nuclear@0: #include <stdio.h>
nuclear@0: #include <stdlib.h>
nuclear@0: #include <vector>
nuclear@0: #include <algorithm>
nuclear@0: #include "opengl.h"
nuclear@0: #include "psys.h"
nuclear@0: 
nuclear@0: #define MAX_SPAWNMAP_SAMPLES	2048
nuclear@0: 
nuclear@0: static double frand();
nuclear@0: static float rndval(float x, float range);
nuclear@0: static Particle *palloc();
nuclear@0: static void pfree(Particle *p);
nuclear@0: static void pfreelist(Particle *p);
nuclear@0: 
nuclear@0: void psys_default(PSysParam *pp)
nuclear@0: {
nuclear@0: 	// default parameters
nuclear@0: 	pp->spawn_rate = 10.0;
nuclear@0: 	pp->spawn_range = 0.0;
nuclear@0: 	pp->life = 1.0;
nuclear@0: 	pp->life_range = 0.0;
nuclear@0: 	pp->size = 1.0;
nuclear@0: 	pp->size_range = 0.0;
nuclear@0: 	pp->spawn_map = 0;
nuclear@0: 	pp->spawn_map_speed = 0.0;
nuclear@0: 
nuclear@0: 	pp->gravity = Vector3(0, -9.2, 0);
nuclear@0: 
nuclear@0: 	pp->pimg = 0;
nuclear@0: 	pp->pcolor_start = pp->pcolor_mid = pp->pcolor_end = Vector3(1, 1, 1);
nuclear@0: 	pp->palpha_start = 1.0;
nuclear@0: 	pp->palpha_mid = 0.5;
nuclear@0: 	pp->palpha_end = 0.0;
nuclear@0: 	pp->pscale_start = pp->pscale_mid = pp->pscale_end = 1.0;
nuclear@0: }
nuclear@0: 
nuclear@0: ParticleSystem::ParticleSystem()
nuclear@0: {
nuclear@0: 	active = true;
nuclear@0: 	active_time = 0.0f;
nuclear@0: 	spawn_pending = 0.0f;
nuclear@0: 	plist = 0;
nuclear@0: 	pcount = 0;
nuclear@0: 	smcache = 0;
nuclear@0: 
nuclear@0: 	expl = false;
nuclear@0: 	expl_force = expl_dur = 0.0f;
nuclear@0: 	expl_life = 0.0f;
nuclear@0: 
nuclear@0: 	psys_default(&pp);
nuclear@0: }
nuclear@0: 
nuclear@0: ParticleSystem::~ParticleSystem()
nuclear@0: {
nuclear@0: 	pfreelist(plist);
nuclear@0: 	delete [] smcache;
nuclear@0: }
nuclear@0: 
nuclear@0: void ParticleSystem::explode(const Vector3 &c, float force, float dur, float life)
nuclear@0: {
nuclear@0: 	expl_dur = dur;
nuclear@0: 	expl_force = force;
nuclear@0: 	expl_cent = c;
nuclear@0: 	expl_life = life;
nuclear@0: 	expl = true;
nuclear@0: }
nuclear@0: 
nuclear@0: bool ParticleSystem::alive() const
nuclear@0: {
nuclear@0: 	return active || pcount > 0;
nuclear@0: }
nuclear@0: 
nuclear@0: void ParticleSystem::update(float dt)
nuclear@0: {
nuclear@0: 	if(pp.spawn_map && !smcache) {
nuclear@0: 		gen_spawnmap(MAX_SPAWNMAP_SAMPLES);
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	if(active) {
nuclear@0: 		active_time += dt;
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	if(expl) {
nuclear@0: 		expl = false;
nuclear@0: 		//active = false;
nuclear@0: 
nuclear@0: 		Vector3 cent = expl_cent + pos;
nuclear@0: 
nuclear@0: 		Particle *p = plist;
nuclear@0: 		while(p) {
nuclear@0: 			p->max_life = expl_dur;
nuclear@0: 			Vector3 dir = p->pos - cent;
nuclear@0: 			p->vel += (normalize(dir + Vector3((frand() - 0.5) * 0.5, frand() - 0.5, (frand() - 0.5) * 0.5))) * expl_force;
nuclear@0: 			p = p->next;
nuclear@0: 		}
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	if(expl_life > 0.0) {
nuclear@0: 		expl_life -= dt;
nuclear@0: 		if(expl_life <= 0.0) {
nuclear@0: 			expl_life = 0.0;
nuclear@0: 			active = false;
nuclear@0: 		}
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	// update active particles
nuclear@0: 	Particle *p = plist;
nuclear@0: 	while(p) {
nuclear@0: 		p->life += dt;
nuclear@0: 		if(p->life < p->max_life) {
nuclear@0: 			float t = p->life / p->max_life;
nuclear@0: 
nuclear@0: 			p->pos = p->pos + p->vel * dt;
nuclear@0: 			p->vel = p->vel + pp.gravity * dt;
nuclear@0: 
nuclear@0: 			if(t < 0.5) {
nuclear@0: 				t *= 2.0;
nuclear@0: 				p->color = lerp(pp.pcolor_start, pp.pcolor_mid, t);
nuclear@0: 				p->alpha = lerp(pp.palpha_start, pp.palpha_mid, t);
nuclear@0: 				p->scale = lerp(pp.pscale_start, pp.pscale_mid, t);
nuclear@0: 			} else {
nuclear@0: 				t = (t - 0.5) * 2.0;
nuclear@0: 				p->color = lerp(pp.pcolor_mid, pp.pcolor_end, t);
nuclear@0: 				p->alpha = lerp(pp.palpha_mid, pp.palpha_end, t);
nuclear@0: 				p->scale = lerp(pp.pscale_mid, pp.pscale_end, t);
nuclear@0: 			}
nuclear@0: 
nuclear@0: 		} else {
nuclear@0: 			p->life = -1.0;
nuclear@0: 		}
nuclear@0: 		p = p->next;
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	// remove dead particles
nuclear@0: 	Particle dummy;
nuclear@0: 	dummy.next = plist;
nuclear@0: 	p = &dummy;
nuclear@0: 	while(p->next) {
nuclear@0: 		if(p->next->life < 0.0) {
nuclear@0: 			Particle *tmp = p->next;
nuclear@0: 			p->next = tmp->next;
nuclear@0: 			pfree(tmp);
nuclear@0: 			--pcount;
nuclear@0: 		} else {
nuclear@0: 			p = p->next;
nuclear@0: 		}
nuclear@0: 	}
nuclear@0: 	plist = dummy.next;
nuclear@0: 
nuclear@0: 	float spawn_rate = pp.spawn_rate;
nuclear@0: 	if(pp.spawn_map && pp.spawn_map_speed > 0.0) {
nuclear@0: 		float s = active_time * pp.spawn_map_speed;
nuclear@0: 		if(s > 1.0) s = 1.0;
nuclear@0: 		spawn_rate *= s;
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	// spawn particles as needed
nuclear@0: 	if(active) {
nuclear@0: 		spawn_pending += spawn_rate * dt;
nuclear@0: 
nuclear@0: 		while(spawn_pending >= 1.0f) {
nuclear@0: 			spawn_pending -= 1.0f;
nuclear@0: 			spawn_particle();
nuclear@0: 		}
nuclear@0: 	}
nuclear@0: }
nuclear@0: 
nuclear@0: void ParticleSystem::draw() const
nuclear@0: {
nuclear@0: 	int cur_sdr = 0;
nuclear@0: 	glGetIntegerv(GL_CURRENT_PROGRAM, &cur_sdr);
nuclear@0: 	if(cur_sdr) {
nuclear@0: 		glUseProgram(0);
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	glPushAttrib(GL_ENABLE_BIT | GL_COLOR_BUFFER_BIT);
nuclear@0: 	glDisable(GL_LIGHTING);
nuclear@0: 	glEnable(GL_BLEND);
nuclear@0: 	glBlendFunc(GL_SRC_ALPHA, GL_ONE);
nuclear@0: 
nuclear@0: 	if(pp.pimg) {
nuclear@0: 		if(!pp.pimg->texture) {
nuclear@0: 			pp.pimg->gen_texture();
nuclear@0: 		}
nuclear@0: 		glEnable(GL_TEXTURE_2D);
nuclear@0: 		glBindTexture(GL_TEXTURE_2D, pp.pimg->texture);
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	glBegin(GL_QUADS);
nuclear@0: 	Particle *p = plist;
nuclear@0: 	while(p) {
nuclear@0: 		float hsz = p->size * p->scale * 0.5;
nuclear@0: 		glColor4f(p->color.x, p->color.y, p->color.z, p->alpha);
nuclear@0: 		glTexCoord2f(0, 0); glVertex3f(p->pos.x - hsz, p->pos.y - hsz, p->pos.z);
nuclear@0: 		glTexCoord2f(1, 0); glVertex3f(p->pos.x + hsz, p->pos.y - hsz, p->pos.z);
nuclear@0: 		glTexCoord2f(1, 1); glVertex3f(p->pos.x + hsz, p->pos.y + hsz, p->pos.z);
nuclear@0: 		glTexCoord2f(0, 1); glVertex3f(p->pos.x - hsz, p->pos.y + hsz, p->pos.z);
nuclear@0: 		p = p->next;
nuclear@0: 	}
nuclear@0: 	glEnd();
nuclear@0: 
nuclear@0: 	glPopAttrib();
nuclear@0: 
nuclear@0: 	if(cur_sdr) {
nuclear@0: 		glUseProgram(cur_sdr);
nuclear@0: 	}
nuclear@0: }
nuclear@0: 
nuclear@0: void ParticleSystem::gen_spawnmap(int count)
nuclear@0: {
nuclear@0: 	Image *img = pp.spawn_map;
nuclear@0: 	if(!img) return;
nuclear@0: 
nuclear@0: 	delete [] smcache;
nuclear@0: 	smcache = new Vector3[count];
nuclear@0: 
nuclear@0: 	float umax = (float)img->width;
nuclear@0: 	float vmax = (float)img->height;
nuclear@0: 	float aspect = umax / vmax;
nuclear@0: 
nuclear@0: 	// first generate a bunch of random samples by rejection sampling
nuclear@0: 	printf("generating %d random spawnmap samples\n", count);
nuclear@0: 	for(int i=0; i<count; i++) {
nuclear@0: 		float u, v;
nuclear@0: 		unsigned char val, ord;
nuclear@0: 
nuclear@0: 		do {
nuclear@0: 			u = (double)rand() / (double)RAND_MAX;
nuclear@0: 			v = (double)rand() / (double)RAND_MAX;
nuclear@0: 
nuclear@0: 			int x = (int)(u * umax);
nuclear@0: 			int y = (int)(v * vmax);
nuclear@0: 
nuclear@0: 			unsigned char *pptr = img->pixels + (y * img->width + x) * 3;
nuclear@0: 			val = pptr[0];
nuclear@0: 			ord = pptr[1];
nuclear@0: 		} while(val < 192);
nuclear@0: 
nuclear@0: 		smcache[i] = Vector3(u * 2.0 - 1.0, (1.0 - v * 2.0) / aspect, ord / 255.0);
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	// then order by z
nuclear@0: 	std::sort(smcache, smcache + count,
nuclear@0: 			[](const Vector3 &a, const Vector3 &b) { return a.z < b.z; });
nuclear@0: 
nuclear@0: 	// precalculate the bounds of each slot
nuclear@0: 	smcache_max[0] = 0;
nuclear@0: 	for(int i=1; i<255; i++) {
nuclear@0: 		float maxval = (float)i / 255.0;
nuclear@0: 
nuclear@0: 		int idx = smcache_max[i - 1];
nuclear@0: 		while(++idx < count && smcache[idx].z < maxval);
nuclear@0: 		smcache_max[i] = idx;
nuclear@0: 	}
nuclear@0: 	smcache_max[255] = count;
nuclear@0: }
nuclear@0: 
nuclear@0: static double frand()
nuclear@0: {
nuclear@0: 	return (double)rand() / (double)RAND_MAX;
nuclear@0: }
nuclear@0: 
nuclear@0: static float rndval(float x, float range)
nuclear@0: {
nuclear@0: 	if(fabs(range) < 1e-6) {
nuclear@0: 		return x;
nuclear@0: 	}
nuclear@0: 	return x + (frand() * range - range * 0.5);
nuclear@0: }
nuclear@0: 
nuclear@0: void ParticleSystem::spawn_particle()
nuclear@0: {
nuclear@0: 	Particle *p = palloc();
nuclear@0: 	p->pos = Vector3(rndval(pos.x, pp.spawn_range),
nuclear@0: 			rndval(pos.y, pp.spawn_range),
nuclear@0: 			rndval(pos.z, pp.spawn_range));
nuclear@0: 	p->vel = Vector3(0, 0, 0);
nuclear@0: 	p->color = pp.pcolor_start;
nuclear@0: 	p->alpha = pp.palpha_start;
nuclear@0: 	p->life = 0.0;
nuclear@0: 	p->max_life = rndval(pp.life, pp.life_range);
nuclear@0: 	p->size = rndval(pp.size, pp.size_range);
nuclear@0: 	p->scale = pp.pscale_start;
nuclear@0: 
nuclear@0: 	if(pp.spawn_map) {
nuclear@0: 		float maxz = pp.spawn_map_speed > 0.0 ? active_time * pp.spawn_map_speed : 1.0;
nuclear@0: 		int max_idx = (int)(maxz * 255.0);
nuclear@0: 		if(max_idx > 255) max_idx = 255;
nuclear@0: 		if(max_idx < 1) max_idx = 1;
nuclear@0: 
nuclear@0: 		int idx = rand() % smcache_max[max_idx];
nuclear@0: 
nuclear@0: 		p->pos.x += smcache[idx].x;
nuclear@0: 		p->pos.y += smcache[idx].y;
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	p->next = plist;
nuclear@0: 	plist = p;
nuclear@0: 	++pcount;
nuclear@0: }
nuclear@0: 
nuclear@0: // particle allocator
nuclear@0: #define MAX_POOL_SIZE	8192
nuclear@0: static Particle *ppool;
nuclear@0: static int ppool_size;
nuclear@0: 
nuclear@0: static Particle *palloc()
nuclear@0: {
nuclear@0: 	if(ppool) {
nuclear@0: 		Particle *p = ppool;
nuclear@0: 		ppool = ppool->next;
nuclear@0: 		--ppool_size;
nuclear@0: 		return p;
nuclear@0: 	}
nuclear@0: 	return new Particle;
nuclear@0: }
nuclear@0: 
nuclear@0: static void pfree(Particle *p)
nuclear@0: {
nuclear@0: 	if(!p) return;
nuclear@0: 
nuclear@0: 	if(ppool_size < MAX_POOL_SIZE) {
nuclear@0: 		p->next = ppool;
nuclear@0: 		ppool = p;
nuclear@0: 		++ppool_size;
nuclear@0: 	} else {
nuclear@0: 		delete p;
nuclear@0: 	}
nuclear@0: }
nuclear@0: 
nuclear@0: static void pfreelist(Particle *p)
nuclear@0: {
nuclear@0: 	if(!p) return;
nuclear@0: 
nuclear@0: 	Particle *it = p;
nuclear@0: 	int new_pool_size = ppool_size;
nuclear@0: 
nuclear@0: 	while(it->next && new_pool_size < MAX_POOL_SIZE) {
nuclear@0: 		it = it->next;
nuclear@0: 		++new_pool_size;
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	Particle *last = it;
nuclear@0: 	it = it->next;
nuclear@0: 
nuclear@0: 	// add the first lot to the pool
nuclear@0: 	last->next = ppool;
nuclear@0: 	ppool = p;
nuclear@0: 	ppool_size = new_pool_size;
nuclear@0: 
nuclear@0: 	// delete the rest;
nuclear@0: 	while(it) {
nuclear@0: 		p = it;
nuclear@0: 		it = it->next;
nuclear@0: 		delete p;
nuclear@0: 	}
nuclear@0: }