architecture

Architecture

Copyright (c) 2024-2026 Jack Waechter. MIT licensed.

AP2 (Application Primitives) is a few subsystems you turn on at AP_Init, then a set of headers you call from the game loop. There is no scene graph, no ECS, and no hidden renderer object.

Subsystems

AP_Init(AP_INIT_WINDOWING | AP_INIT_VIDEO | AP_INIT_AUDIO);
/* equivalent: AP_Init(AP_INIT_ALL); */

Flag	Owns
AP_INIT_WINDOWING	GLFW, window list, event pump
AP_INIT_VIDEO	Graphics device (OpenGL). Implies windowing.
AP_INIT_AUDIO	Mixer and output device. Independent of video.

AP_Quit() tears them down in reverse order. AP_PumpEvents() polls the OS and also ticks audio (one-shot reaping, ducking, muffling).

Frame shape

AP_PumpEvents()     input + audio update
AP_Tick()           wait for target FPS, returns dt (seconds)
AP_Clear()          begin the color buffer (and post capture, if enabled)
  2D / 3D / text    scene
  AP_Gui*           widgets (overlay by default)
AP_Present()        post stack, swap

There is one active window. After AP_CreateWindow, draw and input calls target that window.

Modules

<AP2/AP2.h> is an umbrella. Define exclude flags before the include:

#define AP2_NO_3D
#define AP2_NO_AUDIO
#include <AP2/AP2.h>

Flag	Drops
AP2_ONLY_CORE	Everything but types, error, logger, init
AP2_NO_GRAPHICS	Device, video, renderer, OpenGL, 3D
AP2_NO_<MODULE>	One header family (AUDIO, GUI, POST, …)

After include, AP2_HAS_AUDIO (and friends) is 0 or 1.

AP2_Internal.h is for src/core only.

Handles

Textures, images, sounds, shaders, fonts, tilesets, tilemaps, and windows are opaque pointers. Destroy what you create. Voices from AP_PlayOneShot are reaped automatically.

Backends

Concern	Implementation
Window / input	GLFW 3.5
GPU	OpenGL 4.6 via GLAD (3.3 core is the documented floor on some platforms)
Images / TTF	stb
Audio	miniaudio (WASAPI, CoreAudio, ALSA, …)

Application code never includes GLFW or GLAD unless you opt in with AP2_INCLUDE_OPENGL.

Identity

AP2_NAME          /* "AP2" */
AP2_FULL_NAME     /* "Application Primitives" */
AP2_DESCRIPTION
AP2_AUTHOR        /* "Jack Waechter" */
AP2_LICENSE       /* "MIT" */

Next

API overview lists each public header.