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comparison semiconginev2/old/algorithms.nim @ 1218:56781cc0fc7c compiletime-tests

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did: renamge main package
author sam <sam@basx.dev>
date Wed, 17 Jul 2024 21:01:37 +0700
parents semicongine/old/algorithms.nim@a3eb305bcac2
children
comparison
equal deleted inserted replaced
1217:f819a874058f 1218:56781cc0fc7c
1 import std/algorithm
2
3 import ./core
4
5 type
6 Rect = tuple
7 i: int
8 x, y, w, h: uint32
9
10 func between(a1, a2, b: uint32): bool =
11 a1 <= b and b <= a2
12
13 func overlap(a1, a2, b1, b2: uint32): bool =
14 return between(a1, a2, b1) or
15 between(a1, a2, b2) or
16 between(b1, b2, a1) or
17 between(b1, b2, a2)
18
19 # FYI: also serves as "overlaps"
20 func advanceIfOverlap(fix, newRect: Rect): (bool, uint32) =
21 let overlapping = overlap(fix.x, fix.x + fix.w - 1, newRect.x, newRect.x + newRect.w - 1) and
22 overlap(fix.y, fix.y + fix.h - 1, newRect.y, newRect.y + newRect.h - 1)
23 if overlapping: (true, fix.x + fix.w) # next free x coordinate to the right
24 else: (false, newRect.x) # current position is fine
25
26 proc find_insertion_position(alreadyPlaced: seq[Rect], area: tuple[i: int, w, h: uint32], maxDim: uint32): (bool, Rect) =
27 var newRect = (i: area.i, x: 0'u32, y: 0'u32, w: area.w, h: area.h)
28
29 while newRect.y + newRect.h <= maxDim:
30 var hasOverlap = false
31 var advanceX: uint32
32
33 for placed in alreadyPlaced:
34 (hasOverlap, advanceX) = placed.advanceIfOverlap(newRect)
35 if hasOverlap: # rects were overlapping and newRect needs to be shifted to the right
36 newRect.x = advanceX
37 break
38
39 if not hasOverlap: # found a collision free position
40 return (true, newRect)
41
42 if newRect.x + newRect.w >= maxDim: # move to next scanline
43 newRect.x = 0
44 newRect.y += 1
45
46 return (false, newRect)
47
48
49 proc Pack*[T: Pixel](images: seq[Image[T]]): tuple[atlas: Image[T], coords: seq[tuple[x: uint32, y: uint32]]] =
50 const MAX_ATLAS_SIZE = 4096'u32
51 var areas: seq[tuple[i: int, w, h: uint32]]
52
53 for i in 0 ..< images.len:
54 areas.add (i, images[i].width, images[i].height)
55
56 let areasBySize = areas.sortedByIt(-(it[1] * it[2]).int64)
57 var assignedAreas: seq[Rect]
58 var maxDim = 128'u32
59
60 for area in areasBySize:
61 var pos = find_insertion_position(assignedAreas, area, maxDim)
62 while not pos[0]: # this should actually never loop more than once, but weird things happen ¯\_(ツ)_/¯
63 maxDim = maxDim * 2
64 assert maxDim <= MAX_ATLAS_SIZE, &"Atlas gets bigger than {MAX_ATLAS_SIZE}, cannot pack images"
65 pos = find_insertion_position(assignedAreas, area, maxDim)
66
67 assignedAreas.add pos[1]
68
69 # check there are overlaps
70 for i in 0 ..< assignedAreas.len - 1:
71 for j in i + 1 ..< assignedAreas.len:
72 assert not assignedAreas[i].advanceIfOverlap(assignedAreas[j])[0], &"{assignedAreas[i]} and {assignedAreas[j]} overlap!"
73
74 result.atlas = NewImage[T](maxDim, maxDim)
75 result.coords.setLen(images.len)
76 for rect in assignedAreas:
77 for y in 0 ..< rect.h:
78 for x in 0 ..< rect.w:
79 assert result.atlas[rect.x + x, rect.y + y] == 0, "Atlas texture packing encountered an overlap error"
80 result.atlas[rect.x + x, rect.y + y] = images[rect.i][x, y]
81 result.coords[rect.i] = (x: rect.x, y: rect.y)