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Author Topic: Seeking best ellipse fill function. (For everyone's sake.)  (Read 22380 times)

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Offline bplus

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Re: Seeking best ellipse fill function. (For everyone's sake.)
« Reply #30 on: February 10, 2019, 12:01:16 pm »
Quote from: STxAxTIC on February 10, 2019, 11:59:36 am
Your attention to detail is indispensible plus! I wonder it the algorithm can be torn apart to find out why that happens... The thing seems to be *so* optimized that it became fragile. As soon as I get near a PC I will join your efforts...


Probably I am starting to become PIA.

I am next going to submit CircleFill to same test.
« Last Edit: February 10, 2019, 12:03:15 pm by bplus »
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Offline Pete

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Re: Seeking best ellipse fill function. (For everyone's sake.)
« Reply #31 on: February 10, 2019, 12:18:28 pm »
Don't give up. I don't know a single person who gets a program to run correctly from the first time out of the gate, unless it's that Hello World guru.

I don't see an obvious pattern in the results you posted, which means something in the algorithm is crunching numbers with probably some decimal off in the wrong direction.

BTW- you probably meant PITA, instead of PIA, you PITA!

Pete :D
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Offline bplus

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Re: Seeking best ellipse fill function. (For everyone's sake.)
« Reply #32 on: February 10, 2019, 12:22:22 pm »
Well hurray, CircleFill still holds up!
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Offline Pete

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Re: Seeking best ellipse fill function. (For everyone's sake.)
« Reply #33 on: February 10, 2019, 03:26:53 pm »
Here's my fix to the 1 to 400 problem. Hey, check it carefully, as I flipped through it fast. No patience for this crap, sorry.

Anyway, if it works it works because it simply checks the boundaries set byt the fist line statements and doesn't let the second set of line statements overlap them, which was causing the initial problem at radius entries like 45, 67, etc.

Code: QB64: [Select]
  1. _TITLE "Ellipsefill from Steve"
  2. SCREEN _NEWIMAGE(1000, 700, 32)
  3. _SCREENMOVE 180, 20
  4. 'B+ 2019-02-10 resave this code to
  5. 'just test this code for proper filling without overlap, timed tests are else where
  6.  
  7. FOR i = 1 TO 400 'draw ellipse at various heights
  8.     CLS
  9.     PRINT "b Radius"; i; " Press any to get to 400, <backspace> to go back one, <esc> for next test."
  10.     EllipseFill 500, 350, 400, i, _RGBA(255, 255, 255, 40)
  11.     k$ = ""
  12.     WHILE LEN(k$) = 0: k$ = INKEY$: WEND
  13.     IF k$ = CHR$(8) THEN i = i - 2
  14.     IF k$ = CHR$(27) THEN EXIT FOR
  16.  
  18. WHILE _KEYDOWN(32) = 0 'check all sorts random stuff
  19.     EllipseFill RND * 1000, RND * 700, RND * 100, RND * 100, _RGBA32(255 * RND, 255 * RND, 255 * RND, 100 * RND)
  20.     _LIMIT 1
  22.  
  23. ' with Steve's EllipseFill, who needs CircleFill? fix for 0 radii 2019-02-05
  24. ' Is this fast enough for general circle fill (June 2018):  https://www.qb64.org/forum/index.php?topic=298.msg1942#msg1942
  25. '  EllipseFill SMcNeill (Nov 3, 2018) https://www.qb64.org/forum/index.php?topic=755.msg6506#msg6506
  26. SUB EllipseFill (cx AS INTEGER, cy AS INTEGER, rx AS INTEGER, ry AS INTEGER, c AS _UNSIGNED LONG)
  29.  
  31. DIM sx AS LONG, sy AS LONG
  33.  
  34. IF rx = 0 OR ry = 0 THEN EXIT SUB 'nothing to draw, B+ added this to avoid errors when b was 0
  35.  
  36. a = 2 * rx * rx
  37. b = 2 * ry * ry
  38. x = rx
  39. xx = ry * ry * (1 - 2 * rx)
  40. yy = rx * rx
  41. sx = b * rx
  42.  
  43. DO WHILE sx >= sy 'no = ? , nope that didn't help
  44.     LINE (cx - x, cy - y)-(cx + x, cy - y), c, BF
  45.     IF y <> 0 THEN LINE (cx - x, cy + y)-(cx + x, cy + y), c, BF
  46.     y = y + 1
  47.     sy = sy + a
  48.     e = e + yy
  49.     yy = yy + a
  50.  
  51.     IF (e + e + xx) > 0 THEN 'add = ? nope no fix
  52.         x = x - 1
  53.         sx = sx - b
  54.         e = e + xx
  55.         xx = xx + b
  56.     END IF
  58. oldy = y ' Pete's fix
  59. x = 0
  60. y = ry
  61. xx = rx * ry
  62.  
  63. yy = rx * rx * (1 - 2 * ry)
  64. e = 0
  65. sx = 0
  66. sy = a * ry
  67.  
  69.     LINE (cx - x, cy - y)-(cx + x, cy - y), c, BF
  70.     LINE (cx - x, cy + y)-(cx + x, cy + y), c, BF
  71.     DO
  72.         x = x + 1
  73.         sx = sx + b
  74.         e = e + xx
  75.         xx = xx + b
  76.     LOOP UNTIL (e + e + yy) > 0 'add = ? nope no fix
  77.     y = y - 1
  78.     sy = sy - a
  79.     e = e + yy
  80.     yy = yy + a
  81. LOOP UNTIL y < oldy
  82.  
  84.  
  85.  
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Offline bplus

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Re: Seeking best ellipse fill function. (For everyone's sake.)
« Reply #34 on: February 10, 2019, 03:53:06 pm »
Nice Pete! I will run time tests on this fix.
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Offline Pete

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Re: Seeking best ellipse fill function. (For everyone's sake.)
« Reply #35 on: February 10, 2019, 03:58:18 pm »
Hey did you guys find out that different ways of expressing equations are calculated faster? Case in point, I tend to own code, and I started changing things like - r + r to - 2 * r. I was about to change things like ry * ry to ry ^2, but then I thought I'd ask here first. If - r + r, or whatever it was, would run faster than the 2 * r I changed it to, then by all means, change it back before you do the speed tests. That way, you have apples to apples, should it make a difference.

Pete
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Offline bplus

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Re: Seeking best ellipse fill function. (For everyone's sake.)
« Reply #36 on: February 10, 2019, 04:47:51 pm »
OK they are still running neck and neck, the gold standard running a very large radius circle 10000 time versus EllipseFill now with latest fix from Pete in a timed test. So the Ellipse fill can be used both for CircleFill and EllipseFill when ellipse needed has axis parallel to x, y axis, otherwise use TiltedEllipseFill for angular Ellipse fills.
« Last Edit: February 10, 2019, 04:51:32 pm by bplus »
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Offline Pete

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Re: Seeking best ellipse fill function. (For everyone's sake.)
« Reply #37 on: February 10, 2019, 04:51:55 pm »
Did you check what I posted above about switching up some of the math calcs? I don't want such a change to impede the speed.

Pete
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Offline bplus

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Re: Seeking best ellipse fill function. (For everyone's sake.)
« Reply #38 on: February 10, 2019, 04:53:37 pm »
Quote from: Pete on February 10, 2019, 04:51:55 pm
Did you check what I posted above about switching up some of the math calcs? I don't want such a change to impede the speed.

Pete

Yes, nothing with the math was changed that I could see.
Here is the test code for time:
Code: QB64: [Select]
  1. _TITLE "Steves EllipseFill (right) vrs gold standard CircleFill (left), 2 tests take about 17 secs each after you press enter."
  2.  
  3. DEFINT A-Z
  4. SCREEN _NEWIMAGE(1220, 680, 32)
  5. _SCREENMOVE 100, 20
  7.  
  8. EllipseFill 915, 305, 300, 300, _RGBA32(0, 100, 0, 40)
  9. EllipseFill 915, 305, 300, 300, _RGBA32(0, 100, 0, 40)
  10. INPUT "EllipseFill (fel) overlap test, press enter to continue "; wate$
  11. LINE (0, 0)-(600, 20), _RGB32(0, 0, 0), BF
  12. start## = TIMER
  13. FOR i = 1 TO 10000
  14.     EllipseFill 915, 305, 300, 300, _RGBA32(0, 100, 0, 100)
  16. EllipseTime## = TIMER - start##
  17. _PRINTSTRING (800, 615), "Time for 10000 EllipseFills:" + STR$(EllipseTime##)
  18.  
  19.  
  20. ' ==================================================== compare to the old gold standard
  21.  
  22. CircleFill 305, 305, 300, _RGBA32(0, 100, 0, 40)
  23. CircleFill 305, 305, 300, _RGBA32(0, 100, 0, 40)
  24. LOCATE 1, 1: INPUT "CircleFill overlap test, press enter to continue "; wate$
  25. LINE (0, 0)-(600, 20), _RGB32(0, 0, 0), BF
  26.  
  27. start## = TIMER
  28. FOR i = 1 TO 10000
  29.     CircleFill 305, 305, 300, _RGBA32(0, 100, 0, 100)
  31. OldCircleTime## = TIMER - start##
  32. _PRINTSTRING (200, 615), "Time for 10000 Circle Fills:" + STR$(OldCircleTime##)
  33.  
  34. 'old circle fill
  35. SUB CircleFill (CX AS INTEGER, CY AS INTEGER, R AS INTEGER, C AS _UNSIGNED LONG)
  36.     DIM Radius AS INTEGER, RadiusError AS INTEGER
  37.     DIM X AS INTEGER, Y AS INTEGER
  38.  
  39.     Radius = ABS(R)
  40.     RadiusError = -Radius
  41.     X = Radius
  42.     Y = 0
  43.  
  44.     IF Radius = 0 THEN PSET (CX, CY), C: EXIT SUB
  45.  
  46.     ' Draw the middle span here so we don't draw it twice in the main loop,
  47.     ' which would be a problem with blending turned on.
  48.     LINE (CX - X, CY)-(CX + X, CY), C, BF
  49.  
  50.     WHILE X > Y
  51.         RadiusError = RadiusError + Y * 2 + 1
  52.         IF RadiusError >= 0 THEN
  53.             IF X <> Y + 1 THEN
  54.                 LINE (CX - Y, CY - X)-(CX + Y, CY - X), C, BF
  55.                 LINE (CX - Y, CY + X)-(CX + Y, CY + X), C, BF
  56.             END IF
  57.             X = X - 1
  58.             RadiusError = RadiusError - X * 2
  59.         END IF
  60.         Y = Y + 1
  61.         LINE (CX - X, CY - Y)-(CX + X, CY - Y), C, BF
  62.         LINE (CX - X, CY + Y)-(CX + X, CY + Y), C, BF
  63.     WEND
  64.  
  66.  
  67. ' now with Pete's fix for overlap 2019-02-10
  68. ' with Steve's EllipseFill, who needs CircleFill? fix for 0 radii 2019-02-05
  69. ' Is this fast enough for general circle fill (June 2018):  https://www.qb64.org/forum/index.php?topic=298.msg1942#msg1942
  70. '  EllipseFill SMcNeill (Nov 3, 2018) https://www.qb64.org/forum/index.php?topic=755.msg6506#msg6506
  71. SUB EllipseFill (cx AS INTEGER, cy AS INTEGER, rx AS INTEGER, ry AS INTEGER, c AS _UNSIGNED LONG)
  72.     DIM a AS LONG, b AS LONG
  73.     DIM x AS LONG, y AS LONG
  74.     DIM xx AS LONG, yy AS LONG
  75.     DIM sx AS LONG, sy AS LONG
  76.     DIM e AS LONG
  77.  
  78.     IF rx = 0 OR ry = 0 THEN EXIT SUB 'nothing to draw, B+ added this to avoid errors when b was 0
  79.  
  80.     a = 2 * rx * rx
  81.     b = 2 * ry * ry
  82.     x = rx
  83.     xx = ry * ry * (1 - rx - rx)
  84.     yy = rx * rx
  85.     sx = b * rx
  86.  
  87.     DO WHILE sx >= sy 'no = ? , nope that didn't help
  88.         LINE (cx - x, cy - y)-(cx + x, cy - y), c, BF
  89.         IF y <> 0 THEN LINE (cx - x, cy + y)-(cx + x, cy + y), c, BF
  90.  
  91.         y = y + 1
  92.         sy = sy + a
  93.         e = e + yy
  94.         yy = yy + a
  95.  
  96.         IF (e + e + xx) > 0 THEN 'add = ? nope no fix
  97.             x = x - 1
  98.             sx = sx - b
  99.             e = e + xx
  100.             xx = xx + b
  101.         END IF
  102.     LOOP
  103.     oldy = y ' Pete's fix
  104.     x = 0
  105.     y = ry
  106.     xx = rx * ry
  107.     yy = rx * rx * (1 - ry - ry)
  108.     e = 0
  109.     sx = 0
  110.     sy = a * ry
  111.  
  112.     DO '   Pete's fix eliminate >   WHILE sx <= sy ' no  =  ? fixed once but mostly no fix
  113.         LINE (cx - x, cy - y)-(cx + x, cy - y), c, BF
  114.         LINE (cx - x, cy + y)-(cx + x, cy + y), c, BF
  115.  
  116.         DO
  117.             x = x + 1
  118.             sx = sx + b
  119.             e = e + xx
  120.             xx = xx + b
  121.         LOOP UNTIL (e + e + yy) > 0 'add = ? nope no fix
  122.  
  123.         y = y - 1
  124.         sy = sy - a
  125.         e = e + yy
  126.         yy = yy + a
  127.  
  128.     LOOP UNTIL y < oldy ' pete's fix
  129.  
  131.  
  132.  
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Offline Pete

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Re: Seeking best ellipse fill function. (For everyone's sake.)
« Reply #39 on: February 10, 2019, 05:16:27 pm »
No, reread it. I mean I changed a couple of lines from r + r to 2 * r. I'll post this one with all of the changes I can find to condense the math using powers, * 2, etc. Maybe it runs faster one way or the other, but I just like the math better with 2*, ^2, etc. If it makes no speed difference, it doesn't matter how you want to go about posting the finished product. Just know I changed 2 lines in the one you tested and you can change them back, for conformity sake, if you wish. Either way, yes, it produces the exact same math results.

So here is one I completely converted, unless I missed something.

Code: QB64: [Select]
  1. _TITLE "Ellipsefill from Steve"
  2. SCREEN _NEWIMAGE(1000, 700, 32)
  3. _SCREENMOVE 180, 20
  4. ' Pete changed math operations so r * r is now R^2, r + r is 2 * r, etc.
  5. 'B+ 2019-02-10 resave this code to
  6. 'just test this code for proper filling without overlap, timed tests are else where
  7.  
  8. FOR i = 1 TO 400 'draw ellipse at various heights
  9.     CLS
  10.     PRINT "b Radius"; i; " Press any to get to 400, <backspace> to go back one, <esc> for next test."
  11.     EllipseFill 500, 350, 400, i, _RGBA(255, 255, 255, 40)
  12.     k$ = ""
  13.     WHILE LEN(k$) = 0: k$ = INKEY$: WEND
  14.     IF k$ = CHR$(8) THEN i = i - 2
  15.     IF k$ = CHR$(27) THEN EXIT FOR
  17.  
  19. WHILE _KEYDOWN(32) = 0 'check all sorts random stuff
  20.     EllipseFill RND * 1000, RND * 700, RND * 100, RND * 100, _RGBA32(255 * RND, 255 * RND, 255 * RND, 100 * RND)
  21.     _LIMIT 1
  23.  
  24. ' with Steve's EllipseFill, who needs CircleFill? fix for 0 radii 2019-02-05
  25. ' Is this fast enough for general circle fill (June 2018):  https://www.qb64.org/forum/index.php?topic=298.msg1942#msg1942
  26. '  EllipseFill SMcNeill (Nov 3, 2018) https://www.qb64.org/forum/index.php?topic=755.msg6506#msg6506
  27. SUB EllipseFill (cx AS INTEGER, cy AS INTEGER, rx AS INTEGER, ry AS INTEGER, c AS _UNSIGNED LONG)
  30.  
  32. DIM sx AS LONG, sy AS LONG
  34.  
  35. IF rx = 0 OR ry = 0 THEN EXIT SUB 'nothing to draw, B+ added this to avoid errors when b was 0
  36.  
  37. a = 2 * rx ^ 2
  38. b = 2 * ry ^ 2
  39. x = rx
  40. xx = ry ^ 2 * (1 - 2 * rx)
  41. yy = rx ^ 2
  42. sx = b * rx
  43.  
  44. DO WHILE sx >= sy 'no = ? , nope that didn't help
  45.     LINE (cx - x, cy - y)-(cx + x, cy - y), c, BF
  46.     IF y <> 0 THEN LINE (cx - x, cy + y)-(cx + x, cy + y), c, BF
  47.     y = y + 1
  48.     sy = sy + a
  49.     e = e + yy
  50.     yy = yy + a
  51.  
  52.     IF (2 * e + xx) > 0 THEN 'add = ? nope no fix
  53.         x = x - 1
  54.         sx = sx - b
  55.         e = e + xx
  56.         xx = xx + b
  57.     END IF
  59.  
  60. oldy = y ' Pete's fix
  61. x = 0
  62. y = ry
  63. xx = rx * ry
  64.  
  65. yy = rx ^ 2 * (1 - 2 * ry)
  66. e = 0
  67. sx = 0
  68. sy = a * ry
  69.  
  71.     LINE (cx - x, cy - y)-(cx + x, cy - y), c, BF
  72.     LINE (cx - x, cy + y)-(cx + x, cy + y), c, BF
  73.     DO
  74.         x = x + 1
  75.         sx = sx + b
  76.         e = e + xx
  77.         xx = xx + b
  78.     LOOP UNTIL (2 * e + yy) > 0 'add = ? nope no fix
  79.     y = y - 1
  80.     sy = sy - a
  81.     e = e + yy
  82.     yy = yy + a
  83. LOOP UNTIL y < oldy ' Pete's fix applied here.
  84.  
  86.  
« Last Edit: February 10, 2019, 05:35:07 pm by Pete »
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Offline SMcNeill

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Re: Seeking best ellipse fill function. (For everyone's sake.)
« Reply #40 on: February 10, 2019, 06:18:28 pm »
R + R is faster than 2 * R
R * R is faster than R ^ 2

Certain operations have more overhead than others.  If you’re going to optimize for speed, choose the operator with the fastest performance.  ;)
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Offline Pete

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Re: Seeking best ellipse fill function. (For everyone's sake.)
« Reply #41 on: February 10, 2019, 06:25:40 pm »
That's what I wanted to know.

So, my fix applied with the fastest math method according to Steve would be...

Code: QB64: [Select]
  1. _TITLE "Ellipsefill from Steve"
  2. SCREEN _NEWIMAGE(1000, 700, 32)
  3. _SCREENMOVE 180, 20
  4. 'B+ 2019-02-10 resave this code to
  5. 'just test this code for proper filling without overlap, timed tests are else where
  6.  
  7. FOR i = 1 TO 400 'draw ellipse at various heights
  8.     CLS
  9.     PRINT "b Radius"; i; " Press any to get to 400, <backspace> to go back one, <esc> for next test."
  10.     EllipseFill 500, 350, 400, i, _RGBA(255, 255, 255, 40)
  11.     k$ = ""
  12.     WHILE LEN(k$) = 0: k$ = INKEY$: WEND
  13.     IF k$ = CHR$(8) THEN i = i - 2
  14.     IF k$ = CHR$(27) THEN EXIT FOR
  16.  
  18. WHILE _KEYDOWN(32) = 0 'check all sorts random stuff
  19.     EllipseFill RND * 1000, RND * 700, RND * 100, RND * 100, _RGBA32(255 * RND, 255 * RND, 255 * RND, 100 * RND)
  20.     _LIMIT 1
  22.  
  23. ' with Steve's EllipseFill, who needs CircleFill? fix for 0 radii 2019-02-05
  24. ' Is this fast enough for general circle fill (June 2018):  https://www.qb64.org/forum/index.php?topic=298.msg1942#msg1942
  25. '  EllipseFill SMcNeill (Nov 3, 2018) https://www.qb64.org/forum/index.php?topic=755.msg6506#msg6506
  26. SUB EllipseFill (cx AS INTEGER, cy AS INTEGER, rx AS INTEGER, ry AS INTEGER, c AS _UNSIGNED LONG)
  29.  
  31. DIM sx AS LONG, sy AS LONG
  33.  
  34. IF rx = 0 OR ry = 0 THEN EXIT SUB 'nothing to draw, B+ added this to avoid errors when b was 0
  35.  
  36. a = 2 * rx * rx
  37. b = 2 * ry * ry
  38. x = rx
  39. xx = ry * ry * (1 - rx - rx)
  40. yy = rx * rx
  41. sx = b * rx
  42.  
  43. DO WHILE sx >= sy
  44.     LINE (cx - x, cy - y)-(cx + x, cy - y), c, BF
  45.     IF y <> 0 THEN LINE (cx - x, cy + y)-(cx + x, cy + y), c, BF
  46.     y = y + 1
  47.     sy = sy + a
  48.     e = e + yy
  49.     yy = yy + a
  50.  
  51.     IF (e + e + xx) > 0 THEN
  52.         x = x - 1
  53.         sx = sx - b
  54.         e = e + xx
  55.         xx = xx + b
  56.     END IF
  58. oldy = y ' Pete's fix. Get the last fill position.
  59. x = 0
  60. y = ry
  61. xx = rx * ry
  62.  
  63. yy = rx * rx * (1 - ry - ry)
  64. e = 0
  65. sx = 0
  66. sy = a * ry
  67.  
  69.     LINE (cx - x, cy - y)-(cx + x, cy - y), c, BF
  70.     LINE (cx - x, cy + y)-(cx + x, cy + y), c, BF
  71.     DO
  72.         x = x + 1
  73.         sx = sx + b
  74.         e = e + xx
  75.         xx = xx + b
  76.     LOOP UNTIL (e + e + yy) > 0
  77.     y = y - 1
  78.     sy = sy - a
  79.     e = e + yy
  80.     yy = yy + a
  81. LOOP UNTIL y < oldy ' Pete's fix applied here.
  82.  
  84.  
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Offline bplus

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Re: Seeking best ellipse fill function. (For everyone's sake.)
« Reply #42 on: February 10, 2019, 06:34:06 pm »
Quote from: Pete on February 10, 2019, 06:25:40 pm
That's what I wanted to know.

So, my fix applied with the fastest math method according to Steve would be...

Code: QB64: [Select]
  1. _TITLE "Ellipsefill from Steve"
  2. SCREEN _NEWIMAGE(1000, 700, 32)
  3. _SCREENMOVE 180, 20
  4. 'B+ 2019-02-10 resave this code to
  5. 'just test this code for proper filling without overlap, timed tests are else where
  6.  
  7. FOR i = 1 TO 400 'draw ellipse at various heights
  8.     CLS
  9.     PRINT "b Radius"; i; " Press any to get to 400, <backspace> to go back one, <esc> for next test."
  10.     EllipseFill 500, 350, 400, i, _RGBA(255, 255, 255, 40)
  11.     k$ = ""
  12.     WHILE LEN(k$) = 0: k$ = INKEY$: WEND
  13.     IF k$ = CHR$(8) THEN i = i - 2
  14.     IF k$ = CHR$(27) THEN EXIT FOR
  16.  
  18. WHILE _KEYDOWN(32) = 0 'check all sorts random stuff
  19.     EllipseFill RND * 1000, RND * 700, RND * 100, RND * 100, _RGBA32(255 * RND, 255 * RND, 255 * RND, 100 * RND)
  20.     _LIMIT 1
  22.  
  23. ' with Steve's EllipseFill, who needs CircleFill? fix for 0 radii 2019-02-05
  24. ' Is this fast enough for general circle fill (June 2018):  https://www.qb64.org/forum/index.php?topic=298.msg1942#msg1942
  25. '  EllipseFill SMcNeill (Nov 3, 2018) https://www.qb64.org/forum/index.php?topic=755.msg6506#msg6506
  26. SUB EllipseFill (cx AS INTEGER, cy AS INTEGER, rx AS INTEGER, ry AS INTEGER, c AS _UNSIGNED LONG)
  29.  
  31. DIM sx AS LONG, sy AS LONG
  33.  
  34. IF rx = 0 OR ry = 0 THEN EXIT SUB 'nothing to draw, B+ added this to avoid errors when b was 0
  35.  
  36. a = 2 * rx * rx
  37. b = 2 * ry * ry
  38. x = rx
  39. xx = ry * ry * (1 - rx - rx)
  40. yy = rx * rx
  41. sx = b * rx
  42.  
  43. DO WHILE sx >= sy
  44.     LINE (cx - x, cy - y)-(cx + x, cy - y), c, BF
  45.     IF y <> 0 THEN LINE (cx - x, cy + y)-(cx + x, cy + y), c, BF
  46.     y = y + 1
  47.     sy = sy + a
  48.     e = e + yy
  49.     yy = yy + a
  50.  
  51.     IF (e + e + xx) > 0 THEN
  52.         x = x - 1
  53.         sx = sx - b
  54.         e = e + xx
  55.         xx = xx + b
  56.     END IF
  58. oldy = y ' Pete's fix. Get the last fill position.
  59. x = 0
  60. y = ry
  61. xx = rx * ry
  62.  
  63. yy = rx * rx * (1 - ry - ry)
  64. e = 0
  65. sx = 0
  66. sy = a * ry
  67.  
  69.     LINE (cx - x, cy - y)-(cx + x, cy - y), c, BF
  70.     LINE (cx - x, cy + y)-(cx + x, cy + y), c, BF
  71.     DO
  72.         x = x + 1
  73.         sx = sx + b
  74.         e = e + xx
  75.         xx = xx + b
  76.     LOOP UNTIL (e + e + yy) > 0
  77.     y = y - 1
  78.     sy = sy - a
  79.     e = e + yy
  80.     yy = yy + a
  81. LOOP UNTIL y < oldy ' Pete's fix applied here.
  82.  
  84.  

And that is what I had in my timed tests and that is why I said Pete made no math changes.

we could change:
    a = 2 * rx * rx
    b = 2 * ry * ry

to a = rx*rx + rx*rx
    b = ry*ry + ry * ry
« Last Edit: February 10, 2019, 06:39:31 pm by bplus »
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Offline SMcNeill

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Re: Seeking best ellipse fill function. (For everyone's sake.)
« Reply #43 on: February 10, 2019, 06:43:47 pm »
Quote
    a = 2 * rx * rx

to a = rx*rx + rx*rx

You’ll just be slower....

You’re going from 2 multiplication operations to 2 multiplication operations AND an addition operation.

Maybe:  a1 = rx * rx: a = a1 + a1  (If lookup times are faster)
« Last Edit: February 10, 2019, 06:45:44 pm by SMcNeill »
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Offline bplus

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Re: Seeking best ellipse fill function. (For everyone's sake.)
« Reply #44 on: February 10, 2019, 06:48:18 pm »
Yep! Confirmed I changed it back.
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