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Use love.math.triangulate instead of own implementation

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This commit is contained in:
Matthias Richter 2014-01-13 22:49:38 +01:00
parent cabee18c81
commit bf35186904
1 changed files with 1 additions and 65 deletions
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66
polygon.lua
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@ -263,71 +263,7 @@ end
-- triangulation by the method of kong -- triangulation by the method of kong
function Polygon:triangulate() function Polygon:triangulate()
if #self.vertices == 3 then return {self:clone()} end return love.math.triangulate(self.vertices)
local triangles = {} -- list of triangles to be returned
local concave = {} -- list of concave edges
local adj = {} -- vertex adjacencies
local vertices = self.vertices
-- retrieve adjacencies as the rest will be easier to implement
for i,p in ipairs(vertices) do
local l = (i == 1) and vertices[#vertices] or vertices[i-1]
local r = (i == #vertices) and vertices[1] or vertices[i+1]
adj[p] = {p = p, l = l, r = r} -- point, left and right neighbor
-- test if vertex is a concave edge
if not ccw(l,p,r) then concave[p] = p end
end
-- and ear is an edge of the polygon that contains no other
-- vertex of the polygon
local function isEar(p1,p2,p3)
if not ccw(p1,p2,p3) then return false end
for q,_ in pairs(concave) do
if q ~= p1 and q ~= p2 and q ~= p3 and pointInTriangle(q, p1,p2,p3) then
return false
end
end
return true
end
-- main loop
local nPoints, skipped = #vertices, 0
local p = adj[ vertices[2] ]
while nPoints > 3 do
if not concave[p.p] and isEar(p.l, p.p, p.r) then
-- polygon may be a 'collinear triangle', i.e.
-- all three points are on a line. In that case
-- the polygon constructor throws an error.
if not areCollinear(p.l, p.p, p.r) then
triangles[#triangles+1] = newPolygon(p.l.x,p.l.y, p.p.x,p.p.y, p.r.x,p.r.y)
skipped = 0
end
if concave[p.l] and ccw(adj[p.l].l, p.l, p.r) then
concave[p.l] = nil
end
if concave[p.r] and ccw(p.l, p.r, adj[p.r].r) then
concave[p.r] = nil
end
-- remove point from list
adj[p.p] = nil
adj[p.l].r = p.r
adj[p.r].l = p.l
nPoints = nPoints - 1
skipped = 0
p = adj[p.l]
else
p = adj[p.r]
skipped = skipped + 1
assert(skipped <= nPoints, "Cannot triangulate polygon (is the polygon intersecting itself?)")
end
end
if not areCollinear(p.l, p.p, p.r) then
triangles[#triangles+1] = newPolygon(p.l.x,p.l.y, p.p.x,p.p.y, p.r.x,p.r.y)
end
return triangles
end end
-- return merged polygon if possible or nil otherwise -- return merged polygon if possible or nil otherwise