Effects¶

#include "chili/fx.hpp"

Particles, score popups, screen shake and drawing helpers. Everything is in chili::fx and draws to blit::screen.

A caught chilli: particles and a +10 popup

Particles¶

A fixed pool of pixel particles that fly out, fall and fade.

chili::fx::Particles particles;      // 48 particles

void on_eat(Point at) {
  particles.burst(at, Pen(235, 60, 70), 10);
}

void update(uint32_t time) {
  particles.update(10);
}

void render(uint32_t time) {
  draw_board();
  particles.render(shake.offset());
}

Member	Does
`Particles(size_t capacity = 48)`	The pool. Set once; nothing is allocated after this.
`burst(Point at, Pen color, int count, const Burst &how = {})`	Throws up to `count` particles. When the pool is full, the extra ones are dropped.
`update(uint32_t dt)`	Moves them.
`render(Point offset = {0, 0})`	Draws them, moved by `offset`.
`clear()`	Removes them all, for example when a round starts.
`active()`	How many are alive.
`gravity`	px per ms². Default 0.00015.

Tune a burst with Burst:

Field	Default	Means
`speed_min`, `speed_max`	0.02, 0.07	Speed in px per ms.
`lift`	0.03	Extra upward speed.
`life_min`, `life_max`	300, 600	Life in ms.
`sparkle`	`Pen(255, 255, 220)`	Half the particles take this colour. Alpha 0 turns it off.

chili::fx::Burst big;
big.speed_max = 0.12f;
big.life_max = 900;
particles.burst(at, gold, 40, big);

Floating text¶

Short texts that rise and fade: "+100", "COMBO!".

chili::fx::FloatingText popups;      // 6 at once

popups.add(at - Point(0, 6), "+100", gold);
popups.update(dt);
popups.render(shake.offset());

Member	Does
`FloatingText(size_t slots = 6)`	How many show at once. When all are busy, the oldest is replaced.
`add(Point at, std::string_view s, Pen color)`	Shows up to 11 characters centred on `at`.
`update(dt)`, `render(offset)`, `clear()`, `active()`	Like `Particles`.
`life_ms`, `rise`, `fade_ms`	700 ms, 0.02 px per ms, fades over the last 300 ms.

Keep popups on screen by clamping at yourself, for example at.x = std::clamp(at.x, 14, 114).

Shake¶

A random offset that calms down. Add it to whatever should shake.

chili::fx::Shake shake;

void on_hit() { shake.start(450); }

void update(uint32_t time) { shake.update(10); }

void render(uint32_t time) {
  Point o = shake.offset();
  draw_board(o);
  draw_hud();          // the HUD stays still
}

Member	Does
`start(uint32_t duration_ms, uint32_t ms_per_px = 120)`	Shakes up to `remaining / ms_per_px + 1` pixels: 4 px at the start of a 450 ms shake, 1 px at the end.
`update(dt)`	Counts down.
`offset()`	A new random offset each call; (0, 0) when done.
`active()`, `stop()`

Drawing helpers¶

Function	Draws
`text(s, Point p, Pen color, TextAlign align = top_left, bool shadow = true, const Font &font = minimal_font)`	Text with a 1 px drop shadow.
`big_text(s, Point center, int scale, Pen color, Pen shadow = Pen(0, 0, 0, 220))`	One line scaled up 2x, 3x..., centred, with a shadow.
`panel(Rect r)` / `panel(Rect r, Pen fill, Pen border)`	A box with a border and cut corners. Theme colours by default.
`dim(uint8_t alpha, Pen color = black)`	Covers the screen. Use it behind a pause menu or to fade.

fx::dim(140);                                       // darken the game
fx::panel(Rect(24, 36, 80, 58));                    // box for the menu
fx::big_text("PAUSED", Point(64, 47), 2, white);    // title
fx::text("A: OK", Point(64, 96), grey, TextAlign::top_center);

big_text scales minimal_font, so it stays crisp on the 128x128 screen.