pixie/experiments/trapezoid.nim
2021-11-27 19:06:22 -08:00

308 lines
7.9 KiB
Nim

import algorithm, bumpy, chroma, pixie/images, print,
sequtils, vmath, benchy
import pixie, pixie/paths {.all.}
printColors = false
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:
at = a.at + (t * s1)
return true
type Trapezoid = object
nw, ne, se, sw: Vec2
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 fillPath2(mask: Mask, p: Path) =
var polygons = p.commandsToShapes()
const q = 1/256.0
# Creates segment q, quantize and remove verticals.
var segments1: seq[Segment]
for shape in polygons:
for s in shape.segments:
var s = s
s.at = s.at.roundBy(q)
s.to = s.to.roundBy(q)
if s.at.y != s.to.y:
if s.at.y > s.to.y:
# make sure segments always are at.y higher
swap(s.at, s.to)
segments1.add(s)
# There is probably a clever way to insert-sort them.
var yScanLines: seq[float32]
for s in segments1:
if s.at.y notin yScanLines:
yScanLines.add s.at.y
if s.to.y notin yScanLines:
yScanLines.add s.to.y
yScanLines.sort()
print yScanLines
var segments: seq[Segment]
while segments1.len > 0:
#print segments1.len, segments.len
var s = segments1.pop()
var collision = false
for y in yScanLines:
let scanLine = line(vec2(0, y), vec2(1, y))
var at: Vec2
if intersects(scanLine, s, at):
at = at.roundBy(q)
at.y = y
if s.at.y != at.y and s.to.y != at.y:
#print "seg2yline intersects!", a, y, at
collision = true
var s1 = segment(s.at, at)
var s2 = segment(at, s.to)
#print s.length, "->", s1.length, s2.length
segments1.add(s1)
segments1.add(s2)
break
if not collision:
# means its touching, not intersecting
segments.add(s)
# sort at/to in segments
# for s in segments.mitems:
# if s.at.y > s.to.y:
# swap(s.at, s.to)
#let blender = blendMode.blender()
for yScanLine in yScanLines[0..^2]:
var scanSegments: seq[Segment]
for s in segments:
if s.at.y == yScanLine:
scanSegments.add(s)
scanSegments.sort(proc(a, b: Segment): int =
cmp(a.at.x, b.at.x))
# if scanSegments.len mod 2 != 0:
# print "error???"
# print yScanLine
# print scanSegments
# quit()
# TODO: winding rules will go here
var trapezoids: seq[Trapezoid]
for i in 0 ..< scanSegments.len div 2:
let
a = scanSegments[i*2+0]
b = scanSegments[i*2+1]
assert a.at.y == b.at.y
assert a.to.y == b.to.y
#assert a.at.x < b.at.x
#assert a.to.x < b.to.x
trapezoids.add(Trapezoid(
nw: a.at,
ne: b.at,
se: b.to, # + vec2(0,0.7),
sw: a.to # + vec2(0,0.7)
))
var i = 0
while i < trapezoids.len:
let t = trapezoids[i]
# print t
let
nw = t.nw
ne = t.ne
se = t.se
sw = t.sw
let
height = sw.y - nw.y
minYf = nw.y
maxYf = sw.y
minYi = minYf.floor.int
maxYi = maxYf.floor.int
# print t
for y in minYi .. maxYi:
let
yFrac = (y.float - nw.y) / height
minXf = mix(nw.x, sw.x, yFrac)
maxXf = mix(ne.x, se.x, yFrac)
minXi = minXf.floor.int
maxXi = maxXf.floor.int
#print yFrac
# if not(minY.int == 58 or maxY.int == 58) or minX > 100:
# continue
var ay: float32
if y == minYi and y == maxYi:
ay = maxYf - minYf
# print "middle", maxYf, minYf, a
#print "double", y, a, minY, maxY, round(a * 255)
elif y == minYi:
ay = (1 - (minYf - float32(minYi)))
# print "min y", minYf, minYi, a
#print "s", y, a, minY, round(a * 255)
elif y == maxYi:
ay = (maxYf - float32(maxYi))
#print "max y", maxYf, maxYi, a
# print "e", y, a, maxY, round(a * 255)
else:
ay = 1.0
for x in minXi .. maxXi:
var ax: float32
# if x == minXi:
# a2 = (1 - (minXf - float32(minXi)))
# #a2 = 1.0
# elif x == maxXi:
# a2 = (maxXf - float32(maxXi))
# #a2 = 1.0
# else:
# a2 = 1.0
if x.float32 < max(nw.x, sw.x):
ax = 0.5
elif x.float32 > min(ne.x, se.x):
ax = 0.25
else:
ax = 1.0
let backdrop = mask.getValueUnsafe(x, y)
mask.setValueUnsafe(x, y, backdrop + floor(255 * ay * ax).uint8)
# if x == 100 and y == 172:
# print backdrop, round(255 * a * a2).uint8
# print mask.getValueUnsafe(x, y)
inc i
block:
# Rect
print "rect"
#var image = newImage(200, 200)
# var p = Path()
# p.moveTo(50.25, 50.25)
# p.lineTo(50.25, 150.25)
# p.lineTo(150.25, 150.25)
# p.lineTo(150.25, 50.25)
# p.closePath()
var p = 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
""")
# image.fill(rgba(255, 255, 255, 255))
#image.fillPath2(p, color(0, 0, 0, 1))
var mask = newMask(200, 200)
timeIt "rect trapezoids", 1:
#for i in 0 ..< 100:
mask.fill(0)
mask.fillPath2(p)
#image.fillPath2(p, color(0, 0, 0, 1))
mask.writeFile("experiments/trapezoids/rect_trapesoid.png")
var mask2 = newMask(200, 200)
timeIt "rect normal", 1:
#for i in 0 ..< 100:
mask2.fill(0)
mask2.fillPath(p)
mask2.writeFile("experiments/trapezoids/rect_scanline.png")
let (score, image) = diff(mask.newImage, mask2.newImage)
print score
image.writeFile("experiments/trapezoids/rect_diff.png")
# block:
# # Rhombus
# print "rhombus"
# var image = newImage(200, 200)
# image.fill(rgba(255, 255, 255, 255))
# var p = Path()
# p.moveTo(100, 50)
# p.lineTo(150, 100)
# p.lineTo(100, 150)
# p.lineTo(50, 100)
# p.closePath()
# image.fillPath2(p, color(0, 0, 0, 1))
# image.writeFile("experiments/trapezoids/rhombus.png")
# block:
# # heart
# print "heart"
# var image = newImage(400, 400)
# image.fill(rgba(0, 0, 0, 0))
# var p = parsePath("""
# M 40 120 A 80 80 90 0 1 200 120 A 80 80 90 0 1 360 120
# Q 360 240 200 360 Q 40 240 40 120 z
# """)
# var mask = newMask(image)
# mask.fillPath2(p)
# image.draw(mask, blendMode = bmOverwrite)
# image.writeFile("experiments/trapezoids/heart.png")
# block:
# # l
# print "l"
# var image = newImage(500, 800)
# image.fill(rgba(255, 255, 255, 255))
# var p = parsePath("""
# M 236 20 Q 150 22 114 57 T 78 166 V 790 L 171 806 V 181 Q 171 158 175 143 T 188 119 T 212 105.5 T 249 98 Z
# """)
# image.fillPath2(p, color(0, 0, 0, 1))
# image.writeFile("experiments/trapezoids/l.png")
# block:
# # g
# print "g"
# var image = newImage(500, 800)
# image.fill(rgba(255, 255, 255, 255))
# var p = 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
# """)
# image.fillPath2(p, color(0, 0, 0, 1))
# image.writeFile("experiments/trapezoids/g.png")