#include "particle.h" #include "stb_ds.h" #include "render.h" #include "2dphysics.h" #include "math.h" #include "log.h" emitter *make_emitter() { emitter *e = calloc(sizeof(*e),1); e->max = 20; arrsetcap(e->particles, 10); for (int i = 0; i < arrlen(e->particles); i++) e->particles[i].life = 0; e->life = 10; e->tte = lerp(e->explosiveness, e->life/e->max, 0); e->scale = 1; e->speed = 20; e->buffer = sg_make_buffer(&(sg_buffer_desc){ .size = sizeof(struct par_vert), .type = SG_BUFFERTYPE_STORAGEBUFFER, .usage = SG_USAGE_STREAM }); return e; } void emitter_free(emitter *e) { arrfree(e->particles); arrfree(e->verts); free(e); } /* Variate a value around variance. Variance between 0 and 1. */ float variate(float val, float variance) { return val + val*(frand(variance)-(variance/2)); } int emitter_spawn(emitter *e, transform *t) { if (arrlen(e->particles) == e->max) return 0; particle p = {0}; p.life = e->life; p.pos = (HMM_Vec4){t->pos.x,t->pos.y,t->pos.z,0}; HMM_Vec3 up = transform_direction(t, vFWD); float newan = (frand(e->divergence)-(e->divergence/2))*HMM_TurnToRad; HMM_Vec2 v2n = HMM_V2Rotate((HMM_Vec2){0,1}, newan); HMM_Vec3 norm = (HMM_Vec3){v2n.x, v2n.y,0}; p.v = HMM_MulV4F((HMM_Vec4){norm.x,norm.y,norm.z,0}, variate(e->speed, e->variation)); p.angle = 0.25; p.scale = variate(e->scale*t->scale.x, e->scale_var); arrput(e->particles,p); return 1; } void emitter_emit(emitter *e, int count, transform *t) { for (int i = 0; i < count; i++) emitter_spawn(e, t); } void emitter_draw(emitter *e) { if (arrlen(e->particles) == 0) return; arrsetlen(e->verts, arrlen(e->particles)); for (int i = 0; i < arrlen(e->particles); i++) { if (e->particles[i].time >= e->particles[i].life) continue; particle *p = e->particles+i; e->verts[i].pos = p->pos.xy; e->verts[i].angle = p->angle; e->verts[i].scale = p->scale; /* if (p->time < e->grow_for) e->verts[i].scale = lerp(p->time/e->grow_for, 0, p->scale); else if (p->time > (p->life - e->shrink_for)) e->verts[i].scale = lerp((p->time-(p->life-e->shrink_for))/e->shrink_for, p->scale, 0);*/ e->verts[i].color = p->color; } sg_range verts; verts.ptr = e->verts; verts.size = sizeof(*e->verts)*arrlen(e->verts); if (sg_query_buffer_will_overflow(e->buffer, verts.size)) { sg_destroy_buffer(e->buffer); e->buffer = sg_make_buffer(&(sg_buffer_desc){ .size = verts.size, .type = SG_BUFFERTYPE_STORAGEBUFFER, .usage = SG_USAGE_STREAM }); } sg_append_buffer(e->buffer, &verts); } void emitter_step(emitter *e, double dt, transform *t) { HMM_Vec4 g_accel = HMM_MulV4F((HMM_Vec4){cpSpaceGetGravity(space).x, cpSpaceGetGravity(space).y, 0, 0}, dt); for (int i = 0; i < arrlen(e->particles); i++) { if (e->particles[i].time >= e->particles[i].life) continue; //if (e->warp_mask & gravmask) // e->particles[i].v = HMM_AddV4(e->particles[i].v, g_accel); e->particles[i].pos = HMM_AddV4(e->particles[i].pos, HMM_MulV4F(e->particles[i].v, dt)); e->particles[i].angle += e->particles[i].av*dt; e->particles[i].time += dt; e->particles[i].color = sample_sampler(&e->color, e->particles[i].time/e->particles[i].life); e->particles[i].scale = e->scale; if (e->particles[i].time >= e->particles[i].life) arrdelswap(e->particles, i); // else if (query_point(e->particles[i].pos.xy)) // arrdelswap(e->particles,i); } e->tte-=dt; float step = lerp(e->explosiveness, e->life/e->max,0); while (e->tte <= 0) { e->tte += step; if (!emitter_spawn(e, t)) break; } }