mirror of
https://github.com/EsotericSoftware/spine-runtimes.git
synced 2025-12-20 17:26:01 +08:00
337 lines
9.9 KiB
Lua
337 lines
9.9 KiB
Lua
-------------------------------------------------------------------------------
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-- Spine Runtimes Software License v2.5
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--
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-- Copyright (c) 2013-2016, Esoteric Software
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-- All rights reserved.
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--
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-- You are granted a perpetual, non-exclusive, non-sublicensable, and
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-- non-transferable license to use, install, execute, and perform the Spine
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-- Runtimes software and derivative works solely for personal or internal
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-- use. Without the written permission of Esoteric Software (see Section 2 of
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-- the Spine Software License Agreement), you may not (a) modify, translate,
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-- adapt, or develop new applications using the Spine Runtimes or otherwise
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-- create derivative works or improvements of the Spine Runtimes or (b) remove,
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-- delete, alter, or obscure any trademarks or any copyright, trademark, patent,
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-- or other intellectual property or proprietary rights notices on or in the
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-- Software, including any copy thereof. Redistributions in binary or source
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-- form must include this license and terms.
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--
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-- THIS SOFTWARE IS PROVIDED BY ESOTERIC SOFTWARE "AS IS" AND ANY EXPRESS OR
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-- IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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-- MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
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-- EVENT SHALL ESOTERIC SOFTWARE BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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-- SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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-- PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, BUSINESS INTERRUPTION, OR LOSS OF
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-- USE, DATA, OR PROFITS) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
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-- IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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-- ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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-- POSSIBILITY OF SUCH DAMAGE.
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-------------------------------------------------------------------------------
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local utils = require "spine-lua.utils"
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local setmetatable = setmetatable
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local math_min = math.min
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local math_max = math.max
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local ipairs = ipairs
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local table_insert = table.insert
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local table_remove = table.remove
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local Triangulator = {}
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Triangulator.__index = Triangulator
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function Triangulator.new ()
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local self = {
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convexPolygons = {},
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convexPolygonsIndices = {},
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indicesArray = {},
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isConcaveArray = {},
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triangles = {}
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}
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setmetatable(self, Triangulator)
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return self
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end
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function Triangulator:triangulate (verticesArray)
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local vertices = verticesArray
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local vertexCount = #verticesArray / 2
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self.indicesArray = {}
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local indicesArray = self.indicesArray
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local indices = utils.setArraySize(indicesArray, vertexCount)
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local i = 0
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while i < vertexCount do
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indices[i] = i
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i = i + 1
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end
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local isConcaveArray = self.isConcaveArray
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local isConcave = isConcaveArray
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i = 0
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while i < vertexCount do
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isConcave[i] = self:isConcave(i, vertexCount, vertices, indices)
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i = i + 1
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end
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self.triangles = {}
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local triangles = self.triangles;
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while vertexCount > 3 do
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-- Find ear tip.
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local previous = vertexCount - 1
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local i = 0
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local _next = 1
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while true do
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local goToHead = false
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local breakLoop = false
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if not isConcave[i] then
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local p1 = indices[previous] * 2 + 1
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local p2 = indices[i] * 2 + 1
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local p3 = indices[_next] * 2 + 1
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local p1x = vertices[p1]
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local p1y = vertices[p1 + 1]
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local p2x = vertices[p2]
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local p2y = vertices[p2 + 1]
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local p3x = vertices[p3]
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local p3y = vertices[p3 + 1]
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local ii = ((_next + 1) % vertexCount)
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while ii ~= previous do
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if isConcave[ii] then
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local v = indices[ii] * 2 + 1
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local vx = vertices[v]
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local vy = vertices[v + 1]
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if self:positiveArea(p3x, p3y, p1x, p1y, vx, vy) then
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if self:positiveArea(p1x, p1y, p2x, p2y, vx, vy) then
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if self:positiveArea(p2x, p2y, p3x, p3y, vx, vy) then
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goToHead = true
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break
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end
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end
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end
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end
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ii = (ii + 1) % vertexCount
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end
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if (not goToHead) then
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breakLoop = true
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break
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end
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end
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if breakLoop then break end
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if _next == 0 then
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repeat
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if not isConcave[i] then
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break;
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end
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i = i - 1
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until i == 0
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break
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end
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previous = i
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i = _next
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_next = (_next + 1) % vertexCount
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end
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-- Cut ear tip.
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table_insert(triangles, indices[(vertexCount + i - 1) % vertexCount] + 1)
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table_insert(triangles, indices[i] + 1)
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table_insert(triangles, indices[(i + 1) % vertexCount] + 1)
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if i == 0 then
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local ii = 1
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while ii <= #indicesArray do
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indicesArray[ii-1] = indicesArray[ii]
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isConcaveArray[ii-1] = isConcaveArray[ii]
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ii = ii + 1
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end
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else
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table_remove(indicesArray, i)
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table_remove(isConcaveArray, i)
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end
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vertexCount = vertexCount - 1
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local previousIndex = (vertexCount + i - 1) % vertexCount
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local nextIndex = i
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if i == vertexCount then nextIndex = 0 end
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isConcave[previousIndex] = self:isConcave(previousIndex, vertexCount, vertices, indices)
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isConcave[nextIndex] = self:isConcave(nextIndex, vertexCount, vertices, indices)
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end
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if vertexCount == 3 then
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table_insert(triangles, indices[2] + 1)
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table_insert(triangles, indices[0] + 1)
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table_insert(triangles, indices[1] + 1)
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end
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return triangles
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end
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function Triangulator:decompose(verticesArray, triangles)
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local vertices = verticesArray
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self.convexPolygons = {}
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local convexPolygons = self.convexPolygons;
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self.convexPolygonsIndices = {}
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local convexPolygonsIndices = self.convexPolygonsIndices;
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local polygonIndices = {}
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local polygon = {}
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-- Merge subsequent triangles if they form a triangle fan.
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local fanBaseIndex = -1
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local lastWinding = 0
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local trianglesItems = triangles
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local i = 1
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local n = #triangles
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while i <= n do
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local t1 = (trianglesItems[i] - 1) * 2 + 1
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local t2 = (trianglesItems[i + 1] - 1) * 2 + 1
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local t3 = (trianglesItems[i + 2] - 1) * 2 + 1
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local x1 = vertices[t1]
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local y1 = vertices[t1 + 1]
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local x2 = vertices[t2]
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local y2 = vertices[t2 + 1]
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local x3 = vertices[t3]
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local y3 = vertices[t3 + 1]
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-- If the base of the last triangle is the same as this triangle, check if they form a convex polygon (triangle fan).
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local merged = false;
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if fanBaseIndex == t1 then
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local o = #polygon - 4 + 1;
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local p = polygon;
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local winding1 = self:winding(p[o], p[o + 1], p[o + 2], p[o + 3], x3, y3);
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local winding2 = self:winding(x3, y3, p[1], p[2], p[3], p[4]);
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if winding1 == lastWinding and winding2 == lastWinding then
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table_insert(polygon, x3)
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table_insert(polygon, y3)
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table_insert(polygonIndices, t3)
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merged = true
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end
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end
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-- Otherwise make this triangle the new base.
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if not merged then
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if #polygon > 0 then
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table_insert(convexPolygons, polygon)
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table_insert(convexPolygonsIndices, polygonIndices)
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end
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polygon = {}
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table_insert(polygon, x1)
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table_insert(polygon, y1)
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table_insert(polygon, x2)
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table_insert(polygon, y2)
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table_insert(polygon, x3)
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table_insert(polygon, y3)
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polygonIndices = {}
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table_insert(polygonIndices, t1)
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table_insert(polygonIndices, t2);
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table_insert(polygonIndices, t3);
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lastWinding = self:winding(x1, y1, x2, y2, x3, y3)
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fanBaseIndex = t1
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end
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i = i + 3
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end
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if #polygon > 0 then
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table_insert(convexPolygons, polygon)
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table_insert(convexPolygonsIndices, polygonIndices)
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end
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-- Go through the list of polygons and try to merge the remaining triangles with the found triangle fans.
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i = 1
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n = #convexPolygons
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while i <= n do
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polygonIndices = convexPolygonsIndices[i]
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if (#polygonIndices > 0) then
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local firstIndex = polygonIndices[1]
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local lastIndex = polygonIndices[#polygonIndices]
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polygon = convexPolygons[i]
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local o = #polygon - 4 + 1
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local p = polygon
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local prevPrevX = p[o]
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local prevPrevY = p[o + 1]
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local prevX = p[o + 2]
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local prevY = p[o + 3]
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local firstX = p[1]
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local firstY = p[2]
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local secondX = p[3]
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local secondY = p[4]
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local winding = self:winding(prevPrevX, prevPrevY, prevX, prevY, firstX, firstY)
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local ii = 1
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while ii <= n do
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if ii ~= i then
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local otherIndices = convexPolygonsIndices[ii]
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if (#otherIndices == 3) then
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local otherFirstIndex = otherIndices[1];
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local otherSecondIndex = otherIndices[2];
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local otherLastIndex = otherIndices[3];
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local otherPoly = convexPolygons[ii];
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local x3 = otherPoly[#otherPoly - 2 + 1]
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local y3 = otherPoly[#otherPoly - 1 + 1]
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if not (otherFirstIndex ~= firstIndex or otherSecondIndex ~= lastIndex) then
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local winding1 = self:winding(prevPrevX, prevPrevY, prevX, prevY, x3, y3)
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local winding2 = self:winding(x3, y3, firstX, firstY, secondX, secondY)
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if winding1 == winding and winding2 == winding then
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convexPolygons[ii] = {}
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convexPolygonsIndices[ii] = {}
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table_insert(polygon, x3)
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table_insert(polygon, y3)
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table_insert(polygonIndices, otherLastIndex)
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prevPrevX = prevX
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prevPrevY = prevY
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prevX = x3
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prevY = y3
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ii = 1
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end
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end
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end
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end
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ii = ii + 1
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end
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end
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i = i + 1
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end
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-- Remove empty polygons that resulted from the merge step above.
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i = #convexPolygons
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while i >= 1 do
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polygon = convexPolygons[i]
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if #polygon == 0 then
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table_remove(convexPolygons, i)
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end
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i = i - 1
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end
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return convexPolygons;
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end
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function Triangulator:isConcave(index, vertexCount, vertices, indices)
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local previous = indices[(vertexCount + index - 1) % vertexCount] * 2 + 1;
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local current = indices[index] * 2 + 1;
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local _next = indices[(index + 1) % vertexCount] * 2 + 1;
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return not self:positiveArea(vertices[previous], vertices[previous + 1], vertices[current], vertices[current + 1], vertices[_next],vertices[_next + 1]);
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end
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function Triangulator:positiveArea(p1x, p1y, p2x, p2y, p3x, p3y)
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return p1x * (p3y - p2y) + p2x * (p1y - p3y) + p3x * (p2y - p1y) >= 0
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end
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function Triangulator:winding(p1x, p1y, p2x, p2y, p3x, p3y)
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local px = p2x - p1x
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local py = p2y - p1y
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if p3x * py - p3y * px + px * p1y - p1x * py >= 0 then
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return 1
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else
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return -1;
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end
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end
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return Triangulator
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