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/* SPDX-License-Identifier: MIT */
/*
* konparticles.h
*
* Copyright (c) 2026 KonAki
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#ifndef KONPARTICLES_H
#define KONPARTICLES_H
#include "konsofren.h"
#ifdef __cplusplus
extern "C" {
#endif
/*** definition ***/
typedef struct kon_particle {
float x, y, vx, vy;
float age, life; /* life is 0 for a free slot */
float size0, size1;
uint32_t color0, color1;
} kon_particle_t;
/* a stream of small things, sparks, dust, rain, snow, smoke. one of these is one kind of thing, use several for several kinds.
the particles live in a pool you give it, so nothing is allocated and a full pool just means no new ones are made.
kon_particlesInit gives plain white specks, fill in the public fields to change them. everything is in pixels and seconds, a particle at a whole x and y sits on the middle of that pixel */
typedef struct kon_particles {
kon_particle_t *pool;
int capacity;
/* where they are born: a random point in this rectangle */
float x, y, width, height;
float rate; /* born every second, 0 for only bursts */
/* how they leave: the direction in radians with 0 to the right and a quarter turn down, a random speed and lifetime */
float angle, spread; /* spread is how far either side of the angle */
float speedMin, speedMax;
float lifeMin, lifeMax;
float ax, ay; /* acceleration, gravity and wind */
kon_rect_t area; /* if it has a size, particles die when they leave it */
/* how they look over their life, blended from the first to the last. size is in pixels and never goes under 1, fade with alpha */
float size0, size1;
uint32_t color0, color1;
float stretch; /* 0 for squares, otherwise they are long in the way they move, this many seconds of movement long */
kon_blend_t blend;
const kon_image *image; /* NULL for squares, otherwise each is this picture (or the part of it in src) drawn size pixels wide */
kon_rect_t src;
/* private */
float carry;
uint32_t seed;
} kon_particles_t;
/* capacity is how many can be alive at once. seed any number, the same seed makes the same effect */
void kon_particlesInit(kon_particles_t *ps, kon_particle_t *pool, int capacity, uint32_t seed);
/* makes count at once, as many as there is room for. returns how many */
int kon_particlesBurst(kon_particles_t *ps, int count);
void kon_particlesUpdate(kon_particles_t *ps, float dt);
/* how many are alive */
int kon_particlesCount(const kon_particles_t *ps);
/* removes them all */
void kon_particlesClear(kon_particles_t *ps);
/* offset is added to every position, for a camera that scrolls */
void kon_particlesDraw(const kon_particles_t *ps, kon_framebuffer_t *fb, int offsetX, int offsetY);
/*** weather ***/
/* set the emitter up as rain, snow or a storm for a view of that size. power from 1 to 9 is how heavy, like RPG Maker's.
they only change the public fields, so adjust them afterwards. call kon_particlesUpdate and kon_particlesDraw as usual,
with a pool of a few hundred (power 9 on a large view wants more, particles that do not fit are skipped) */
void kon_weatherRain(kon_particles_t *ps, int viewWidth, int viewHeight, int power);
void kon_weatherSnow(kon_particles_t *ps, int viewWidth, int viewHeight, int power);
void kon_weatherStorm(kon_particles_t *ps, int viewWidth, int viewHeight, int power);
#ifdef __cplusplus
}
#endif
#endif
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