Gameplay

Witches

Before the game starts, the player can choose two witches between the 8 available. The first one is used on normal mode, the second on focused mode. Each witch has unique properties and sometimes a special effect.

Modes

There are two gameplay modes:

1. Normal
2. Focused

The "focus" mode is triggered by pressing KEY_OPTN. The effect disapears when the key is released. Focus mode with speed divided by two, some bullets are ineffective, and usually a fire power focused on a single stream. They may have a special effect

Speeds are in px/s (play area is 270×224).

Id	Name	Spe	Pow	Special
0	Reimu Hakurei	194	130	+10% power when focused
1	Marisa Kirisame	208	130	Attract bonus when on top of the screen
2	Sariel	241		Do not attract bullets when not focused
3	Koakuma			+15% chance of getting a powerup
4	Iku Nagae			Start with 4 spells instead of 3
5	Sumireko Usami			Wider fire angle when not focused
6	Hina Kagiyama			+10% power when not focused
7	Kurumi

Power & fire

Power can go from 1 to

A bullet_t is always launched by the player. Else it's an enemy_t (even if it's an enemy bullet)

Powerups

There are 2 kinds of powerups: small ones and big ones. Small ones increase power by 1, big ones by 5.

Code architecture

Global vars

• uint32_t us_elapsed: μs elapsed during the last frame
• uint32_t frame: number of frames elapsed since the beginning of the game
• player_t *player: general information about player
• difficulty_t difficulty: the chosen difficulty of the game
• bullet_t *bullets: the bullets sent by player

Objects

object_t is an object linked to physic or an updater. This means that an enemy as well as a bullet can be objects.

Object updater

An object updater is a function applied to an object. Its protoype must follow this: void f(object_t*). Due to the complexity of the game, it may use frame, us_elapsed; but it could also use player, difficulty or other global variables.

Graphics

Graphics are designed for color calcs. However, I try to be the most responsible possible to facilitate a port to monochrome calcs. Thus, code may be quite verbose when displaying sprites.