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公开(公告)号：GB2215961A
公开(公告)日：1989-09-27
申请号：GB8806880
申请日：1988-03-23
Applicant: BENCHMARK TECHNOLOGIES
Inventor： TREVETT NEIL FRANCIS , WILSON MALCOLM ERIC , LLOYD SARAH JANE
Abstract: A line having two directional components and a given length is clipped to display only a predetermined segment of the line by initializing any of a multiplier accumulator's output registers 410, 412, 414 with a predetermined intial value; loading a first input register 402 of a multiplier accumulator with the value of one component of the line; loading a second input register 404 of the multiplier accumulator with the value of the reciprocal of the other component of the line; causing the multiplier accumulator to multiply 406 the values in its first and second input registers; repeatedly adding the fractional part of the multiply to the first output register 410 while adding the overflow of the first output register in a second output register 412; repeatedly adding the integer part of the result of the multiply to the second register 412; and, drawing a point on a display device whenever the value in the second output register changes. The reciprocals for register 404 may come from a look-up table (502, fig 5). This method uses simple hardware, avoids divide operations and addresses the "Subset line" problem.
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公开(公告)号：GB2215960A
公开(公告)日：1989-09-27
申请号：GB8806879
申请日：1988-03-23
Applicant: BENCHMARK TECHNOLOGIES
Inventor： TREVETT NEIL FRANCIS , WILSON MALCOLM ERIC , LLOYD SARAH JANE
Abstract: A method of linear interpolation over a line having a given length comprising the steps of initializing the multiplier accumulators output registers with predetermined initial values 410, 412 [e.g. with the initial rounding value and the starting value for one of the coordinates (e.g. Y), respectively]; loading a first input register 402 of the multiplier accumulator with a value equal to the incremental change (e.g. DELTA Y=5) in the output value over the length of the line; loading a second input register 404 of the multiplier accumulator with a value (1/N) equal to the reciprocal of the length of the line (N); causing the multiplier 406 to multiply the values (eg DELTA Y and 1/N) at its first and second inputs; accumulating the fractional part of the result of the multiplication in a first output register 410; accumulating the interger part of the result of the multiplication added with the overflow of the first output register in a second output register, 412, whereby and accumulated result is formed. The overflow is accumulated in a third output register, 414, and overflows to the integral register. For Gouraud shading of a line, one of the input registers is loaded with colour change along a line and the other with reciprocal of line length. An output register, 412, is initialised with a start colour.
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公开(公告)号：GB2214676A
公开(公告)日：1989-09-06
申请号：GB8801125
申请日：1988-01-19
Applicant: BENCHMARK TECHNOLOGIES
Inventor： TREVETT NEIL FRANCIS , LLOYD SARAH JANE , WILSON MALCOLM ERIC
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