HC/shapes.lua
Matthias Richter a9261b83fa Accomodate API change in love 0.10.0
love.graphics.point was replaced by love.graphics.points
2021-09-07 13:48:53 +02:00

469 lines
12 KiB
Lua

--[[
Copyright (c) 2011 Matthias Richter
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
Except as contained in this notice, the name(s) of the above copyright holders
shall not be used in advertising or otherwise to promote the sale, use or
other dealings in this Software without prior written authorization.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
]]--
local math_min, math_sqrt, math_huge = math.min, math.sqrt, math.huge
local _PACKAGE, common_local = (...):match("^(.+)%.[^%.]+"), common
if not (type(common) == 'table' and common.class and common.instance) then
assert(common_class ~= false, 'No class commons specification available.')
require(_PACKAGE .. '.class')
end
local vector = require(_PACKAGE .. '.vector-light')
local Polygon = require(_PACKAGE .. '.polygon')
local GJK = require(_PACKAGE .. '.gjk') -- actual collision detection
-- reset global table `common' (required by class commons)
if common_local ~= common then
common_local, common = common, common_local
end
--
-- base class
--
local Shape = {}
function Shape:init(t)
self._type = t
self._rotation = 0
end
function Shape:moveTo(x,y)
local cx,cy = self:center()
self:move(x - cx, y - cy)
end
function Shape:rotation()
return self._rotation
end
function Shape:rotate(angle)
self._rotation = self._rotation + angle
end
function Shape:setRotation(angle, x,y)
return self:rotate(angle - self._rotation, x,y)
end
--
-- class definitions
--
local ConvexPolygonShape = {}
function ConvexPolygonShape:init(polygon)
Shape.init(self, 'polygon')
assert(polygon:isConvex(), "Polygon is not convex.")
self._polygon = polygon
end
local ConcavePolygonShape = {}
function ConcavePolygonShape:init(poly)
Shape.init(self, 'compound')
self._polygon = poly
self._shapes = poly:splitConvex()
for i,s in ipairs(self._shapes) do
self._shapes[i] = common_local.instance(ConvexPolygonShape, s)
end
end
local CircleShape = {}
function CircleShape:init(cx,cy, radius)
Shape.init(self, 'circle')
self._center = {x = cx, y = cy}
self._radius = radius
end
local PointShape = {}
function PointShape:init(x,y)
Shape.init(self, 'point')
self._pos = {x = x, y = y}
end
--
-- collision functions
--
function ConvexPolygonShape:support(dx,dy)
local v = self._polygon.vertices
local max, vmax = -math_huge
for i = 1,#v do
local d = vector.dot(v[i].x,v[i].y, dx,dy)
if d > max then
max, vmax = d, v[i]
end
end
return vmax.x, vmax.y
end
function CircleShape:support(dx,dy)
return vector.add(self._center.x, self._center.y,
vector.mul(self._radius, vector.normalize(dx,dy)))
end
-- collision dispatching:
-- let circle shape or compund shape handle the collision
function ConvexPolygonShape:collidesWith(other)
if self == other then return false end
if other._type ~= 'polygon' then
local collide, sx,sy = other:collidesWith(self)
return collide, sx and -sx, sy and -sy
end
-- else: type is POLYGON
return GJK(self, other)
end
function ConcavePolygonShape:collidesWith(other)
if self == other then return false end
if other._type == 'point' then
return other:collidesWith(self)
end
-- TODO: better way of doing this. report all the separations?
local collide,dx,dy = false,0,0
for _,s in ipairs(self._shapes) do
local status, sx,sy = s:collidesWith(other)
collide = collide or status
if status then
if math.abs(dx) < math.abs(sx) then
dx = sx
end
if math.abs(dy) < math.abs(sy) then
dy = sy
end
end
end
return collide, dx, dy
end
function CircleShape:collidesWith(other)
if self == other then return false end
if other._type == 'circle' then
local px,py = self._center.x-other._center.x, self._center.y-other._center.y
local d = vector.len2(px,py)
local radii = self._radius + other._radius
if d < radii*radii then
-- if circles overlap, push it out upwards
if d == 0 then return true, 0,radii end
-- otherwise push out in best direction
return true, vector.mul(radii - math_sqrt(d), vector.normalize(px,py))
end
return false
elseif other._type == 'polygon' then
return GJK(self, other)
end
-- else: let the other shape decide
local collide, sx,sy = other:collidesWith(self)
return collide, sx and -sx, sy and -sy
end
function PointShape:collidesWith(other)
if self == other then return false end
if other._type == 'point' then
return (self._pos == other._pos), 0,0
end
return other:contains(self._pos.x, self._pos.y), 0,0
end
--
-- point location/ray intersection
--
function ConvexPolygonShape:contains(x,y)
return self._polygon:contains(x,y)
end
function ConcavePolygonShape:contains(x,y)
return self._polygon:contains(x,y)
end
function CircleShape:contains(x,y)
return vector.len2(x-self._center.x, y-self._center.y) < self._radius * self._radius
end
function PointShape:contains(x,y)
return x == self._pos.x and y == self._pos.y
end
function ConcavePolygonShape:intersectsRay(x,y, dx,dy)
return self._polygon:intersectsRay(x,y, dx,dy)
end
function ConvexPolygonShape:intersectsRay(x,y, dx,dy)
return self._polygon:intersectsRay(x,y, dx,dy)
end
function ConcavePolygonShape:intersectionsWithRay(x,y, dx,dy)
return self._polygon:intersectionsWithRay(x,y, dx,dy)
end
function ConvexPolygonShape:intersectionsWithRay(x,y, dx,dy)
return self._polygon:intersectionsWithRay(x,y, dx,dy)
end
-- circle intersection if distance of ray/center is smaller
-- than radius.
-- with r(s) = p + d*s = (x,y) + (dx,dy) * s defining the ray and
-- (x - cx)^2 + (y - cy)^2 = r^2, this problem is eqivalent to
-- solving [with c = (cx,cy)]:
--
-- d*d s^2 + 2 d*(p-c) s + (p-c)*(p-c)-r^2 = 0
function CircleShape:intersectionsWithRay(x,y, dx,dy)
local pcx,pcy = x-self._center.x, y-self._center.y
local a = vector.len2(dx,dy)
local b = 2 * vector.dot(dx,dy, pcx,pcy)
local c = vector.len2(pcx,pcy) - self._radius * self._radius
local discr = b*b - 4*a*c
if discr < 0 then return {} end
discr = math_sqrt(discr)
local ts, t1, t2 = {}, discr-b, -discr-b
if t1 >= 0 then ts[#ts+1] = t1/(2*a) end
if t2 >= 0 then ts[#ts+1] = t2/(2*a) end
return ts
end
function CircleShape:intersectsRay(x,y, dx,dy)
local tmin = math_huge
for _, t in ipairs(self:intersectionsWithRay(x,y,dx,dy)) do
tmin = math_min(t, tmin)
end
return tmin ~= math_huge, tmin
end
-- point shape intersects ray if it lies on the ray
function PointShape:intersectsRay(x,y, dx,dy)
local px,py = self._pos.x-x, self._pos.y-y
local t = px/dx
-- see (px,py) and (dx,dy) point in same direction
return (t == py/dy), t
end
function PointShape:intersectionsWithRay(x,y, dx,dy)
local intersects, t = self:intersectsRay(x,y, dx,dy)
return intersects and {t} or {}
end
--
-- auxiliary
--
function ConvexPolygonShape:center()
return self._polygon.centroid.x, self._polygon.centroid.y
end
function ConcavePolygonShape:center()
return self._polygon.centroid.x, self._polygon.centroid.y
end
function CircleShape:center()
return self._center.x, self._center.y
end
function PointShape:center()
return self._pos.x, self._pos.y
end
function ConvexPolygonShape:outcircle()
local cx,cy = self:center()
return cx,cy, self._polygon._radius
end
function ConcavePolygonShape:outcircle()
local cx,cy = self:center()
return cx,cy, self._polygon._radius
end
function CircleShape:outcircle()
local cx,cy = self:center()
return cx,cy, self._radius
end
function PointShape:outcircle()
return self._pos.x, self._pos.y, 0
end
function ConvexPolygonShape:bbox()
return self._polygon:bbox()
end
function ConcavePolygonShape:bbox()
return self._polygon:bbox()
end
function CircleShape:bbox()
local cx,cy = self:center()
local r = self._radius
return cx-r,cy-r, cx+r,cy+r
end
function PointShape:bbox()
local x,y = self:center()
return x,y,x,y
end
function ConvexPolygonShape:move(x,y)
self._polygon:move(x,y)
end
function ConcavePolygonShape:move(x,y)
self._polygon:move(x,y)
for _,p in ipairs(self._shapes) do
p:move(x,y)
end
end
function CircleShape:move(x,y)
self._center.x = self._center.x + x
self._center.y = self._center.y + y
end
function PointShape:move(x,y)
self._pos.x = self._pos.x + x
self._pos.y = self._pos.y + y
end
function ConcavePolygonShape:rotate(angle,cx,cy)
Shape.rotate(self, angle)
if not (cx and cy) then
cx,cy = self:center()
end
self._polygon:rotate(angle,cx,cy)
for _,p in ipairs(self._shapes) do
p:rotate(angle, cx,cy)
end
end
function ConvexPolygonShape:rotate(angle, cx,cy)
Shape.rotate(self, angle)
self._polygon:rotate(angle, cx, cy)
end
function CircleShape:rotate(angle, cx,cy)
Shape.rotate(self, angle)
if not (cx and cy) then return end
self._center.x,self._center.y = vector.add(cx,cy, vector.rotate(angle, self._center.x-cx, self._center.y-cy))
end
function PointShape:rotate(angle, cx,cy)
Shape.rotate(self, angle)
if not (cx and cy) then return end
self._pos.x,self._pos.y = vector.add(cx,cy, vector.rotate(angle, self._pos.x-cx, self._pos.y-cy))
end
function ConcavePolygonShape:scale(s)
assert(type(s) == "number" and s > 0, "Invalid argument. Scale must be greater than 0")
local cx,cy = self:center()
self._polygon:scale(s, cx,cy)
for _, p in ipairs(self._shapes) do
local dx,dy = vector.sub(cx,cy, p:center())
p:scale(s)
p:moveTo(cx-dx*s, cy-dy*s)
end
end
function ConvexPolygonShape:scale(s)
assert(type(s) == "number" and s > 0, "Invalid argument. Scale must be greater than 0")
self._polygon:scale(s, self:center())
end
function CircleShape:scale(s)
assert(type(s) == "number" and s > 0, "Invalid argument. Scale must be greater than 0")
self._radius = self._radius * s
end
function PointShape:scale()
-- nothing
end
function ConvexPolygonShape:draw(mode)
mode = mode or 'line'
love.graphics.polygon(mode, self._polygon:unpack())
end
function ConcavePolygonShape:draw(mode, wireframe)
local mode = mode or 'line'
if mode == 'line' then
love.graphics.polygon('line', self._polygon:unpack())
if not wireframe then return end
end
for _,p in ipairs(self._shapes) do
love.graphics.polygon(mode, p._polygon:unpack())
end
end
function CircleShape:draw(mode, segments)
local x, y, r = self:outcircle()
love.graphics.circle(mode or 'line', x, y, r, segments)
end
function PointShape:draw()
(love.graphics.points or love.graphics.point)(self:center())
end
Shape = common_local.class('Shape', Shape)
ConvexPolygonShape = common_local.class('ConvexPolygonShape', ConvexPolygonShape, Shape)
ConcavePolygonShape = common_local.class('ConcavePolygonShape', ConcavePolygonShape, Shape)
CircleShape = common_local.class('CircleShape', CircleShape, Shape)
PointShape = common_local.class('PointShape', PointShape, Shape)
local function newPolygonShape(polygon, ...)
-- create from coordinates if needed
if type(polygon) == "number" then
polygon = common_local.instance(Polygon, polygon, ...)
else
polygon = polygon:clone()
end
if polygon:isConvex() then
return common_local.instance(ConvexPolygonShape, polygon)
end
return common_local.instance(ConcavePolygonShape, polygon)
end
local function newCircleShape(...)
return common_local.instance(CircleShape, ...)
end
local function newPointShape(...)
return common_local.instance(PointShape, ...)
end
return {
ConcavePolygonShape = ConcavePolygonShape,
ConvexPolygonShape = ConvexPolygonShape,
CircleShape = CircleShape,
PointShape = PointShape,
newPolygonShape = newPolygonShape,
newCircleShape = newCircleShape,
newPointShape = newPointShape,
}