pixie/experiments/sweeps2.nim
2021-11-28 16:03:26 -08:00

482 lines
13 KiB
Nim

import algorithm, bumpy, chroma, pixie/images, print,
vmath, benchy, fidget2/perf
import pixie, pixie/paths {.all.}
when defined(release):
{.push checks: off.}
proc pixelCover(a0, b0: Vec2): float32 =
## Returns the amount of area a given segment sweeps to the right
## in a [0,0 to 1,1] box.
var
a = a0
b = b0
aI: Vec2
bI: Vec2
area: float32 = 0.0
# # Sort A on top.
# if a.y > b.y:
# let tmp = a
# a = b
# b = tmp
# if (b.y < 0 or a.y > 1) or # Above or bellow, no effect.
# (a.x >= 1 and b.x >= 1) or # To the right, no effect.
# (a.y == b.y): # Horizontal line, no effect.
# return 0
if (a.x < 0 and b.x < 0) or # Both to the left.
(a.x == b.x): # Vertical line
# Area of the rectangle:
return (1 - clamp(a.x, 0, 1)) * (min(b.y, 1) - max(a.y, 0))
else:
# y = mm*x + bb
let
mm: float32 = (b.y - a.y) / (b.x - a.x)
bb: float32 = a.y - mm * a.x
if a.x >= 0 and a.x <= 1 and a.y >= 0 and a.y <= 1:
# A is in pixel bounds.
aI = a
else:
aI = vec2((0 - bb) / mm, 0)
if aI.x < 0:
let y = mm * 0 + bb
# Area of the extra rectangle.
area += (min(bb, 1) - max(a.y, 0)).clamp(0, 1)
aI = vec2(0, y.clamp(0, 1))
elif aI.x > 1:
let y = mm * 1 + bb
aI = vec2(1, y.clamp(0, 1))
if b.x >= 0 and b.x <= 1 and b.y >= 0 and b.y <= 1:
# B is in pixel bounds.
bI = b
else:
bI = vec2((1 - bb) / mm, 1)
if bI.x < 0:
let y = mm * 0 + bb
# Area of the extra rectangle.
area += (min(b.y, 1) - max(bb, 0)).clamp(0, 1)
bI = vec2(0, y.clamp(0, 1))
elif bI.x > 1:
let y = mm * 1 + bb
bI = vec2(1, y.clamp(0, 1))
area += ((1 - aI.x) + (1 - bI.x)) / 2 * (bI.y - aI.y)
return area
proc intersectsInner*(a, b: Segment, at: var Vec2): bool {.inline.} =
## Checks if the a segment intersects b segment.
## If it returns true, at will have point of intersection
let
s1 = a.to - a.at
s2 = b.to - b.at
denominator = (-s2.x * s1.y + s1.x * s2.y)
s = (-s1.y * (a.at.x - b.at.x) + s1.x * (a.at.y - b.at.y)) / denominator
t = (s2.x * (a.at.y - b.at.y) - s2.y * (a.at.x - b.at.x)) / denominator
if s > 0 and s < 1 and t > 0 and t < 1:
#print s, t
at = a.at + (t * s1)
return true
type
Trapezoid = object
nw, ne, se, sw: Vec2
Line = object
#m, x, b: float32
atx, tox: float32
winding: int16
proc toLine(s: (Segment, int16)): Line =
var line = Line()
# y = mx + b
line.atx = s[0].at.x
line.tox = s[0].to.x
line.winding = s[1]
# line.m = (s.at.y - s.to.y) / (s.at.x - s.to.x)
# line.b = s.at.y - line.m * s.at.x
return line
proc roundBy*(v: Vec2, n: float32): Vec2 {.inline.} =
result.x = sign(v.x) * round(abs(v.x) / n) * n
result.y = sign(v.y) * round(abs(v.y) / n) * n
proc computeBounds(polygons: seq[seq[Vec2]]): Rect =
## Compute the bounds of the segments.
var
xMin = float32.high
xMax = float32.low
yMin = float32.high
yMax = float32.low
for segments in polygons:
for v in segments:
xMin = min(xMin, v.x)
xMax = max(xMax, v.x)
yMin = min(yMin, v.y)
yMax = max(yMax, v.y)
if xMin.isNaN() or xMax.isNaN() or yMin.isNaN() or yMax.isNaN():
discard
else:
result.x = xMin
result.y = yMin
result.w = xMax - xMin
result.h = yMax - yMin
proc binaryInsert(arr: var seq[float32], v: float32) =
if arr.len == 0:
arr.add(v)
return
var
L = 0
R = arr.len - 1
while L < R:
let m = (L + R) div 2
if arr[m] ~= v:
return
elif arr[m] < v:
L = m + 1
else: # arr[m] > v:
R = m - 1
if arr[L] ~= v:
return
elif arr[L] > v:
#print "insert", v, arr, L, R
arr.insert(v, L)
else:
#print "insert", v, arr, L, R
arr.insert(v, L + 1)
proc fillPath2(image: Image, p: Path, color: Color, windingRule = wrNonZero, blendMode = bmNormal) =
const q = 1/256.0
let rgbx = color.rgbx
var segments = p.commandsToShapes(true, 1.0).shapesToSegments()
let
bounds = computeBounds(segments).snapToPixels()
startX = max(0, bounds.x.int)
# Create sorted segments and quantize.
segments.sort(proc(a, b: (Segment, int16)): int = cmp(a[0].at.y, b[0].at.y))
# Compute cut lines
var cutLines: seq[float32]
for s in segments:
cutLines.binaryInsert(s[0].at.y)
cutLines.binaryInsert(s[0].to.y)
var
sweeps = newSeq[seq[Line]](cutLines.len - 1) # dont add bottom cutLine
lastSeg = 0
i = 0
while i < sweeps.len:
#for i, sweep in sweeps.mpairs:
#print "sweep", i, cutLines[i]
if lastSeg < segments.len:
while segments[lastSeg][0].at.y == cutLines[i]:
let s = segments[lastSeg]
if s[0].at.y != s[0].to.y:
#print s
if s[0].to.y != cutLines[i + 1]:
#print "needs cut?", s
#quit("need to cut lines")
var at: Vec2
var seg = s[0]
for j in i ..< sweeps.len:
let y = cutLines[j + 1]
if intersects(line(vec2(0, y), vec2(1, y)), seg, at):
#print "cutting", j, seg
#print "add cut", j, segment(seg.at, at)
sweeps[j].add(toLine((segment(seg.at, at), s[1])))
seg = segment(at, seg.to)
else:
if seg.at.y != seg.to.y:
#print "add rest", j, segment(seg.at, seg.to)
sweeps[j].add(toLine(s))
# else:
# print "micro?"
break
else:
#print "add", s
sweeps[i].add(toLine(s))
inc lastSeg
if lastSeg >= segments.len:
break
inc i
i = 0
while i < sweeps.len:
for t in 0 ..< 10:
# keep cutting sweep
var needsCut = false
var cutterLine: float32 = 0
block doubleFor:
for a in sweeps[i]:
let aSeg = segment(vec2(a.atx, cutLines[i]), vec2(a.tox, cutLines[i+1]))
for b in sweeps[i]:
let bSeg = segment(vec2(b.atx, cutLines[i]), vec2(b.tox, cutLines[i+1]))
var at: Vec2
if intersectsInner(aSeg, bSeg, at):
needsCut = true
cutterLine = at.y
break doubleFor
if needsCut:
var
thisSweep = sweeps[i]
sweeps[i].setLen(0)
sweeps.insert(newSeq[Line](), i + 1)
for a in thisSweep:
let seg = segment(vec2(a.atx, cutLines[i]), vec2(a.tox, cutLines[i+1]))
var at: Vec2
if intersects(line(vec2(0, cutterLine), vec2(1, cutterLine)), seg, at):
sweeps[i+0].add(toLine((segment(seg.at, at), a.winding)))
sweeps[i+1].add(toLine((segment(at, seg.to), a.winding)))
cutLines.binaryInsert(cutterLine)
else:
break
inc i
i = 0
while i < sweeps.len:
# Sort the sweep by X
sweeps[i].sort proc(a, b: Line): int =
result = cmp(a.atx, b.atx)
if result == 0:
result = cmp(a.tox, b.tox)
# Do winding order
var
pen = 0
prevFill = false
j = 0
# print "sweep", i, "--------------"
while j < sweeps[i].len:
let a = sweeps[i][j]
# print a.winding
if a.winding == 1:
inc pen
if a.winding == -1:
dec pen
# print j, pen, prevFill, shouldFill(windingRule, pen)
let thisFill = shouldFill(windingRule, pen)
if prevFill == thisFill:
# remove this line
# print "remove", j
sweeps[i].delete(j)
continue
prevFill = thisFill
inc j
# print sweeps[i]
inc i
#print sweeps
# for s in 0 ..< sweeps.len:
# let
# y1 = cutLines[s]
# echo "M -100 ", y1
# echo "L 300 ", y1
# for line in sweeps[s]:
# let
# nw = vec2(line.atx, cutLines[s])
# sw = vec2(line.tox, cutLines[s + 1])
# echo "M ", nw.x, " ", nw.y
# echo "L ", sw.x, " ", sw.y
proc computeCoverage(
coverages: var seq[uint8],
y: int,
startX: int,
cutLines: seq[float32],
currCutLine: int,
sweep: seq[Line]
) =
# if sweep.len mod 2 != 0:
# return
let
sweepHeight = cutLines[currCutLine + 1] - cutLines[currCutLine]
yFracTop = ((y.float32 - cutLines[currCutLine]) / sweepHeight).clamp(0, 1)
yFracBottom = ((y.float32 + 1 - cutLines[currCutLine]) / sweepHeight).clamp(0, 1)
var i = 0
while i < sweep.len:
let
nwX = mix(sweep[i+0].atx, sweep[i+0].tox, yFracTop)
neX = mix(sweep[i+1].atx, sweep[i+1].tox, yFracTop)
swX = mix(sweep[i+0].atx, sweep[i+0].tox, yFracBottom)
seX = mix(sweep[i+1].atx, sweep[i+1].tox, yFracBottom)
minWi = min(nwX, swX).int
maxWi = max(nwX, swX).ceil.int
minEi = min(neX, seX).int
maxEi = max(neX, seX).ceil.int
let
nw = vec2(sweep[i+0].atx, cutLines[currCutLine])
sw = vec2(sweep[i+0].tox, cutLines[currCutLine + 1])
for x in minWi ..< maxWi:
var area = pixelCover(nw - vec2(x.float32, y.float32), sw - vec2(x.float32, y.float32))
coverages[x - startX] += (area * 255).uint8
let x = maxWi
var midArea = pixelCover(nw - vec2(x.float32, y.float32), sw - vec2(x.float32, y.float32))
var midArea8 = (midArea * 255).uint8
for x in maxWi ..< minEi:
coverages[x - startX] += midArea8
let
ne = vec2(sweep[i+1].atx, cutLines[currCutLine])
se = vec2(sweep[i+1].tox, cutLines[currCutLine + 1])
for x in minEi ..< maxEi:
var area = midArea - pixelCover(ne - vec2(x.float32, y.float32), se - vec2(x.float32, y.float32))
coverages[x - startX] += (area * 255).uint8
i += 2
var
currCutLine = 0
coverages = newSeq[uint8](bounds.w.int)
for scanLine in cutLines[0].int ..< cutLines[^1].ceil.int:
zeroMem(coverages[0].addr, coverages.len)
coverages.computeCoverage(scanLine, startX, cutLines, currCutLine, sweeps[currCutLine])
while cutLines[currCutLine + 1] < scanLine.float + 1.0:
inc currCutLine
if currCutLine == sweeps.len:
break
coverages.computeCoverage(scanLine, startX, cutLines, currCutLine, sweeps[currCutLine])
image.fillCoverage(
rgbx,
startX = startX,
y = scanLine,
coverages,
blendMode
)
when defined(release):
{.pop.}
template test(name: string, p: Path, a: static int = 1, wr = wrNonZero) =
echo name
var image = newImage(200, 200)
timeIt " sweeps", a:
for i in 0 ..< a:
image.fill(color(0, 0, 0, 0))
image.fillPath2(p, color(1, 0, 0, 1), windingRule = wr)
image.writeFile("experiments/trapezoids/output_sweep.png")
var image2 = newImage(200, 200)
timeIt " scanline", a:
for i in 0 ..< a:
image2.fill(color(0, 0, 0, 0))
image2.fillPath(p, color(1, 0, 0, 1), windingRule = wr)
image2.writeFile("experiments/trapezoids/output_scanline.png")
let (score, diff) = diff(image, image2)
if score > 0.05:
echo "does not appear ot match"
diff.writeFile("experiments/trapezoids/output_diff.png")
var rect = Path()
rect.moveTo(50.5, 50.5)
rect.lineTo(50.5, 150.5)
rect.lineTo(150.5, 150.5)
rect.lineTo(150.5, 50.5)
rect.closePath()
var rhombus = Path()
rhombus.moveTo(100, 50)
rhombus.lineTo(150, 100)
rhombus.lineTo(100, 150)
rhombus.lineTo(50, 100)
rhombus.closePath()
var heart = parsePath("""
M 20 60
A 40 40 90 0 1 100 60
A 40 40 90 0 1 180 60
Q 180 120 100 180
Q 20 120 20 60
z
""")
var cricle = Path()
cricle.arc(100, 100, 50, 0, PI * 2, true)
cricle.closePath()
# Half arc (test cut lines)
var halfAarc = parsePath("""
M 25 25 C 85 25 85 125 25 125 z
""")
# Hour glass (test cross lines)
var hourGlass = parsePath("""
M 20 20 L 180 20 L 20 180 L 180 180 z
""")
# Hole
var hole = parsePath("""
M 40 40 L 40 160 L 160 160 L 160 40 z
M 120 80 L 120 120 L 80 120 L 80 80 z
""")
var holeEvenOdd = parsePath("""
M 40 40 L 40 160 L 160 160 L 160 40 z
M 80 80 L 80 120 L 120 120 L 120 80 z
""")
## g
var letterG = parsePath("""
M 406 538 Q 394 546 359.5 558.5 T 279 571 Q 232 571 190.5 556 T 118 509.5 T 69 431 T 51 319 Q 51 262 68 214.5 T 117.5 132.5 T 197 78.5 T 303 59 Q 368 59 416.5 68.5 T 498 86 V 550 Q 498 670 436 724 T 248 778 Q 199 778 155.5 770 T 80 751 L 97 670 Q 125 681 165.5 689.5 T 250 698 Q 333 698 369.5 665 T 406 560 V 538 Z M 405 152 Q 391 148 367.5 144.5 T 304 141 Q 229 141 188.5 190 T 148 320 Q 148 365 159.5 397 T 190.5 450 T 235.5 481 T 288 491 Q 325 491 356 480.5 T 405 456 V 152 Z
""")
letterG.transform(scale(vec2(0.2, 0.2)))
when defined(bench):
test("rect", rect, 100)
test("rhombus", rhombus, 100)
test("heart", heart, 100)
test("cricle", cricle, 100)
test("halfAarc", halfAarc, 100)
test("hourGlass", hourGlass, 100)
test("hole", hole, 100)
test("holeNonZero", holeEvenOdd, 100, wr=wrNonZero)
test("holeEvenOdd", holeEvenOdd, 100, wr=wrEvenOdd)
test("letterG", letterG, 100)
else:
# test("rect", rect)
# test("rhombus", rhombus)
# test("heart", heart)
# test("cricle", cricle)
# test("halfAarc", halfAarc)
# test("hourGlass", hourGlass)
#test("hole", hole, wr=wrEvenOdd)
test("holeNonZero", holeEvenOdd, wr=wrNonZero)
test("holeEvenOdd", holeEvenOdd, wr=wrEvenOdd)
# test("letterG", letterG)