Solids modelling generator

• US 4,730,261 A
• Filed: 04/06/1987
• Issued: 03/08/1988
• Est. Priority Date: 10/25/1983
• Status: Expired due to Fees

• Current Assignee: Ramtek Corp.
• Original Assignee: Ramtek Corp.
• Inventors: Smith, David M.
• Primary Examiner(s): Harkcom, Gary V.
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US07/035,630
• Time in Patent Office: 337 Days
• Field of Search: 364/512, 364/518, 364/521, 364/522, 364/900 MS, 340/724, 340/726, 340/747, 340/752, 340/729
• US Class Current: 345/422
• CPC Class Codes: G06F 12/0207 with multidimensional access, e.g. row/column, matrix
• CPC Class Codes: G06T 11/40 Filling a planar surface by adding surface attributes, e.g. colour or texture

Abstract

Surface fill using Bresenhem algorithm concepts can be adapted to handle the hidden surface and shading functions required in solids modelling. A first plurality of vector generators provides the surface fill function, a second plurality of vector generators provides the hidden surface function, and a third plurality of vector generators provides the shading function. All three pluralities of vector generators can be run in unison to increase the speed at which images of solids can be generated by a factor of 1000.

Claims

1. A graphics display apparatus for generating visual images of visible surfaces of geometric solids, wherein said geometric solids are defined by line segments which meet at vertices, and further wherein said vertices are defined in at least a three-dimensional coordinate system and by an intensity coordinate, comprising

visual display means for displaying an array of pixels;

refresh memory means coupled to the visual display means for storing the array of pixels, wherein each pixel of the array of pixels is stored at a designated address;

a first plurality of vector generator means, coupled to address the refresh memory means and responsive to a first set of coordinate values from selected ones of said vertices which define line segments of the geometric solids that oppose one another, for determining start, end, and intermediate points of parallel line segments which extend between the opposing line segments and which are parallel to a first dimensional axis of the three-dimensional coordinate system, wherein the first set of coordinate values correspond to a first set of specified coordinate dimensions of the three-dimensional coordinate system, and the start, end, and intermediate points are expressed in the first set of specified coordinate dimensions;

a second plurality of vector generator means, responsive to a second set of coordinate values from said selected ones of said vertices and to the start, end, and intermediate points of the parallel line segments, for determining coordinates values of the start, end, and intermediate points of said parallel line segments for the dimensional coordinates of the multi-dimensional coordinate system which were not included in the first set of dimensional coordinates, wherein the second set of coordinate values include coordinates which correspond to a second set of coordinate dimensions of the three-dimensional coordinate system, at least one coordinate dimension of which is different from that in the first set of specified coordinate dimensions;

means coupled to the first and second plurality of vector generator means, to the refresh memory means, and to the control means, for enabling the refresh memory means when points on visible surfaces are being identified by the first and second vector generator means;

a third plurality of vector generator means, coupled to the refresh memory means and to the determining means and responsive to the intensity and dimensional coordinate values from the selected ones of said vertices, for determining start, end, and intermediate intensity values of the parallel line segments and for supplying said intensity values to the refresh memory means; and

control means for coordinating the operation of the first, second, and third plurality of vector generator means and for addressing the refresh memory means and the determining means so that intensity values of the visible surface of the geometric solid are stored at the appropriate designated address of the refresh memory means.

2. The apparatus of claim 1, wherein the vector generator means in the pluralities of vector generator means are Bresenhem vector generators.

3. The apparatus of claim 1, wherein each of the first, second and third pluralities of vector generators comprise

first vector generator means responsive to the end points for one of the opposing line segments for determining intermediate points along the one opposing line segment;

second vector generator means responsive to the end points for a different one of the opposing line segments for determining intermediate points along the different one opposing line segment; and

third vector generator means responsive to the intermediate points determined by the first and second vector generator means for determining the intermediate points of the parallel line segments.

4. The apparatus of claim 3, wherein the first and second vector generator means of each of the first, second, and third pluralities of vector generator means, generate a new-start-found signal or a new-end-found whenever a start or an end point, respectively, whenever a new parallel line segment is identified, and further wherein the third vector generator means of each of the first, second, and third pluralities of vector generator means is responsive to a next-point signal and generates a next intermediate point of the new parallel line segment, the control means comprising

means coupled to each of the first, second, and third pluralities of vector generator means and responsive to the new-start-found signals for inhibiting the operation of the third vector generator means of each of the first, second, and third pluralities of vector generator means until the new-start-found or new-end-found signal is received from all of the first and second vector generator means of the first, second and third pluralities of vector generator means, and for thereafter issuing a next-point signal to the third vector generator means of each of the first, second, and third pluralities of vector generator means until the intermediate points are produced for the new parallel line segment.

5. The apparatus of claim 4, wherein the third vector generator means of each of the first, second, and third pluralities of vector control means respond to a load signal by accepting the start and end points of a next parallel line to be defined, and further wherein the control means includes

means responsive to the next-point signals for determining when each of the third vector generator means of each of the first, second and third pluralities of vector generator means has completed generating the intermediate points of the parallel line segment being defined and for thereafter supplying a load signal to the third vector generator means of each of the first, second, and third pluralities of vector generator means;

and

means for determining when all parallel line segments for the selected ones of said vertices have been defined for controlling the first and second vector generators of each of the first, second, and third pluralities of vector generators to process a next set of selected ones of said vertices.

6. The apparatus of claim 5, wherein the determining means includes

memory means addressed by the control means and the third vector generator means of the first plurality of vector generator means for storing depth information from the third vector generator means from the second plurality of vector generator means at the locations being addressed whenever the enable signal is generated, and for reading out depth information from the locations being addressed in the absence of the enable signal;

and

comparison means responsive to the depth information read out from the memory means for comparing the depth information against depth information currently being supplied by the third vector generator means of the second plurality of vector generator means and for providing the enable signal whenever the depth information currently being supplied by the third vector generator means exceeds the depth information from the memory means.

7. The apparatus of claim 6, wherein the control means further includes counter means, responsive to a start address and to the load signal for addressing the refresh memory means and the determining means, wherein the output of the counter means supplies a coordinate value which is common to points of the parallel line segment being defined by the first and second pluralities of vector generator means.

8. The apparatus of claim 1, wherein the vector generator means in the pluralities of vector generator means are differential drawing analyzers.