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Active Forums => QB64 Discussion => Topic started by: bplus on August 02, 2018, 03:28:49 pm

Title: _MAPTRIANGLE Distortion
Post by: bplus on August 02, 2018, 03:28:49 pm
Hi, in following code I think I am using the exact same dimensions and coordinates to map a cheese section to the shooter (when it's angle is zero) such that when you press a button the wedge shooter should appear cut directly from the cheese but the mapping is distorted the y radius of holes looks OK but the x dimension of holes are really stretched? I can't even tell if the image is coming from part of the corresponding wedge outline made in the cheese...

Maybe some fresh eyes can see the blunder I am making. I know I best not call it a bug, yet...
Code: QB64: [Select]
  1. _TITLE "Cheese Factory 2"
  2. 'QB64 X 64 version 1.2 20180228/86  from git b301f92
  3.  
  4. '2018-08-01 started from idea I had while trying to fix holes in Colbalt's cheese wedge shooter
  5. '2018-08-02 Make growCheese sub completely self contained
  6. ' fix shooter:
  7. '1. shooterX, shooterY must be in center of wedge
  8. '2. wedge needs rounded back as if cut from round cheese cake
  9.  
  10. CONST wW = 800
  11. CONST wH = 600
  12. CONST sR = 100
  13.  
  14. SCREEN _NEWIMAGE(wW, wH, 32)
  15. _SCREENMOVE 360, 60
  17. DIM SHARED shooterX, shooterY, shooterA
  18. shooterX = 400: shooterY = 300: shooterA = 0
  19.  
  20. DIM SHARED cheese&
  21. growCheese
  22. _PUTIMAGE , cheese&
  23.  
  24. 'OK on the cheese here is outline of where the shooter wedge will be mapped
  25. COLOR _RGB32(0, 0, 0)
  26. CIRCLE (wW / 2, wH / 2), sR + 1
  27. x = shooterX + sR * COS(shooterA)
  28. y = shooterY + sR * SIN(shooterA)
  29. x1 = shooterX + sR * COS(shooterA + _PI(5 / 6))
  30. y1 = shooterY + sR * SIN(shooterA + _PI(5 / 6))
  31. x2 = shooterX + sR * COS(shooterA + _PI(7 / 6))
  32. y2 = shooterY + sR * SIN(shooterA + _PI(7 / 6))
  33. LINE (x, y)-(x1, y1)
  34. LINE (x1, y1)-(x2, y2)
  35. LINE (x2, y2)-(x, y)
  36.  
  37. COLOR _RGB32(255, 255, 0)
  38. _PRINTSTRING (20, 20), "  Here is a sample of the cheese from which we are taking a wedge,  "
  39. _PRINTSTRING (20, 60), "  press any key to transfer cheese image to shooter surrounded by black square.  "
  40. _PRINTSTRING (20, 100), "  WHY IS THE IMAGE DISTORTED? a 1 to 1 ratio was used in _MAPTRIANGLE to same dimensions.  "
  41. _PRINTSTRING (20, 140), "  press left and right arrows to swing shooter around... escape quits.  "
  43.  
  45.     IF _KEYDOWN(19200) THEN _DELAY .05: shooterA = shooterA - _PI(5 / 360)
  46.     IF _KEYDOWN(19712) THEN _DELAY .05: shooterA = shooterA + _PI(5 / 360)
  47.     LINE (wW / 2 - sR - 5, wH / 2 - sR - 5)-STEP(2 * sR + 10, 2 * sR + 10), _RGB32(0, 0, 0), BF
  48.     drawShooter
  49.     _DISPLAY
  51.  
  52. SUB drawShooter ()
  53.     'first makeCheese and use cheese& image to build shooter image
  54.     'dim shared ShooterX, ShooterY, ShooterA, cheese&
  55.     x = shooterX + sR * COS(shooterA)
  56.     y = shooterY + sR * SIN(shooterA)
  57.     x1 = shooterX + sR * COS(shooterA + _PI(5 / 6))
  58.     y1 = shooterY + sR * SIN(shooterA + _PI(5 / 6))
  59.     cx = wW / 2 + sR * COS(0)
  60.     cy = wH / 2 + sR * SIN(0)
  61.     cx1 = cx + sR * COS(_PI(5 / 6))
  62.     cy1 = cy + sR * SIN(_PI(5 / 6))
  63.  
  64.     'take small traingles off cheese& image  and map them onto main screen at shooter position
  65.     stepper = _PI(1 / 72)
  66.     starter = _PI(5 / 6) + stepper
  67.     stopper = _PI(7 / 6)
  68.     FOR a = starter TO stopper STEP stepper
  69.         'one to one ratio of mapping
  70.         x2 = shooterX + sR * COS(shooterA + a)
  71.         y2 = shooterY + sR * SIN(shooterA + a)
  72.         cx2 = cx + sR * COS(a)
  73.         cy2 = cy + sR * SIN(a)
  74.         _MAPTRIANGLE (cx, cy)-(cx1, cy1)-(cx2, cy2), cheese& TO(x, y)-(x1, y1)-(x2, y2)
  75.         x1 = x2: y1 = y2: cx1 = cx2: cy1 = cy2
  76.     NEXT
  77.  
  78.     'check overlap:  not perfect but good enough!
  79.     x = shooterX + sR * COS(shooterA)
  80.     y = shooterY + sR * SIN(shooterA)
  81.     x1 = shooterX + sR * COS(shooterA + _PI(5 / 6))
  82.     y1 = shooterY + sR * SIN(shooterA + _PI(5 / 6))
  83.     x2 = shooterX + sR * COS(shooterA + _PI(7 / 6))
  84.     y2 = shooterY + sR * SIN(shooterA + _PI(7 / 6))
  85.     LINE (x, y)-(x1, y1), _RGB32(255, 255, 255)
  86.     LINE (x1, y1)-(x2, y2), _RGB32(255, 255, 255)
  87.     LINE (x2, y2)-(x, y), _RGB32(255, 255, 255)
  88.  
  90.  
  91.  
  92. SUB growCheese () 'make this more self contained than first version, all hole stuff just in here
  93.     curr& = _DEST
  94.     IF cheese& THEN _FREEIMAGE cheese&
  95.     cheese& = _NEWIMAGE(wW, wH, 32)
  96.     _DEST cheese&
  97.     nHoles = 300: maxHoleLife = 20: maxHoleRadius = 7: tfStart = 1
  98.     DIM hx(nHoles), hy(nHoles), hLife(nHoles)
  99.     FOR i = 1 TO nHoles
  100.         GOSUB newHole
  101.     NEXT
  102.  
  103.     tfStart = 0
  104.     FOR layr = 1 TO 30
  105.         LINE (0, 0)-(wW, wH), _RGBA32(255, 255, 0, 50), BF 'layer of cheese
  106.         FOR i = 1 TO nHoles 'holes in layer
  107.             IF hLife(i) + 1 > maxHoleLife THEN GOSUB newHole ELSE hLife(i) = hLife(i) + 1
  108.             hx(i) = hx(i) + RND * 2 - 1
  109.             hy(i) = hy(i) + RND * 2 - 1
  110.             IF hLife(i) < maxHoleRadius THEN
  111.                 radius = hLife(i)
  112.             ELSEIF maxHoleLife - hLife(i) < maxHoleRadius THEN
  113.                 radius = maxHoleLife - hLife(i)
  114.             ELSE
  115.                 radius = maxHoleRadius
  116.             END IF
  117.             COLOR _RGBA32(0, 0, 0, 50)
  118.             fcirc hx(i), hy(i), radius
  119.         NEXT
  120.     NEXT
  121.  
  122.  
  123.     _DEST curr&
  124.     EXIT SUB
  125.  
  126.     newHole:
  127.     hx(i) = wW * RND
  128.     hy(i) = wH * RND
  129.     IF tfStart THEN hLife(i) = INT(RND * maxHoleLife) ELSE hLife(i) = 1
  130.     RETURN
  131.  
  133.  
  134. 'Steve McNeil's  copied from his forum   note: Radius is too common a name
  135. SUB fcirc (CX AS LONG, CY AS LONG, R AS LONG)
  136.     DIM subRadius AS LONG, RadiusError AS LONG
  137.     DIM X AS LONG, Y AS LONG
  138.  
  139.     subRadius = ABS(R)
  140.     RadiusError = -subRadius
  141.     X = subRadius
  142.     Y = 0
  143.  
  144.     IF subRadius = 0 THEN PSET (CX, CY): EXIT SUB
  145.  
  146.     ' Draw the middle span here so we don't draw it twice in the main loop,
  147.     ' which would be a problem with blending turned on.
  148.     LINE (CX - X, CY)-(CX + X, CY), , BF
  149.  
  150.     WHILE X > Y
  151.         RadiusError = RadiusError + Y * 2 + 1
  152.         IF RadiusError >= 0 THEN
  153.             IF X <> Y + 1 THEN
  154.                 LINE (CX - Y, CY - X)-(CX + Y, CY - X), , BF
  155.                 LINE (CX - Y, CY + X)-(CX + Y, CY + X), , BF
  156.             END IF
  157.             X = X - 1
  158.             RadiusError = RadiusError - X * 2
  159.         END IF
  160.         Y = Y + 1
  161.         LINE (CX - X, CY - Y)-(CX + X, CY - Y), , BF
  162.         LINE (CX - X, CY + Y)-(CX + X, CY + Y), , BF
  163.     WEND
  165.  
Title: Re: _MAPTRIANGLE Distortion
Post by: Petr on August 02, 2018, 05:02:49 pm
Hi Bplus. I test it, you map not the same areas. If i understand it correctly, then muss be values for cx, cy the same as for x, y and  cx1, cy1 the same as for x1, y1  and cx2, cy2 the same as for x2, y2 in begin - angle 0, but are not the same.
Title: Re: _MAPTRIANGLE Distortion
Post by: bplus on August 02, 2018, 05:20:33 pm
Hi Petr,

Right my x1, cx1 and x2, cx2 are off by 100! Now to track down why?
Title: Re: _MAPTRIANGLE Distortion (Fixed)
Post by: bplus on August 02, 2018, 05:59:36 pm
Fixed, I was using the wrong number for the center of the cheese from which I was mapping.

Thanks Petr, for getting me started on checking actual numbers.

So it was my blunder, a shocker! ;D

Code: QB64: [Select]
  1. _TITLE "Cheese Factory 2"
  2. 'QB64 X 64 version 1.2 20180228/86  from git b301f92
  3.  
  4. '2018-08-01 started from idea I had while trying to fix holes in Colbalt's cheese wedge shooter
  5. '2018-08-02 Make growCheese sub completely self contained
  6. ' fix shooter:
  7. '1. shooterX, shooterY must be in center of wedge
  8. '2. wedge needs rounded back as if cut from round cheese cake
  9.  
  10. CONST wW = 800
  11. CONST wH = 600
  12. CONST sR = 100
  13.  
  14. SCREEN _NEWIMAGE(wW, wH, 32)
  15. _SCREENMOVE 360, 60
  17. DIM SHARED shooterX, shooterY, shooterA
  18. shooterX = 400: shooterY = 300
  19.  
  20. DIM SHARED cheese&
  21.  
  22.  
  23. restart:
  24. growCheese
  25. _PUTIMAGE , cheese&
  26. shooterA = 0
  27. 'OK on the cheese here is outline of where the shooter wedge will be mapped
  28. COLOR _RGB32(0, 0, 0)
  29. CIRCLE (wW / 2, wH / 2), sR + 1
  30. x = shooterX + sR * COS(shooterA)
  31. y = shooterY + sR * SIN(shooterA)
  32. x1 = shooterX + sR * COS(shooterA + _PI(5 / 6))
  33. y1 = shooterY + sR * SIN(shooterA + _PI(5 / 6))
  34. x2 = shooterX + sR * COS(shooterA + _PI(7 / 6))
  35. y2 = shooterY + sR * SIN(shooterA + _PI(7 / 6))
  36. LINE (x, y)-(x1, y1)
  37. LINE (x1, y1)-(x2, y2)
  38. LINE (x2, y2)-(x, y)
  39.  
  40. COLOR _RGB32(255, 255, 0)
  41. _PRINTSTRING (20, 20), "  Here is a sample of the cheese from which we are taking a wedge,  "
  42. _PRINTSTRING (20, 60), "  press any key (except spacebar) to transfer cheese image to shooter surrounded by black square.  "
  43. _PRINTSTRING (20, 100), "  press spacebar for another cheesey layout and wedge cut..  "
  44. _PRINTSTRING (20, 140), "  press left and right arrows to swing shooter around... escape quits.  "
  47.  
  48.  
  49. 'show different patterns of holes
  51.     IF _KEYDOWN(32) THEN GOTO restart
  52.     IF _KEYDOWN(19200) THEN _DELAY .05: shooterA = shooterA - _PI(5 / 360)
  53.     IF _KEYDOWN(19712) THEN _DELAY .05: shooterA = shooterA + _PI(5 / 360)
  54.     LINE (wW / 2 - sR - 5, wH / 2 - sR - 5)-STEP(2 * sR + 10, 2 * sR + 10), _RGB32(0, 0, 0), BF
  55.     drawShooter
  56.     _DISPLAY
  58.  
  59. SUB drawShooter ()
  60.     'first makeCheese and use cheese& image to build shooter image
  61.     'dim shared ShooterX, ShooterY, ShooterA, cheese&
  62.  
  63.     cx0 = wW / 2: cy0 = wH / 2 'fix center for cheese wedge
  64.  
  65.     x = shooterX + sR * COS(shooterA)
  66.     y = shooterY + sR * SIN(shooterA)
  67.     x1 = shooterX + sR * COS(shooterA + _PI(5 / 6))
  68.     y1 = shooterY + sR * SIN(shooterA + _PI(5 / 6))
  69.     cx = cx0 + sR * COS(0)
  70.     cy = cy0 + sR * SIN(0)
  71.     cx1 = cx0 + sR * COS(_PI(5 / 6))
  72.     cy1 = cy0 + sR * SIN(_PI(5 / 6))
  73.  
  74.     'take small traingles off cheese& image  and map them onto main screen at shooter position
  75.     stepper = _PI(1 / 72)
  76.     starter = _PI(5 / 6) + stepper
  77.     stopper = _PI(7 / 6)
  78.     FOR a = starter TO stopper STEP stepper
  79.         'one to one ratio of mapping
  80.         x2 = shooterX + sR * COS(shooterA + a)
  81.         y2 = shooterY + sR * SIN(shooterA + a)
  82.         cx2 = cx0 + sR * COS(a)
  83.         cy2 = cy0 + sR * SIN(a)
  84.         _MAPTRIANGLE (cx, cy)-(cx1, cy1)-(cx2, cy2), cheese& TO(x, y)-(x1, y1)-(x2, y2)
  85.  
  86.         'OK check value matches
  87.         IF a = starter THEN
  88.             LOCATE 30, 1: PRINT shooterX, shooterY, COS(shooterA), SIN(shooterA)
  89.             LOCATE 31, 1: PRINT x, y, cx, cy
  90.             LOCATE 32, 1: PRINT x1, y1, cx1, cy1
  91.             LOCATE 33, 1: PRINT x2, y2, cx2, cy2
  92.         END IF
  93.  
  94.         x1 = x2: y1 = y2: cx1 = cx2: cy1 = cy2
  95.     NEXT
  96.  
  97.     'check overlap:  not perfect but good enough!
  98.     x = shooterX + sR * COS(shooterA)
  99.     y = shooterY + sR * SIN(shooterA)
  100.     x1 = shooterX + sR * COS(shooterA + _PI(5 / 6))
  101.     y1 = shooterY + sR * SIN(shooterA + _PI(5 / 6))
  102.     x2 = shooterX + sR * COS(shooterA + _PI(7 / 6))
  103.     y2 = shooterY + sR * SIN(shooterA + _PI(7 / 6))
  104.     LINE (x, y)-(x1, y1), _RGB32(255, 255, 255)
  105.     LINE (x1, y1)-(x2, y2), _RGB32(255, 255, 255)
  106.     LINE (x2, y2)-(x, y), _RGB32(255, 255, 255)
  107.  
  109.  
  110.  
  111. SUB growCheese () 'make this more self contained than first version, all hole stuff just in here
  112.     curr& = _DEST
  113.     IF cheese& THEN _FREEIMAGE cheese&
  114.     cheese& = _NEWIMAGE(wW, wH, 32)
  115.     _DEST cheese&
  116.     nHoles = 300: maxHoleLife = 20: maxHoleRadius = 7: tfStart = 1
  117.     DIM hx(nHoles), hy(nHoles), hLife(nHoles)
  118.     FOR i = 1 TO nHoles
  119.         GOSUB newHole
  120.     NEXT
  121.  
  122.     tfStart = 0
  123.     FOR layr = 1 TO 30
  124.         LINE (0, 0)-(wW, wH), _RGBA32(255, 255, 0, 50), BF 'layer of cheese
  125.         FOR i = 1 TO nHoles 'holes in layer
  126.             IF hLife(i) + 1 > maxHoleLife THEN GOSUB newHole ELSE hLife(i) = hLife(i) + 1
  127.             hx(i) = hx(i) + RND * 2 - 1
  128.             hy(i) = hy(i) + RND * 2 - 1
  129.             IF hLife(i) < maxHoleRadius THEN
  130.                 radius = hLife(i)
  131.             ELSEIF maxHoleLife - hLife(i) < maxHoleRadius THEN
  132.                 radius = maxHoleLife - hLife(i)
  133.             ELSE
  134.                 radius = maxHoleRadius
  135.             END IF
  136.             COLOR _RGBA32(0, 0, 0, 50)
  137.             fcirc hx(i), hy(i), radius
  138.         NEXT
  139.     NEXT
  140.  
  141.  
  142.     _DEST curr&
  143.     EXIT SUB
  144.  
  145.     newHole:
  146.     hx(i) = wW * RND
  147.     hy(i) = wH * RND
  148.     IF tfStart THEN hLife(i) = INT(RND * maxHoleLife) ELSE hLife(i) = 1
  149.     RETURN
  150.  
  152.  
  153. 'Steve McNeil's  copied from his forum   note: Radius is too common a name
  154. SUB fcirc (CX AS LONG, CY AS LONG, R AS LONG)
  155.     DIM subRadius AS LONG, RadiusError AS LONG
  156.     DIM X AS LONG, Y AS LONG
  157.  
  158.     subRadius = ABS(R)
  159.     RadiusError = -subRadius
  160.     X = subRadius
  161.     Y = 0
  162.  
  163.     IF subRadius = 0 THEN PSET (CX, CY): EXIT SUB
  164.  
  165.     ' Draw the middle span here so we don't draw it twice in the main loop,
  166.     ' which would be a problem with blending turned on.
  167.     LINE (CX - X, CY)-(CX + X, CY), , BF
  168.  
  169.     WHILE X > Y
  170.         RadiusError = RadiusError + Y * 2 + 1
  171.         IF RadiusError >= 0 THEN
  172.             IF X <> Y + 1 THEN
  173.                 LINE (CX - Y, CY - X)-(CX + Y, CY - X), , BF
  174.                 LINE (CX - Y, CY + X)-(CX + Y, CY + X), , BF
  175.             END IF
  176.             X = X - 1
  177.             RadiusError = RadiusError - X * 2
  178.         END IF
  179.         Y = Y + 1
  180.         LINE (CX - X, CY - Y)-(CX + X, CY - Y), , BF
  181.         LINE (CX - X, CY + Y)-(CX + X, CY + Y), , BF
  182.     WEND
  184.  
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