Find5

A 2D spot-the-difference game targeting everything from Windows 98 (Pentium 4, SDL 1.2, fixed-function OpenGL) through modern Linux and Windows.

The shared engine — audio, scripting, 2D rendering, asset registry — lives in goph-R/SOOB-Core and is also consumed by goph-R/SOOB-Engine (the 3D FPS). Find5 itself is just main.cpp + Lua scripts + assets.

Depends on SOOB-Core

Clone the shared engine next to this repo before building:

Win98/
├── Find5/         ← this repo
├── SOOB-Core/     ← clone alongside
└── SOOB-Engine/   ← optional, shares the same engine

git clone git@github.com:goph-R/SOOB-Core.git

Build scripts add -I../SOOB-Core/ so #include "script.h" etc. resolve into the shared engine. Engine-side Lua modules (e.g. engine.scene) are copied next to the .exe at build time.

Building

See CLAUDE.md for the full build matrix and toolchain details.

Quick reference:

• Linux: make (needs libsdl1.2-dev, libopenal-dev) → find5
• Windows 98 / Dev-C++: build.bat → Find5.exe
• Windows 10 / portable MinGW: build_win10.bat → Find5_w10.exe
• CMake: mkdir build && cd build && cmake .. && make

Running

Run the executable from the repo root — assets are loaded by relative path.

The game: pick 5 differences between two portrait images per level, 10 levels per run, with a timer + jokers + per-category highscores. Click either image to mark a find; the joker button reveals the first unfound difference (yellow ellipse vs. green for player finds). Miss-click penalises ¼ of the remaining time. Pause / level-complete / game-over / all-done all open animated modal dialogs (drop-in with easeOutBounce, shoot-up exit with easeInExpo). Design notes: docs/game-plan.md, docs/menu-plan.md.

CLI flags: -w <width>, -h <height>, -fullscreen.

Input (Lua side)

Hooks (all optional, define in scripts/main.lua):

function on_update(dt) end
function on_keydown(name) end           -- "space", "left", "a", "f1" ...
function on_keyup(name) end
function on_mousedown(x, y, button) end -- 1=L, 2=M, 3=R, 4=wheel-up, 5=wheel-down
function on_mouseup(x, y, button) end
function on_mousemove(x, y, dx, dy) end

Polling (anywhere):

• key_down(name) -> bool
• mouse_pos() -> x, y
• mouse_down(button) -> bool

Mouse coords are in the virtual canvas (center origin, Y-down, ~540 units tall) — the same coord space uiIcon / uiText draw into.

Rendering from Lua

Draw calls go inside on_render(). The unit of drawing is a region — a named sub-rectangle of a texture, declared in assets.lua:

-- assets.lua
textures = { sprite = "assets/textures/logo.png" }
regions  = { logo   = { tex = "sprite", x = 0, y = 0, w = 256, h = 64 } }

-- scripts/main.lua
function on_render()
    draw_region("logo", player.x, player.y, ALIGN_CENTER + ALIGN_MIDDLE)
end

draw_region(name, x, y [, align [, flip [, fill_x [, fill_y]]]]):

• align — ALIGN_LEFT=1 | ALIGN_CENTER=2 | ALIGN_RIGHT=4 (horizontal) OR ALIGN_TOP=8 | ALIGN_MIDDLE=16 | ALIGN_BOTTOM=32 (vertical). Bit-OR them; default (0 or omitted) = TOP-LEFT.
• flip — FLIP_H=1 | FLIP_V=2. Default 0.
• fill_x, fill_y — fractions in [0,1], default 1.0. Less than 1 clips the region from the side opposite the anchor — perfect for progress bars:

-- HP bar at 60%, anchored at top-left of (50, 50), drains rightward:
draw_region("hpbar", 50, 50, ALIGN_LEFT + ALIGN_TOP, 0, hp / max_hp)

Drawn 1:1 (one source pixel = one virtual-canvas unit, where the canvas is 480 units tall — matching Find5's 4:3 / 640×480 design target — and width scales with aspect). Textures and regions are lazy-loaded and cached.

Other rendering bindings (all support an options-table for color/alpha/etc.):

draw_text("HELLO", x, y, { scale = 3, font = "orbitron",
                           align = ALIGN_CENTER + ALIGN_MIDDLE,
                           color = { 1, 1, 0 } })

-- "Drawing" animation: tween `finish` 0 → 1 over time and the arc fills in.
draw_ellipse(cx, cy, rx, ry, { finish = anim_t, thickness = 3,
                               color = { 1, 0.3, 0.3, 1 - fade_t } })

See docs/game-plan.md for the full design of the Find5 game built on this engine.

Customizing

• Add a sprite: drop a PNG in assets/textures/, register it in assets.lua under textures, then in main.cpp look it up via assetRegFindTexture(&assetReg, "name") and load with loadTextureExA. Draw it inside the uiBegin/uiEnd block with uiIcon.
• Add a sound: drop a 16-bit PCM WAV in assets/sounds/, register it in assets.lua under sounds, then call snd_play("name") from Lua or sndPlay(&snd, sndLibPick(&sndLib, "name")) from C.
• Add a music track: drop an OGG in assets/music/, register in assets.lua under music, then music_play("name") from Lua.

Credits and licensing

Code

Engine source (everything outside vendor/ and vendor_win10/) is MIT-licensed — see LICENSE. Bundled third-party libraries retain their own licenses:

Library	License	Usage
SDL 1.2	LGPL 2.1	dynamically linked (SDL.dll)
OpenAL Soft	LGPL 2.1	dynamically linked (OpenAL32.dll)
Lua 5.1.5	MIT	compiled from vendored source
stb_image, stb_vorbis	Public Domain / MIT	compiled from vendored source

Assets

All assets carried over from SDLFun are © Dynart, all rights reserved. Exceptions:

• assets/fonts/orbitron*.fnt + assets/fonts/orbitron*_0.png — BMFont bakes of Orbitron by Matt McInerney, licensed under the SIL Open Font License 1.1.