[>]quakepg-engine

quakepg was meant to become a first-person roguelike dungeon crawler with a medieval setting and a PS1 look, on an engine written from scratch. I laid it out after Jason Gregory's "Game Engine Architecture". It lasted two days of commits: you can walk around one dungeon and swing a sword at nothing.

##Layout

The engine is a static library (libquakepg_engine.a) and the game is a separate executable that links it. The code is C with structs: plain data plus prefixed free functions in namespace qp, like window_create, shader_bind and mesh_draw.

core       types, math, log, assert, console, debug UI
platform   window, input, timer (GLFW underneath)
renderer   shader, mesh, texture, material, camera, model
physics    AABB collision

The rule was that the game only talks to that API. In practice main.cpp still includes GLFW to start Dear ImGui.

##The PSX look

The game renders at 640x480 into a framebuffer and scales it up with nearest filtering. psx.vert and psx.frag do the rest:

• vertex snapping in clip space (off by default, the grid size is a slider)
• color depth cut to 31 levels per channel, with a 4x4 Bayer dither
• linear fog computed per vertex

Affine texture warping didn't survive. The corners of the dungeon quads distorted, subdividing them only half helped, and the last rendering commit switched to perspective-correct textures.

##The dungeon

The map is ASCII in game/src/main.cpp. # is a wall, . is floor and P is where you spawn:

################
#......P.......#
#..............#
#..####..####..#
#..#........#..#

dungeon_map_load turns it into floor, wall and ceiling meshes and a list of wall boxes. The player is an AABB that slides along those boxes, with gravity and a jump.

The sword is a GLB loaded through Assimp. It gets its own 70 degree projection so it doesn't poke through walls, bobs while you walk, and plays a swing on left click. Nothing checks what the swing hits.

Tab opens a Dear ImGui menu for resolution, FOV, movement, gravity, snapping, fog, dithering, color depth and the sword's transform. The backtick key opens a console that knows help and clear.

##What never happened

The README's next steps are still next steps: procedural maps instead of the hardcoded one, enemies, health and a HUD, audio, and a map editor.

##Build

Linux only as written. GLFW, glad and Dear ImGui are in vendor/. Assimp has to come from the system (libassimp-dev on Debian), which the README's package list leaves out.

sudo apt-get install build-essential cmake libx11-dev libxrandr-dev libxcursor-dev libxinerama-dev libxi-dev

mkdir -p build && cd build
cmake .. -DCMAKE_BUILD_TYPE=Debug
make -j$(nproc)

cd ..
./quakepg_game

The binary lands in the repo root and loads assets/ from the working directory, so run it from there. scripts/run.sh does the build and the run in one go.

WASD moves, the mouse looks, Shift sprints, Space jumps, left click swings, Esc quits.