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imgui-luau/imgui/backend/imgui_impl_roblox.lua
T
2026-10-07 15:12:59 -05:00

754 lines
34 KiB
Lua

--- ImGui Backend for Roblox
--- - Renderer: exact software rasterizer (1:1 with imgui's triangles) into 256x256 EditableImage tiles at native
--- screen resolution; only tiles whose content changed are redrawn/uploaded (see RenderDrawData).
--- - Platform: UserInputService
--- - Files: an in-memory file system (VFS), pre-filled with the fonts from imgui_impl_roblox_fonts.lua
--- Requires "Allow Mesh / Image APIs" (EditableImage) in game settings.
local UserInputService = game:GetService("UserInputService")
local Players = game:GetService("Players")
local AssetService = game:GetService("AssetService")
local floor, ceil, min, max = math.floor, math.ceil, math.min, math.max
local readu8, readu32, writeu32, readstring = buffer.readu8, buffer.readu32, buffer.writeu32, buffer.readstring
local band, rshift = bit32.band, bit32.rshift
local ImGui_ImplRoblox_GetBackendData
local ImGui_ImplRoblox_UpdateTexture
local ImGui_ImplRoblox_RenderDrawData
local ImGui_ImplRoblox_Shutdown
local KEY_MAP = {} -- Enum.KeyCode -> ImGuiKey
do
local names = {
Return = "Enter", Escape = "Escape", Backspace = "Backspace", Tab = "Tab", Space = "Space", KeypadEnter = "KeypadEnter",
Up = "UpArrow", Down = "DownArrow", Left = "LeftArrow", Right = "RightArrow",
Home = "Home", End = "End", PageUp = "PageUp", PageDown = "PageDown", Insert = "Insert", Delete = "Delete",
LeftControl = "LeftCtrl", RightControl = "RightCtrl", LeftShift = "LeftShift", RightShift = "RightShift",
LeftAlt = "LeftAlt", RightAlt = "RightAlt", LeftSuper = "LeftSuper", RightSuper = "RightSuper",
Quote = "Apostrophe", Comma = "Comma", Minus = "Minus", Period = "Period", Slash = "Slash", Semicolon = "Semicolon",
Equals = "Equal", LeftBracket = "LeftBracket", BackSlash = "Backslash", RightBracket = "RightBracket", Backquote = "GraveAccent",
CapsLock = "CapsLock",
KeypadPeriod = "KeypadDecimal", KeypadDivide = "KeypadDivide", KeypadMultiply = "KeypadMultiply",
KeypadMinus = "KeypadSubtract", KeypadPlus = "KeypadAdd", KeypadEquals = "KeypadEqual",
}
local digits = { "Zero", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine" }
for i = 0, 9 do
names[digits[i + 1]] = "K" .. i
names["Keypad" .. digits[i + 1]] = "Keypad" .. i
end
for i = 1, 12 do names["F" .. i] = "F" .. i end
for c in ("ABCDEFGHIJKLMNOPQRSTUVWXYZ"):gmatch(".") do names[c] = c end
for rbx_name, imgui_name in pairs(names) do
KEY_MAP[Enum.KeyCode[rbx_name]] = ImGuiKey[imgui_name]
end
end
-- Roblox has no "text input" event, so characters come from KeyCode.Value (ASCII for printable keys) + a US layout shift table.
local SHIFTED = {
["1"] = "!", ["2"] = "@", ["3"] = "#", ["4"] = "$", ["5"] = "%", ["6"] = "^", ["7"] = "&", ["8"] = "*", ["9"] = "(", ["0"] = ")",
["-"] = "_", ["="] = "+", ["["] = "{", ["]"] = "}", ["\\"] = "|", [";"] = ":", ["'"] = "\"", [","] = "<", ["."] = ">", ["/"] = "?", ["`"] = "~",
}
local MOUSE_BUTTONS = {
[Enum.UserInputType.MouseButton1] = 0, -- ImGuiMouseButton.Left
[Enum.UserInputType.MouseButton2] = 1, -- ImGuiMouseButton.Right
[Enum.UserInputType.MouseButton3] = 2, -- ImGuiMouseButton.Middle
}
--- @return boolean ctrl, boolean shift, boolean alt
local function ImGui_ImplRoblox_UpdateKeyModifiers()
local io = ImGui.GetIO()
local K = Enum.KeyCode
local ctrl = UserInputService:IsKeyDown(K.LeftControl) or UserInputService:IsKeyDown(K.RightControl)
local shift = UserInputService:IsKeyDown(K.LeftShift) or UserInputService:IsKeyDown(K.RightShift)
local alt = UserInputService:IsKeyDown(K.LeftAlt) or UserInputService:IsKeyDown(K.RightAlt)
io:AddKeyEvent(ImGuiMod_Ctrl, ctrl)
io:AddKeyEvent(ImGuiMod_Shift, shift)
io:AddKeyEvent(ImGuiMod_Alt, alt)
io:AddKeyEvent(ImGuiMod_Super, UserInputService:IsKeyDown(K.LeftSuper) or UserInputService:IsKeyDown(K.RightSuper))
return ctrl, shift, alt
end
--- @return table?
function ImGui_ImplRoblox_GetBackendData()
return ImGui.GetCurrentContext() and ImGui.GetIO().BackendPlatformUserData or nil
end
local function ImGui_ImplRoblox_UpdateMonitors(w, h)
local platform_io = ImGui.GetPlatformIO()
platform_io.Monitors:resize(0)
local imgui_monitor = ImGuiPlatformMonitor()
ImVec2_Copy(imgui_monitor.MainSize, ImVec2(w, h))
ImVec2_Copy(imgui_monitor.WorkSize, ImVec2(w, h))
platform_io.Monitors:push_back(imgui_monitor)
end
---------------------------------------------------------
-- PLATFORM DATA & CALLBACKS
---------------------------------------------------------
-- Games can't touch the OS clipboard, so copy/paste only works inside ImGui
local clipboard = ""
local function ImGui_ImplRoblox_PlatformSetClipboardText(ctx, text) clipboard = text end
local function ImGui_ImplRoblox_PlatformGetClipboardText(ctx) return clipboard end
---------------------------------------------------------
-- FILE SYSTEM (in-memory, Roblox has no file access)
---------------------------------------------------------
local VFS = {} -- path -> string of raw bytes
--- Registers a file so ImGui can load it, e.g. ImGui_ImplRoblox.AddFile("fonts/MyFont.ttf", bytes)
--- then io.Fonts:AddFontFromFileTTF("fonts/MyFont.ttf", 16)
local function ImGui_ImplRoblox_AddFile(path, bytes) VFS[path] = bytes end
for path, hex in pairs(IM_INCLUDE("imgui_impl_roblox_fonts.lua")) do
VFS[path] = hex:gsub("%s", ""):gsub("%x%x", function(h) return string.char(tonumber(h, 16)) end)
end
function ImStd.ImFileOpen(filename, mode)
local data = VFS[filename]
return data and { Data = data, Pos = 0 } or nil
end
function ImStd.ImFileClose(f) end
function ImStd.ImFileGetSize(f) return #f.Data end
function ImStd.ImFileRead(f, data, count)
local s, pos = f.Data, f.Pos
count = min(count, #s - pos)
for i = 1, count do data[i] = string.byte(s, pos + i) end
f.Pos = pos + count
return count
end
function ImStd.ImFileLoadToMemory(filename, mode)
local f = ImStd.ImFileOpen(filename, mode)
if not f or #f.Data == 0 then return end
local file_data = {}
local size = ImStd.ImFileRead(f, file_data, #f.Data)
return file_data, size
end
---------------------------------------------------------
-- TEXTURE MANAGEMENT
---------------------------------------------------------
-- Copies a region of ImTextureData pixels (1-based byte table) into our RGBA8 buffer
local function CopyTexturePixels(tex, dst, x, y, w, h)
local bpp, tex_w = tex.BytesPerPixel, tex.Width
for row = 0, h - 1 do
local src, src_base = tex:GetPixelsAt(x, y + row)
local dst_off = ((y + row) * tex_w + x) * 4
if bpp == 4 then
for i = 0, w - 1 do
local s = src_base + i * 4
writeu32(dst, dst_off + i * 4, src[s] + src[s + 1] * 256 + src[s + 2] * 65536 + src[s + 3] * 16777216)
end
else -- Alpha8: white with alpha
for i = 0, w - 1 do
writeu32(dst, dst_off + i * 4, 16777215 + src[src_base + i] * 16777216)
end
end
end
end
function ImGui_ImplRoblox_UpdateTexture(tex)
local bd = ImGui_ImplRoblox_GetBackendData()
if tex.Status == ImTextureStatus.WantCreate then
local t = { Buffer = buffer.create(tex.Width * tex.Height * 4), Width = tex.Width, Height = tex.Height }
CopyTexturePixels(tex, t.Buffer, 0, 0, tex.Width, tex.Height)
bd.TextureCount = bd.TextureCount + 1
bd.Textures[bd.TextureCount] = t
tex.BackendUserData = bd.TextureCount
tex:SetTexID(bd.TextureCount)
tex:SetStatus(ImTextureStatus.OK)
elseif tex.Status == ImTextureStatus.WantUpdates then
local t = bd.Textures[tex.BackendUserData]
IM_ASSERT(t ~= nil)
for _, r in tex.Updates:iter() do
CopyTexturePixels(tex, t.Buffer, r.x, r.y, r.w, r.h)
end
tex:SetStatus(ImTextureStatus.OK)
elseif tex.Status == ImTextureStatus.WantDestroy then
if tex.BackendUserData then
bd.Textures[tex.BackendUserData] = nil
tex.BackendUserData = nil
end
tex:SetTexID(ImTextureID_Invalid)
tex:SetStatus(ImTextureStatus.Destroyed)
end
end
---------------------------------------------------------
-- RENDERING (software rasterizer into tile buffers)
---------------------------------------------------------
-- Buffer layout: 4 bytes per pixel, R G B A, row-major, 0-based offsets. ImU32 colours are already R | G<<8 | B<<16 | A<<24.
-- Blending is non-premultiplied "over" with a transparent (alpha 0) background, so the game stays visible behind ImGui.
local buf, buf_w -- buffer/width of the tile being drawn
local TILE_SIZE -- Vector2, set below
-- Blends one pixel (r, g, b, a are 0..255). One u32 read/write, one division in the general case.
-- FillSpan below inlines the same math with per-span constants - keep the two in sync.
local function BlendPixel(o, r, g, b, a)
if a >= 255 then
writeu32(buf, o, floor(r + 0.5) + floor(g + 0.5) * 256 + floor(b + 0.5) * 65536 + 4278190080)
return
end
if a <= 0 then return end
local d = readu32(buf, o)
local da = rshift(d, 24)
if da == 0 then
writeu32(buf, o, floor(r + 0.5) + floor(g + 0.5) * 256 + floor(b + 0.5) * 65536 + floor(a + 0.5) * 16777216)
return
end
local sa = a / 255
local dr, dg, db = band(d, 255), band(rshift(d, 8), 255), band(rshift(d, 16), 255)
if da == 255 then
local ns = 1 - sa
writeu32(buf, o, floor(r * sa + dr * ns + 0.5) + floor(g * sa + dg * ns + 0.5) * 256 + floor(b * sa + db * ns + 0.5) * 65536 + 4278190080)
else
local k = da * ((1 - sa) / 255)
local oa = sa + k
local inv = 1 / oa
writeu32(buf, o, floor((r * sa + dr * k) * inv + 0.5) + floor((g * sa + dg * k) * inv + 0.5) * 256
+ floor((b * sa + db * k) * inv + 0.5) * 65536 + floor(oa * 255 + 0.5) * 16777216)
end
end
-- Fills pixels [x0, x1) of row y with one colour
local function FillSpan(y, x0, x1, r, g, b, a)
if a <= 0 then return end
local o0 = (y * buf_w + x0) * 4
local o1 = o0 + (x1 - x0 - 1) * 4
if a >= 255 then
local packed = floor(r + 0.5) + floor(g + 0.5) * 256 + floor(b + 0.5) * 65536 + 4278190080
for o = o0, o1, 4 do writeu32(buf, o, packed) end
return
end
local packed0 = floor(r + 0.5) + floor(g + 0.5) * 256 + floor(b + 0.5) * 65536 + floor(a + 0.5) * 16777216
local sa = a / 255
local ns = 1 - sa
local c1 = ns / 255
local rs, gs, bs = r * sa, g * sa, b * sa
local last_d, last_v = -1, 0 -- UI backgrounds are mostly flat: reuse the previous result for the same destination
for o = o0, o1, 4 do
local d = readu32(buf, o)
local da = rshift(d, 24)
if d == last_d then
writeu32(buf, o, last_v)
elseif da == 0 then
writeu32(buf, o, packed0)
else
last_d = d
local dr, dg, db = band(d, 255), band(rshift(d, 8), 255), band(rshift(d, 16), 255)
if da == 255 then
last_v = floor(rs + dr * ns + 0.5) + floor(gs + dg * ns + 0.5) * 256 + floor(bs + db * ns + 0.5) * 65536 + 4278190080
else
local k = da * c1
local oa = sa + k
local inv = 1 / oa
last_v = floor((rs + dr * k) * inv + 0.5) + floor((gs + dg * k) * inv + 0.5) * 256
+ floor((bs + db * k) * inv + 0.5) * 65536 + floor(oa * 255 + 0.5) * 16777216
end
writeu32(buf, o, last_v)
end
end
end
local function UnpackColor(col)
return col % 256, floor(col / 256) % 256, floor(col / 65536) % 256, floor(col / 16777216) % 256
end
-- Nearest texel at (u, v) as r, g, b, a (0..255)
local function SampleTexture(t, u, v)
local tw, th = t.Width, t.Height
local tx, ty = floor(u * tw), floor(v * th)
if tx < 0 then tx = 0 elseif tx >= tw then tx = tw - 1 end
if ty < 0 then ty = 0 elseif ty >= th then ty = th - 1 end
local o = (ty * tw + tx) * 4
local tb = t.Buffer
return readu8(tb, o), readu8(tb, o + 1), readu8(tb, o + 2), readu8(tb, o + 3)
end
-- Axis aligned, single colour quad (rects, glyphs, images). Pixel centers inside [x0, x1) x [y0, y1) are drawn.
local function DrawRect(x0, y0, x1, y1, u0, v0, u1, v1, col, t, cx0, cy0, cx1, cy1)
local r, g, b, a = UnpackColor(col)
if a == 0 then return end
local px0, py0 = max(ceil(x0 - 0.5), cx0), max(ceil(y0 - 0.5), cy0)
local px1, py1 = min(ceil(x1 - 0.5), cx1), min(ceil(y1 - 0.5), cy1)
if px0 >= px1 or py0 >= py1 then return end
if not t or (u0 == u1 and v0 == v1) then
if t then
local tr, tg, tb, ta = SampleTexture(t, u0, v0)
r, g, b, a = r * tr / 255, g * tg / 255, b * tb / 255, a * ta / 255
end
if a <= 0 then return end
-- Rows of a flat rect usually blend over identical rows: when this row's destination equals the previous
-- row's (exact string compare), the result is identical too, so memcpy the previous row's result.
local len = (px1 - px0) * 4
local prev_dst, prev_o = nil, 0
for y = py0, py1 - 1 do
local o = (y * buf_w + px0) * 4
if a >= 255 then
if prev_dst then buffer.copy(buf, o, buf, prev_o, len) else FillSpan(y, px0, px1, r, g, b, a); prev_dst = true end
else
local dst = readstring(buf, o, len)
if dst == prev_dst then
buffer.copy(buf, o, buf, prev_o, len)
else
FillSpan(y, px0, px1, r, g, b, a)
prev_dst = dst
end
end
prev_o = o
end
return
end
local du, dv = (u1 - u0) / (x1 - x0), (v1 - v0) / (y1 - y0)
local tw, th, tbuf = t.Width, t.Height, t.Buffer
local r255, g255, b255, a255 = r / 255, g / 255, b / 255, a / 255
for y = py0, py1 - 1 do
local ty = floor((v0 + (y + 0.5 - y0) * dv) * th)
if ty < 0 then ty = 0 elseif ty >= th then ty = th - 1 end
local trow = ty * tw
local o = (y * buf_w + px0) * 4
for x = px0, px1 - 1 do
local tx = floor((u0 + (x + 0.5 - x0) * du) * tw)
if tx < 0 then tx = 0 elseif tx >= tw then tx = tw - 1 end
local to = (trow + tx) * 4
local ta = readu8(tbuf, to + 3)
if ta > 0 then
BlendPixel(o, readu8(tbuf, to) * r255, readu8(tbuf, to + 1) * g255, readu8(tbuf, to + 2) * b255, ta * a255)
end
o = o + 4
end
end
end
-- Generic triangle: per-vertex colour + uv, top-left fill rule, clipped to [cx0, cx1) x [cy0, cy1)
local function DrawTriangle(va, vb, vc, t, cx0, cy0, cx1, cy1, ox, oy)
local x0, y0 = va[1][1] - ox, va[1][2] - oy
local x1, y1 = vb[1][1] - ox, vb[1][2] - oy
local x2, y2 = vc[1][1] - ox, vc[1][2] - oy
local area = (x1 - x0) * (y2 - y0) - (y1 - y0) * (x2 - x0)
if area == 0 then return end
if area < 0 then -- make the winding consistent so "inside" means all edge functions >= 0
vb, vc = vc, vb
x1, y1, x2, y2 = x2, y2, x1, y1
area = -area
end
local minx, maxx = max(floor(min(x0, x1, x2)), cx0), min(ceil(max(x0, x1, x2)), cx1 - 1)
local miny, maxy = max(floor(min(y0, y1, y2)), cy0), min(ceil(max(y0, y1, y2)), cy1 - 1)
if minx > maxx or miny > maxy then return end
-- Edge functions E(p) = A*px + B*py + C, w0 is opposite va, w1 opposite vb, w2 opposite vc
local A0, B0 = y1 - y2, x2 - x1; local C0 = -(A0 * x1 + B0 * y1)
local A1, B1 = y2 - y0, x0 - x2; local C1 = -(A1 * x2 + B1 * y2)
local A2, B2 = y0 - y1, x1 - x0; local C2 = -(A2 * x0 + B2 * y0)
local tl0 = A0 > 0 or (A0 == 0 and B0 > 0)
local tl1 = A1 > 0 or (A1 == 0 and B1 > 0)
local tl2 = A2 > 0 or (A2 == 0 and B2 > 0)
local inv = 1 / area
local ra, ga, ba, aa = UnpackColor(va[3])
local rb, gb, bb, ab = UnpackColor(vb[3])
local rc, gc, bc, ac = UnpackColor(vc[3])
local ua, vva, ub, vvb, uc, vvc = va[2][1], va[2][2], vb[2][1], vb[2][2], vc[2][1], vc[2][2]
local textured = t and not (ua == ub and ua == uc and vva == vvb and vva == vvc)
if t and not textured then -- constant uv (e.g. the atlas white pixel): fold the texel into the vertex colours
local tr, tg, tb, ta = SampleTexture(t, ua, vva)
ra, ga, ba, aa = ra * tr / 255, ga * tg / 255, ba * tb / 255, aa * ta / 255
rb, gb, bb, ab = rb * tr / 255, gb * tg / 255, bb * tb / 255, ab * ta / 255
rc, gc, bc, ac = rc * tr / 255, gc * tg / 255, bc * tb / 255, ac * ta / 255
end
local flat = not textured and ra == rb and ra == rc and ga == gb and ga == gc and ba == bb and ba == bc and aa == ab and aa == ac
if flat and aa <= 0 then return end
for y = miny, maxy do
local py = y + 0.5
-- Narrow the x range of this row using the edges (expanded by one pixel, exact test below)
local xl, xr = minx, maxx
local e0, e1, e2 = B0 * py + C0, B1 * py + C1, B2 * py + C2
if A0 ~= 0 then local xe = -e0 / A0 - 0.5; if A0 > 0 then xl = max(xl, floor(xe)) else xr = min(xr, ceil(xe)) end end
if A1 ~= 0 then local xe = -e1 / A1 - 0.5; if A1 > 0 then xl = max(xl, floor(xe)) else xr = min(xr, ceil(xe)) end end
if A2 ~= 0 then local xe = -e2 / A2 - 0.5; if A2 > 0 then xl = max(xl, floor(xe)) else xr = min(xr, ceil(xe)) end end
local row = y * buf_w
for x = xl, xr do
local px = x + 0.5
local w0, w1, w2 = A0 * px + e0, A1 * px + e1, A2 * px + e2
if (w0 > 0 or (w0 == 0 and tl0)) and (w1 > 0 or (w1 == 0 and tl1)) and (w2 > 0 or (w2 == 0 and tl2)) then
local o = (row + x) * 4
if flat then
BlendPixel(o, ra, ga, ba, aa)
else
w0, w1, w2 = w0 * inv, w1 * inv, w2 * inv
local r = w0 * ra + w1 * rb + w2 * rc
local g = w0 * ga + w1 * gb + w2 * gc
local b = w0 * ba + w1 * bb + w2 * bc
local a = w0 * aa + w1 * ab + w2 * ac
if textured then
local tr, tg, tb, ta = SampleTexture(t, w0 * ua + w1 * ub + w2 * uc, w0 * vva + w1 * vvb + w2 * vvc)
r, g, b, a = r * tr / 255, g * tg / 255, b * tb / 255, a * ta / 255
end
BlendPixel(o, r, g, b, a)
end
end
end
end
end
-- Quads emitted by PrimRect/PrimRectUV/RenderText use indices (a, b, c, a, c, d) with a=TL, b=TR, c=BR, d=BL.
-- When such a quad is axis aligned with one colour it is drawn with the much cheaper DrawRect.
local function TryDrawRect(va, vb, vc, vd, t, cx0, cy0, cx1, cy1, ox, oy)
local pa, pb, pc, pd = va[1], vb[1], vc[1], vd[1]
if not (pa[2] == pb[2] and pb[1] == pc[1] and pc[2] == pd[2] and pd[1] == pa[1] and pa[1] < pb[1] and pa[2] < pd[2]) then return false end
local col = va[3]
if vb[3] ~= col or vc[3] ~= col or vd[3] ~= col then return false end
local ta, tb, tc, td = va[2], vb[2], vc[2], vd[2]
if not (tb[1] == tc[1] and tb[2] == ta[2] and td[1] == ta[1] and td[2] == tc[2]) then return false end
DrawRect(pa[1] - ox, pa[2] - oy, pc[1] - ox, pc[2] - oy, ta[1], ta[2], tc[1], tc[2], col, t, cx0, cy0, cx1, cy1)
return true
end
-- Tiles: the screen is covered by TILE x TILE EditableImages (one ImageLabel each). Every frame each primitive
-- (triangle, or axis aligned quad) is hashed into the tiles it touches; only tiles whose hash changed are
-- re-rasterized and uploaded. Static UI therefore costs ~nothing to draw, and the result is pixel-identical to a
-- full redraw (the hash covers everything that affects a tile's pixels: geometry, uv, colour, texture, clip, order).
local TILE = 256
TILE_SIZE = Vector2.new(TILE, TILE)
local P1, P2 = 2147483647, 2147483629 -- two independent 31 bit hashes per tile (collision odds ~2^-62)
-- Primitive arrays (reused between frames, no per-frame allocation)
local pr_a, pr_b, pr_c, pr_d, pr_t = {}, {}, {}, {}, {} -- vertices (pr_d == false -> triangle), texture
local pr_cx0, pr_cy0, pr_cx1, pr_cy1 = {}, {}, {}, {} -- clip (screen pixels)
local function HashVertex(h1, h2, v)
local p, u, c = v[1], v[2], v[3]
local x, y = p[1], p[2]
local uv = u[1] * 8192 + u[2]
h1 = (h1 * 48271 + x * 4096 + y) % P1
h1 = (h1 * 48271 + uv * 4096) % P1
h1 = (h1 * 48271 + c) % P1
h2 = (h2 * 16807 + y * 4093 + x) % P2
h2 = (h2 * 16807 + uv * 65521) % P2
h2 = (h2 * 16807 + c) % P2
return h1, h2
end
local function GetTile(bd, index, tx, ty)
local tile = bd.Tiles[index]
if tile then return tile end
local img = AssetService:CreateEditableImage({ Size = Vector2.new(TILE, TILE) })
assert(img, "imgui_impl_roblox: EditableImage memory budget exceeded")
local label = Instance.new("ImageLabel")
label.Name = "Tile" .. index
label.BackgroundTransparency = 1
label.BorderSizePixel = 0
label.Size = UDim2.fromOffset(TILE, TILE)
label.Position = UDim2.fromOffset(tx * TILE, ty * TILE)
label.ResampleMode = Enum.ResamplerMode.Pixelated
label.ImageContent = Content.fromObject(img)
label.Visible = false
label.Parent = bd.Gui
tile = { Image = img, Label = label, Buffer = buffer.create(TILE * TILE * 4), H1 = -1, H2 = -1, Visible = false }
bd.Tiles[index] = tile
return tile
end
local function DestroyTiles(bd)
for _, tile in pairs(bd.Tiles) do tile.Label:Destroy(); tile.Image:Destroy() end
bd.Tiles = {}
end
function ImGui_ImplRoblox_RenderDrawData(draw_data)
local bd = ImGui_ImplRoblox_GetBackendData()
if draw_data.Textures ~= nil then
for _, tex in draw_data.Textures:iter() do
if tex.Status ~= ImTextureStatus.OK then
ImGui_ImplRoblox_UpdateTexture(tex)
bd.ForceRedraw = true -- texture contents changed: tiles sampling it must be redrawn
end
end
end
local sw, sh = floor(draw_data.DisplaySize.x), floor(draw_data.DisplaySize.y)
if sw <= 0 or sh <= 0 then return end
local cols, rows = ceil(sw / TILE), ceil(sh / TILE)
if cols ~= bd.TileCols or rows ~= bd.TileRows then
DestroyTiles(bd)
bd.TileCols, bd.TileRows = cols, rows
end
local ntiles = cols * rows
local ox, oy = draw_data.DisplayPos.x, draw_data.DisplayPos.y
-- Per tile: hashes and the list of primitives touching it
local th1, th2, tn, tl = bd.TH1, bd.TH2, bd.TN, bd.TL
for t = 0, ntiles - 1 do
th1[t], th2[t], tn[t] = 0, 0, 0
if not tl[t] then tl[t] = {} end
end
-- Pass 1: collect primitives, hash them into tiles
local n = 0
for _, draw_list in draw_data.CmdLists:iter() do
local vtx, idx = draw_list.VtxBuffer.Data, draw_list.IdxBuffer.Data
for _, pcmd in draw_list.CmdBuffer:iter() do
if pcmd.UserCallback ~= nil then
pcmd.UserCallback(draw_list, pcmd)
elseif pcmd.ElemCount > 0 then
local clip = pcmd.ClipRect
local cx0, cy0 = max(floor(clip.x - ox), 0), max(floor(clip.y - oy), 0)
local cx1, cy1 = min(floor(clip.z - ox), sw), min(floor(clip.w - oy), sh)
if cx1 > cx0 and cy1 > cy0 then
local tex_id = pcmd:GetTexID()
local t = bd.Textures[tex_id]
local ch1 = ((cx0 * 8191 + cy0) * 8191 + cx1) % P1
local ch2 = ((cy1 * 8191 + cx1) * 8191 + cy0 + tex_id) % P2
local vo = pcmd.VtxOffset
local i, last = pcmd.IdxOffset + 1, pcmd.IdxOffset + pcmd.ElemCount
while i <= last do
local ia, ic = idx[i], idx[i + 2]
local va, vb, vc = vtx[vo + ia], vtx[vo + idx[i + 1]], vtx[vo + ic]
local vd = false
local pa, pb, pc = va[1], vb[1], vc[1]
local bx0, by0, bx1, by1
if i + 5 <= last and idx[i + 3] == ia and idx[i + 4] == ic then
local d = vtx[vo + idx[i + 5]]
local pd = d[1]
-- axis aligned quad (TL, TR, BR, BL) with one colour and a matching uv rect
if pa[2] == pb[2] and pb[1] == pc[1] and pc[2] == pd[2] and pd[1] == pa[1] and pa[1] < pb[1] and pa[2] < pd[2] then
local col = va[3]
local ta, tb, tc, td = va[2], vb[2], vc[2], d[2]
if vb[3] == col and vc[3] == col and d[3] == col
and tb[1] == tc[1] and tb[2] == ta[2] and td[1] == ta[1] and td[2] == tc[2] then
vd = d
bx0, by0 = ceil(pa[1] - ox - 0.5), ceil(pa[2] - oy - 0.5)
bx1, by1 = ceil(pc[1] - ox - 0.5), ceil(pc[2] - oy - 0.5)
end
end
end
if vd then
i = i + 6
else
bx0, by0 = floor(min(pa[1], pb[1], pc[1]) - ox), floor(min(pa[2], pb[2], pc[2]) - oy)
bx1, by1 = ceil(max(pa[1], pb[1], pc[1]) - ox) + 1, ceil(max(pa[2], pb[2], pc[2]) - oy) + 1
i = i + 3
end
if bx0 < cx0 then bx0 = cx0 end
if by0 < cy0 then by0 = cy0 end
if bx1 > cx1 then bx1 = cx1 end
if by1 > cy1 then by1 = cy1 end
if bx0 < bx1 and by0 < by1 then
n = n + 1
pr_a[n], pr_b[n], pr_c[n], pr_d[n], pr_t[n] = va, vb, vc, vd, t
pr_cx0[n], pr_cy0[n], pr_cx1[n], pr_cy1[n] = cx0, cy0, cx1, cy1
local h1, h2 = HashVertex(ch1, ch2, va)
h1, h2 = HashVertex(h1, h2, vb)
h1, h2 = HashVertex(h1, h2, vc)
if vd then h1, h2 = HashVertex(h1, h2, vd) end
for ty = floor(by0 / TILE), floor((by1 - 1) / TILE) do
for tx = floor(bx0 / TILE), floor((bx1 - 1) / TILE) do
local ti = ty * cols + tx
local k = tn[ti] + 1
tn[ti] = k
tl[ti][k] = n
th1[ti] = (th1[ti] * 48271 + h1) % P1
th2[ti] = (th2[ti] * 16807 + h2 + k) % P2
end
end
end
end
end
end
end
end
-- Pass 2: redraw + upload changed tiles
local force = bd.ForceRedraw
bd.ForceRedraw = false
for ty = 0, rows - 1 do
for tx = 0, cols - 1 do
local ti = ty * cols + tx
local count = tn[ti]
local tile = bd.Tiles[ti]
if count == 0 then
if tile and tile.Visible then
tile.Visible = false
tile.Label.Visible = false
tile.H1 = -1
end
else
tile = tile or GetTile(bd, ti, tx, ty)
if force or tile.H1 ~= th1[ti] or tile.H2 ~= th2[ti] then
tile.H1, tile.H2 = th1[ti], th2[ti]
local x0, y0 = tx * TILE, ty * TILE
local x1, y1 = x0 + TILE, y0 + TILE
buf, buf_w = tile.Buffer, TILE
buffer.fill(buf, 0, 0)
local list = tl[ti]
local tox, toy = ox + x0, oy + y0
for k = 1, count do
local p = list[k]
local cx0, cy0 = max(pr_cx0[p], x0) - x0, max(pr_cy0[p], y0) - y0
local cx1, cy1 = min(pr_cx1[p], x1) - x0, min(pr_cy1[p], y1) - y0
local va, vc, vd = pr_a[p], pr_c[p], pr_d[p]
if vd then
local pa, pc, ta, tc = va[1], vc[1], va[2], vc[2]
DrawRect(pa[1] - tox, pa[2] - toy, pc[1] - tox, pc[2] - toy, ta[1], ta[2], tc[1], tc[2], va[3], pr_t[p], cx0, cy0, cx1, cy1)
else
DrawTriangle(va, pr_b[p], vc, pr_t[p], cx0, cy0, cx1, cy1, tox, toy)
end
end
tile.Image:WritePixelsBuffer(Vector2.zero, TILE_SIZE, buf)
end
if not tile.Visible then
tile.Visible = true
tile.Label.Visible = true
end
end
end
end
-- drop references so old vertex tables can be collected
for k = n + 1, bd.LastPrimCount do pr_a[k], pr_b[k], pr_c[k], pr_d[k], pr_t[k] = nil, nil, nil, nil, nil end
bd.LastPrimCount = n
end
---------------------------------------------------------
-- CORE LIFECYCLE
---------------------------------------------------------
--- @param parent Instance? # where the ScreenGui goes, defaults to the local player's PlayerGui
function ImGui_ImplRoblox_Init(parent)
local io = ImGui.GetIO()
local gui = Instance.new("ScreenGui")
gui.Name = "ImGui"
gui.IgnoreGuiInset = true -- so GetMouseLocation() and the tiles share the same origin
gui.ResetOnSpawn = false
gui.DisplayOrder = 1000
gui.Parent = parent or Players.LocalPlayer:WaitForChild("PlayerGui")
local bd = {
Time = os.clock(), Gui = gui, Connections = {},
Textures = {}, TextureCount = 0, MouseX = -1, MouseY = -1,
Tiles = {}, TileCols = 0, TileRows = 0, TH1 = {}, TH2 = {}, TN = {}, TL = {}, LastPrimCount = 0, ForceRedraw = true,
}
io.BackendPlatformUserData = bd
io.BackendFlags = bit32.bor(io.BackendFlags, ImGuiBackendFlags.RendererHasTextures, ImGuiBackendFlags.RendererHasVtxOffset)
local platform_io = ImGui.GetPlatformIO()
platform_io.Platform_SetClipboardTextFn = ImGui_ImplRoblox_PlatformSetClipboardText
platform_io.Platform_GetClipboardTextFn = ImGui_ImplRoblox_PlatformGetClipboardText
local screen = gui.AbsoluteSize
ImGui_ImplRoblox_UpdateMonitors(screen.X, screen.Y)
local function connect(signal, fn) table.insert(bd.Connections, signal:Connect(fn)) end
connect(UserInputService.InputBegan, function(input, game_processed)
local io = ImGui.GetIO()
local button = MOUSE_BUTTONS[input.UserInputType]
if button then
io:AddMouseSourceEvent(ImGuiMouseSource.Mouse)
io:AddMouseButtonEvent(button, true)
elseif input.UserInputType == Enum.UserInputType.Keyboard and not game_processed then
local ctrl, shift, alt = ImGui_ImplRoblox_UpdateKeyModifiers()
local key = KEY_MAP[input.KeyCode]
if key then io:AddKeyEvent(key, true) end
-- Text: printable ASCII keys, skipped while Ctrl/Alt are held (shortcuts)
local v = input.KeyCode.Value
if v >= 32 and v < 127 and not (ctrl or alt) then
local c = string.char(v)
if shift then c = SHIFTED[c] or c:upper() end
io:AddInputCharacter(string.byte(c))
end
end
end)
connect(UserInputService.InputEnded, function(input, game_processed)
local io = ImGui.GetIO()
local button = MOUSE_BUTTONS[input.UserInputType]
if button then
io:AddMouseButtonEvent(button, false)
elseif input.UserInputType == Enum.UserInputType.Keyboard then
ImGui_ImplRoblox_UpdateKeyModifiers()
local key = KEY_MAP[input.KeyCode]
if key then io:AddKeyEvent(key, false) end
end
end)
connect(UserInputService.InputChanged, function(input, game_processed)
if input.UserInputType == Enum.UserInputType.MouseWheel then
ImGui.GetIO():AddMouseWheelEvent(0, input.Position.Z)
end
end)
connect(UserInputService.WindowFocused, function() ImGui.GetIO():AddFocusEvent(true) end)
connect(UserInputService.WindowFocusReleased, function() ImGui.GetIO():AddFocusEvent(false) end)
end
function ImGui_ImplRoblox_Shutdown()
local io = ImGui.GetIO()
local bd = ImGui_ImplRoblox_GetBackendData()
for _, c in ipairs(bd.Connections) do c:Disconnect() end
DestroyTiles(bd)
bd.Gui:Destroy()
io.BackendPlatformUserData = nil
io.BackendFlags = bit32.band(io.BackendFlags, bit32.bnot(bit32.bor(
ImGuiBackendFlags.RendererHasTextures,
ImGuiBackendFlags.RendererHasVtxOffset
)))
end
function ImGui_ImplRoblox_NewFrame()
local io = ImGui.GetIO()
local bd = ImGui_ImplRoblox_GetBackendData()
local screen = bd.Gui.AbsoluteSize
local w, h = floor(screen.X), floor(screen.Y)
if w ~= bd.ScreenW or h ~= bd.ScreenH then
bd.ScreenW, bd.ScreenH = w, h
ImGui_ImplRoblox_UpdateMonitors(w, h)
end
ImVec2_CopyV(io.DisplaySize, w, h)
local current_time = os.clock()
io.DeltaTime = (current_time > bd.Time) and (current_time - bd.Time) or (1.0 / 60.0)
bd.Time = current_time
local m = UserInputService:GetMouseLocation()
if m.X ~= bd.MouseX or m.Y ~= bd.MouseY then
bd.MouseX, bd.MouseY = m.X, m.Y
io:AddMouseSourceEvent(ImGuiMouseSource.Mouse)
io:AddMousePosEvent(m.X, m.Y)
end
end
ImGui_ImplRoblox = {
Init = ImGui_ImplRoblox_Init,
Shutdown = ImGui_ImplRoblox_Shutdown,
NewFrame = ImGui_ImplRoblox_NewFrame,
RenderDrawData = ImGui_ImplRoblox_RenderDrawData,
AddFile = ImGui_ImplRoblox_AddFile,
}
return true -- [Roblox] ModuleScripts must return exactly one value