breakhack/src/particle_engine.c

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#include <stdlib.h>
#include "particle_engine.h"
#include "linkedlist.h"
#include "util.h"
#include "defines.h"
#include "vector2d.h"
typedef struct Particle_t {
Position pos;
Vector2d velocity;
Dimension dim;
unsigned int movetime;
unsigned int lifetime;
SDL_Color color;
} Particle;
typedef struct Engine_t {
LinkedList *particles;
} Engine;
static Engine *engine = NULL;
static void
check_engine(void)
{
if (!engine)
fatal("Particle engine not initiated");
}
void
particle_engine_init(void)
{
if (engine != NULL)
fatal("Engine already initiated");
engine = ec_malloc(sizeof(Engine));
engine->particles = linkedlist_create();
}
void
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particle_engine_bloodspray(Position pos, Dimension dim, unsigned int count)
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{
check_engine();
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if (count > 100)
count = 100;
for (unsigned int i = 0; i < count; ++i) {
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int x, y, xv, yv, w, h;
unsigned int mt, lt;
Particle *p;
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x = (rand() % dim.width) + pos.x;
y = (rand() % dim.height) + pos.y;
xv = (rand() % 200) - 100;
yv = (rand() % 200) - 100;
mt = (rand() % 10) + 10;
lt = (rand() % 120) + 60;
w = (rand() % 3) + 2;
h = (rand() % 3) + 2;
p = ec_malloc(sizeof(Particle));
p->pos = (Position) { x, y };
p->velocity = (Vector2d) { xv, yv };
p->movetime = mt;
p->lifetime = lt;
p->dim = (Dimension) { w, h };
p->color = (SDL_Color) { 255, 0, 0, 255 };
linkedlist_append(&engine->particles, p);
}
}
static void
move_particle(Particle *particle, float deltaTime)
{
if (!particle->movetime)
return;
particle->pos.x += particle->velocity.x * deltaTime;
particle->pos.y += particle->velocity.y * deltaTime;
}
void
particle_engine_update(float deltaTime)
{
check_engine();
LinkedList *current, *last;
current = engine->particles;
last = NULL;
while (current) {
Particle *particle = current->data;
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if (particle->movetime)
particle->movetime--;
if (particle->lifetime > 0) {
particle->lifetime--;
move_particle(current->data, deltaTime);
last = current;
current = current->next;
} else {
if (!last) {
engine->particles = current->next;
free(current->data);
free(current);
current = engine->particles;
} else {
last->next = current->next;
free(current->data);
free(current);
current = last->next;
}
}
}
}
static void
render_particle(Particle *p, Camera *cam)
{
Position pos = camera_to_camera_position(cam, &p->pos);
SDL_Rect box = { pos.x, pos.y, p->dim.width, p->dim.height };
SDL_SetRenderDrawColor(cam->renderer,
p->color.r,
p->color.b,
p->color.g,
p->color.a);
SDL_RenderFillRect(cam->renderer, &box);
}
void
particle_engine_render(Camera *cam)
{
check_engine();
LinkedList *particles = engine->particles;
while (particles) {
render_particle(particles->data, cam);
particles = particles->next;
}
}
void
particle_engine_clear(void)
{
check_engine();
while (engine->particles)
free(linkedlist_pop(&engine->particles));
}
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void
particle_engine_close(void)
{
check_engine();
while (engine->particles)
free(linkedlist_pop(&engine->particles));
free(engine);
engine = NULL;
}