zprite/zchunk.lua
2025-07-19 11:02:00 -04:00

140 lines
3.4 KiB
Lua

local zprite = require("zprite.zprite")
---@class zchunk
---@field private _chunks {integer: {z: zprite, x: integer, y: integer}}
---@field private _chunk_size integer
---@field private _chunk_height integer
---@field private _chunk_wrap integer
---@field private _texture love.Image
---@field private _height_scale number
local zchunk = {}
zchunk.__index = zchunk
---@param texture love.Image
---@param chunk_size integer?
---@param chunk_height integer?
---@param chunk_wrap integer?
function zchunk.new(texture, chunk_size, chunk_height, chunk_wrap)
chunk_size = chunk_size or 16
chunk_height = chunk_height or 32
if chunk_size < 1 then
error("chunk size must be at least 1")
end
if chunk_height < 1 then
error("chunk height must be at least 1")
end
if chunk_wrap and chunk_wrap < 1 then
error("chunk wrap must be at least 1")
end
if not texture then
error("must have a texture")
end
local obj = setmetatable({}, zchunk)
obj._chunks = {}
obj._chunk_size = chunk_size
obj._chunk_height = chunk_height
obj._chunk_wrap = chunk_wrap
obj._texture = texture
obj._height_scale = 4
return obj
end
---@param x integer
---@param y integer
---@return integer
function zchunk:_chunk_index(x, y)
local cx = math.floor(x / self._chunk_size)
local cy = math.floor(y / self._chunk_size)
if self._chunk_wrap then
cx = cx % self._chunk_wrap
cy = cy % self._chunk_wrap
end
return cx + cy * 1e7
end
---@param x integer?
---@param y integer?
function zchunk:remove(x, y)
if not x then
self._chunks = {}
else
local index = self:_chunk_index(x, y)
self._chunks[index] = nil
end
end
---@param x integer?
---@param y integer?
function zchunk:clear(x, y)
if not x then
for _, chunk in pairs(self._chunks) do
chunk.z:clear()
end
else
local index = self:_chunk_index(x, y)
if not self._chunks[index] then
return
end
self._chunks[index].z:clear()
end
end
--- Add an 'entity' to be rendered
---@param x number
---@param y number
---@param quad love.Quad
---@param layer_count integer
---@param color_map fun(layer: integer): number, number, number
---@param base_layer integer?
function zchunk:put(x, y, quad, layer_count, color_map, base_layer)
local index = self:_chunk_index(x, y)
if not self._chunks[index] then
self._chunks[index] = {
z = zprite.new(self._texture, self._chunk_size * self._chunk_size * self._chunk_height),
}
self._chunks[index].z._height_scale = self._height_scale
end
self._chunks[index].z:put(x, y, quad, layer_count, color_map, base_layer)
self._chunks[index].x = math.floor(x / self._chunk_size)
self._chunks[index].y = math.floor(y / self._chunk_size)
end
local transform = love.math.newTransform()
local function sort_fn(a, b)
local _, ay_rotated = transform:transformPoint(a.x, a.y)
local _, by_rotated = transform:transformPoint(b.x, b.y)
return ay_rotated < by_rotated
end
--- Draw to the screen / current canvas
---@overload fun(self, x: number, y: number, r: number?, sx: number?, sy: number?, ox: number?, oy: number?, kx: number?, ky: number?)
---@overload fun(self, transform: love.Transform)
function zchunk:draw(x, y, r, ...)
local chunks = {}
for _, chunk in pairs(self._chunks) do
table.insert(chunks, chunk)
end
transform:reset()
if type(x) ~= "number" then
transform:apply(x)
else
transform:rotate(r and r or 0)
end
table.sort(chunks, sort_fn)
for _, chunk in ipairs(chunks) do
chunk.z:draw(x, y, r, ...)
end
end
return zchunk