light_world.lua/examples/vendor/sti/plugins/box2d.lua

350 lines
9.0 KiB
Lua
Executable File

--- Box2D plugin for STI
-- @module box2d
-- @author Landon Manning
-- @copyright 2015
-- @license MIT/X11
return {
box2d_LICENSE = "MIT/X11",
box2d_URL = "https://github.com/karai17/Simple-Tiled-Implementation",
box2d_VERSION = "2.3.2.1",
box2d_DESCRIPTION = "Box2D hooks for STI.",
--- Initialize Box2D physics world.
-- @param world The Box2D world to add objects to.
-- @return nil
box2d_init = function(map, world)
assert(love.physics, "To use the Box2D plugin, please enable the love.physics module.")
local body = love.physics.newBody(world, map.offsetx, map.offsety)
local collision = {
body = body,
}
local function convertEllipseToPolygon(x, y, w, h, max_segments)
local function calc_segments(segments)
local function vdist(a, b)
local c = {
x = a.x - b.x,
y = a.y - b.y,
}
return c.x * c.x + c.y * c.y
end
segments = segments or 64
local vertices = {}
local v = { 1, 2, math.ceil(segments/4-1), math.ceil(segments/4) }
local m
if love.physics then
m = love.physics.getMeter()
else
m = 32
end
for _, i in ipairs(v) do
local angle = (i / segments) * math.pi * 2
local px = x + w / 2 + math.cos(angle) * w / 2
local py = y + h / 2 + math.sin(angle) * h / 2
table.insert(vertices, { x = px / m, y = py / m })
end
local dist1 = vdist(vertices[1], vertices[2])
local dist2 = vdist(vertices[3], vertices[4])
-- Box2D threshold
if dist1 < 0.0025 or dist2 < 0.0025 then
return calc_segments(segments-2)
end
return segments
end
local segments = calc_segments(max_segments)
local vertices = {}
table.insert(vertices, { x = x + w / 2, y = y + h / 2 })
for i=0, segments do
local angle = (i / segments) * math.pi * 2
local px = x + w / 2 + math.cos(angle) * w / 2
local py = y + h / 2 + math.sin(angle) * h / 2
table.insert(vertices, { x = px, y = py })
end
return vertices
end
local function rotateVertex(v, x, y, cos, sin, oy)
oy = oy or 0
local vertex = {
x = v.x,
y = v.y - oy,
}
vertex.x = vertex.x - x
vertex.y = vertex.y - y
local vx = cos * vertex.x - sin * vertex.y
local vy = sin * vertex.x + cos * vertex.y
return vx + x, vy + y + oy
end
local function addObjectToWorld(objshape, vertices, userdata, object)
local shape
if objshape == "polyline" then
shape = love.physics.newChainShape(false, unpack(vertices))
else
shape = love.physics.newPolygonShape(unpack(vertices))
end
local fixture = love.physics.newFixture(body, shape)
fixture:setUserData(userdata)
if userdata.properties.sensor == "true" then
fixture:setSensor(true)
end
local obj = {
object = object,
shape = shape,
fixture = fixture,
}
table.insert(collision, obj)
end
local function getPolygonVertices(object)
local vertices = {}
for _, vertex in ipairs(object.polygon) do
table.insert(vertices, vertex.x)
table.insert(vertices, vertex.y)
end
return vertices
end
local function calculateObjectPosition(object, tile)
local o = {
shape = object.shape,
x = object.dx or object.x,
y = object.dy or object.y,
w = object.width,
h = object.height,
polygon = object.polygon or object.polyline or object.ellipse or object.rectangle
}
local userdata = {
object = o,
properties = object.properties
}
if o.shape == "rectangle" then
o.r = object.rotation or 0
local cos = math.cos(math.rad(o.r))
local sin = math.sin(math.rad(o.r))
local oy = 0
if object.gid then
local tileset = map.tilesets[map.tiles[object.gid].tileset]
local lid = object.gid - tileset.firstgid
local tile = {}
-- This fixes a height issue
o.y = o.y + map.tiles[object.gid].offset.y
oy = tileset.tileheight
for _, t in ipairs(tileset.tiles) do
if t.id == lid then
tile = t
break
end
end
if tile.objectGroup then
for _, obj in ipairs(tile.objectGroup.objects) do
-- Every object in the tile
calculateObjectPosition(obj, object)
end
return
else
o.w = map.tiles[object.gid].width
o.h = map.tiles[object.gid].height
end
end
o.polygon = {
{ x=o.x+0, y=o.y+0 },
{ x=o.x+o.w, y=o.y+0 },
{ x=o.x+o.w, y=o.y+o.h },
{ x=o.x+0, y=o.y+o.h },
}
for _, vertex in ipairs(o.polygon) do
if map.orientation == "isometric" then
vertex.x, vertex.y = map:convertIsometricToScreen(vertex.x, vertex.y)
end
vertex.x, vertex.y = rotateVertex(vertex, o.x, o.y, cos, sin, oy)
end
local vertices = getPolygonVertices(o)
addObjectToWorld(o.shape, vertices, userdata, tile or object)
elseif o.shape == "ellipse" then
if not o.polygon then
o.polygon = convertEllipseToPolygon(o.x, o.y, o.w, o.h)
end
local vertices = getPolygonVertices(o)
local triangles = love.math.triangulate(vertices)
for _, triangle in ipairs(triangles) do
addObjectToWorld(o.shape, triangle, userdata, tile or object)
end
elseif o.shape == "polygon" then
local vertices = getPolygonVertices(o)
local triangles = love.math.triangulate(vertices)
for _, triangle in ipairs(triangles) do
addObjectToWorld(o.shape, triangle, userdata, tile or object)
end
elseif o.shape == "polyline" then
local vertices = getPolygonVertices(o)
addObjectToWorld(o.shape, vertices, userdata, tile or object)
end
end
for _, tile in pairs(map.tiles) do
local tileset = map.tilesets[tile.tileset]
-- Every object in every instance of a tile
if tile.objectGroup then
if map.tileInstances[tile.gid] then
for _, instance in ipairs(map.tileInstances[tile.gid]) do
for _, object in ipairs(tile.objectGroup.objects) do
object.dx = object.x + instance.x
object.dy = object.y + instance.y
calculateObjectPosition(object, instance)
end
end
end
-- Every instance of a tile
elseif tile.properties and tile.properties.collidable == "true" and map.tileInstances[tile.gid] then
for _, instance in ipairs(map.tileInstances[tile.gid]) do
local object = {
shape = "rectangle",
x = instance.x,
y = instance.y,
width = tileset.tilewidth,
height = tileset.tileheight,
properties = tile.properties
}
calculateObjectPosition(object, instance)
end
end
end
for _, layer in ipairs(map.layers) do
-- Entire layer
if layer.properties.collidable == "true" then
if layer.type == "tilelayer" then
for gid, tiles in pairs(map.tileInstances) do
local tile = map.tiles[gid]
local tileset = map.tilesets[tile.tileset]
for _, instance in ipairs(tiles) do
if instance.layer == layer then
local object = {
shape = "rectangle",
x = instance.x,
y = instance.y,
width = tileset.tilewidth,
height = tileset.tileheight,
properties = tile.properties
}
calculateObjectPosition(object, instance)
end
end
end
elseif layer.type == "objectgroup" then
for _, object in ipairs(layer.objects) do
calculateObjectPosition(object)
end
elseif layer.type == "imagelayer" then
local object = {
shape = "rectangle",
x = layer.x or 0,
y = layer.y or 0,
width = layer.width,
height = layer.height,
properties = layer.properties
}
calculateObjectPosition(object)
end
end
-- Individual objects
if layer.type == "objectgroup" then
for _, object in ipairs(layer.objects) do
if object.properties.collidable == "true" then
calculateObjectPosition(object)
end
end
end
end
map.box2d_collision = collision
end,
--- Remove Box2D fixtures and shapes from world.
-- @param index The index or name of the layer being removed
-- @return nil
box2d_removeLayer = function(map, index)
local layer = assert(map.layers[index], "Layer not found: " .. index)
local collision = map.box2d_collision
-- Remove collision objects
for i=#collision, 1, -1 do
local obj = collision[i]
if obj.object.layer == layer then
obj.fixture:destroy()
table.remove(collision, i)
end
end
end,
--- Draw Box2D physics world.
-- @return nil
box2d_draw = function(map)
local collision = map.box2d_collision
for _, obj in ipairs(collision) do
local points = {collision.body:getWorldPoints(obj.shape:getPoints())}
if #points == 4 then
love.graphics.line(points)
else
love.graphics.polygon("line", points)
end
end
end,
}
--- Custom Properties in Tiled are used to tell this plugin what to do.
-- @table Properties
-- @field collidable set to "true", can be used on any Layer, Tile, or Object
-- @field sensor set to "true", can be used on any Tile or Object that is also collidable