a face modulation processore (13) for computing data describing each texture and shading model and data describing the plane of each textured or shaded face. The texture/shading processor (16) is in the third group and is responsive to initialization data from the first group and the data computed by the face modulation processor for computing texture and shading modulation signals.
Inventors
- 👤 Edward Mitford Sims
- 👤 Jimmy Everett Chandler
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 08:17
CPC Classifications
G; G09; G09B; G09B9/00; G09B9/02; G09B9/08; G09B9/30; G09B9/301; G06; G06T; G06T15/00; G06T15/50; G06T15/80
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
268 words
In a computer image generator of the type wherein computations are performed in sequence by a plurality of functional groups including a first group which manages a visual data base and transfers data to the active environment storage of a second group, said first group determining the position of the viewpoint and any moving models in a common coordinate system and generating trigonometric coefficients required for perspective transformation, said second group which reduces a three-dimensional description of the environment supplied by said first group to a two-dimensional description, makes perspective transformation of data into coordinates of aview window and assigns a priority to each surface of the computed scene, and a third group which reduces the two-dimensional description generated by said second group to a scan line by generating edge data to locate where edges cross the scan line and responds to the assigned priorities to eliminate hidden surfaces and generates the video for display including edge smoothing, shading and texture effects, the improvement comprising texture/shading processing means which defines modulations globally over the entire simulated, visual environment, said texture/shading processing means comprising: face modulation processing means in said second group for computing data describing each texture and shading model and data describing the plane of each textureed or shaded face; and texture/shading generator means in said third group responsive to initialization data from said first group and the data computed by said face modulation processing means for computing texture and shading modulation signals based on a mathematical model that uses parallel planes defined in three-dimensional space to divide any number of faces into texture and shading stripes.
Claim 2
Dependent Claim
268 words
In a computer image generator of the type wherein computations are performed in sequence by a plurality of functional groups including a first group which manages a visual data base and transfers data to the active environment storage of a second group, said first group determining the position of the viewpoint and any moving models in a common coordinate system and generating trigonometric coefficients required for perspective transformation, said second group which reduces a three-dimensional description of the environment supplied by said first group to a two-dimensional description, makes perspective transformation of data into coordinates of aview window and assigns a priority to each surface of the computed scene, and a third group which reduces the two-dimensional description generated by said second group to a scan line by generating edge data to locate where edges cross the scan line and responds to the assigned priorities to eliminate hidden surfaces and generates the video for display including edge smoothing, shading and texture effects, the improvement comprising texture/shading processing means which defines modulations globally over the entire simulated, visual environment, said texture/shading processing means comprising: face modulation processing means in said second group for computing data describing each texture and shading model and data describing the plane of each textureed or shaded face; and texture/shading generator means in said third group responsive to initialization data from said first group and the data computed by said face modulation processing means for computing texture and shading modulation signals based on a mathematical model that uses parallel planes defined in three-dimensional space to divide any number of faces into texture and shading stripes.
Claim 3
Dependent Claim
272 words
The improved computer image generator as recited in claim 1 wherein said texture/shading generator means comprises: pattern memory means connected to said face modulation processing means for storing the data describing each texture and shading model; face memory means connected to said face modulation processing means for storing the data describing the plane of each textured or shaded face; edge memory means for storing edge data; data register means connected to said first group for storing the line and element number of the pixel at the orthogonal to the view plane; edge crossing control means connected to said edge memory means and said data register means for computing the relative line number and element number; first distance calculator means connected to said face memory means and said edge crossing control means and responsive to data addressed by said edge memory means for computing the distance to each pixel group; first base number calculator means connected to said pattern memory means, said edge crossing control means and said first distance calculator means and responsive to data addressed by said face memory means and read out of said pattern memory means for mapping each pixel group into texture stripe numbers; texture computer means connected to said first base number calculator means for storing texture modulation maps and computing blending and smoothing of the maps selected by the base number calculation; and first shading computer means connected to said first base number calculator means and said texture computer means for computing by linear interpolation the shading modulation based on the base number calculation and selecting shading, texture or no modulation to the video for display.
Claim 4
Dependent Claim
210 words
The improved computer image generator .as recited in claim 2 wherein said first base number calculator means and said texture computer means are replicated three times,-one for each of three gradients defining a parallel series of planes of equal intensity, and wherein said edge memory means further stores hold flags indicating that data for a current face to be retained for shading computations in the next pixel group, said improved computer image generator further comprising: second distance calculator means connected to said face memory means and said edge crossing control means and responsive to said hold flags and data addressed by said edge memory means for computing the distance to the next pixel group; second base number calculator means connected to said pattern memory means, said edge crossing control means and said second distance calculator means and responsive to said hold flags and data addressed by said face memory means and read out of said pattern memory means for computing the shading modulation of the next pixel group; and second shading computer means connected to said second base number calculator means for computing by linear interpolation the shading modulation based on the output of said second base number calculator means for modulating the video display of the next pixel group.
Claim 5
Dependent Claim
62 words
The improved computer image generator as recited in claim 2 wherein said first distance calculator means includes means for generating a series expansion reciprocal common denominator and said first base number calculator means includes means for calculating multiple pattern base numbers by multiplying said series expansion reciprocal common denominator distance term with global numerator terms which define texture pattern orientations and spacing.
Claim 6
Dependent Claim
100 words
The improved computer image generator as recited in claim 3 wherein said first distance calculator means includes means for generating a first series expansion reciprocal common denominator, said first base number calculator means includes means for calculating multiple pattern base numbers by multiplying said first series expansion reciprocal common denominator distance term with global numerator terms which define texture pattern orientations and spacing, said second distance calculator means includes means for generating a second series expansion reciprocal denominator term, and said second base number calculator means includes means for multiplying said second series expansion reciprocal denominator by a single numerator.
Claim 7
Dependent Claim
27 words
The improved computer image generator as recited in claim 2 wherein said texture computer means includes means for storing multiple texture maps with precalculated levels of detail.
Claim 8
Dependent Claim
27 words
The improved computer image generator as recited in claim 6 wherein said texture computer means further includes means for smooth blending of the map levels of detail.
Claim 9
Dependent Claim
48 words
The improved computer image generator as recited in claim 7 wherein said texture computer means further includes means for calculating texture edge crossings and generating texture edge smoothing of crossing stripes by using only the left pattern corner value and two pattern gradients in the display view plane.
Claim 10
Dependent Claim
32 words
The improved computer image generator as recited in claim 8 wherein said first shading computer means includes means for summing multiplicative texture patterns into a combined modulation of differning spacing and orientations.
Claim 11
Dependent Claim
33 words
The improved computer image generator as recited in claim 9 wherein said first shading computer means further includes translation map means for converting said texture combined modulations into a clustered or randomized redefinition.
Claim 12
Dependent Claim
50 words
The improved computer image generator as recited in claim 10 wherein said first shading computer means further comprises means for the multiplicative shading or texture modulation of a face red, blue or green color component in any combination so as to achieve the monochromatic or color modualtion of said face.
References Cited (Backward Citations)
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