311 lines
11 KiB
C
311 lines
11 KiB
C
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/*
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* Created by Brett on 30/03/23.
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* Licensed under GNU General Public License V3.0
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* See LICENSE file for license detail
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*/
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#ifndef ASSIGN3_PARTICLE_SYSTEM_H
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#define ASSIGN3_PARTICLE_SYSTEM_H
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#include <texture.h>
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#include <unordered_map>
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#include <blt/std/random.h>
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#include <vector>
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#include <queue>
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#include <algorithm>
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#include <util.h>
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#include <sstream>
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#include <config.h>
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struct particle_t {
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vec pos, dir;
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float speed;
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float age;
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};
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class particle_system {
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private:
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std::unordered_map<unsigned int, std::vector<particle_t*>> particles;
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blt::vec3 position;
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blt::vec3 direction;
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float spread;
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int pps;
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// current number of particles spawned in the last second
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int current_pps = 0;
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// delta to keep track of pps relative to the framerate
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double delta = 0;
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enum status_t {
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CONTINUOUS = 0, MANUAL = 1, SINGLE = 2
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};
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enum spray_status_t {
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DEFAULT = 0, LOW = 1, HIGH = 2
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};
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status_t status = CONTINUOUS;
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spray_status_t sprayMode = DEFAULT;
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const float sprays[3] = {1, 5, 10};
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bool applyFriction = true;
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bool randomizeTexture = false;
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blt::random<float> DIRECTION_RANDOMIZER{-1, 1};
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blt::random<float> TEXTURE_RANDOMIZER{0, 9};
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void spawnParticle() {
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auto* p = new particle_t;
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constexpr float SPEED_FACTOR = 25;
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unsigned int textureID = 0;
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if (randomizeTexture)
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textureID = (int) round(TEXTURE_RANDOMIZER.get());
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p->pos = conv(position);
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auto offset = blt::vec3{DIRECTION_RANDOMIZER.get(), 0, DIRECTION_RANDOMIZER.get()};
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p->dir = conv(direction * SPEED_FACTOR + offset.normalize() * spread * sprays[sprayMode]);
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p->speed = 1.0;
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p->age = 0;
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particles[textureID].push_back(p);
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}
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inline static double distance(const particle_t* p, const blt::vec3& pos){
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const auto ppos = p->pos;
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auto dx = ppos.x - pos.x();
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auto dy = ppos.y - pos.y();
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auto dz = ppos.z - pos.z();
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return dx * dx + dy * dy + dz * dz;
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}
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// vbo stuff
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// if I had access to GL3.3+ I could instance the particles which would be much faster to render
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// it wouldn't be hard as BLT has most of the math functions required and I could steal the
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// shader loader / VAO object implementation from my final project but that's a TODO:
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// the hard part is glut's apparent lack of gl3+ support
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// -- apparently needed glad for this, maybe it is possible without switching to glfw
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unsigned int quad = 0;
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const float s = 0.5;
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const float PARTICLE_LIFETIME = 25;
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public:
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particle_system(
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const blt::vec3& position, const blt::vec3& direction, float spread, int pps
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): position(position), direction(direction), spread(spread), pps(pps) {
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quad = glGenLists(1);
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glNewList(quad, GL_COMPILE);
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glBegin(GL_QUADS);
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glTexCoord2f(1, 0);
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glVertex3f(-s, s, 0);
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glTexCoord2f(1, 1);
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glVertex3f(-s, -s, 0);
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glTexCoord2f(0, 1);
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glVertex3f(s, -s, 0);
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glTexCoord2f(0, 0);
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glVertex3f(s, s, 0);
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glEnd();
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glEndList();
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}
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void update(camera& cam, float bnx, float bnz, float bpx, float bpz) {
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// used to keep updates correct without being dependent on FPS
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auto frameDeltaSeconds = ((double) getDelta() / 1000000000.0);
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const auto gravity_vec = vec{0, -GRAVITY, 0};
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for (auto& pair : particles) {
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std::queue<particle_t*> deleteList;
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for (auto& particle : pair.second) {
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auto ppos = particle->pos;
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particle->pos = ppos + particle->dir * particle->speed * frameDeltaSeconds;
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particle->age += (float) frameDeltaSeconds;
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float BOUNCE_FACTOR = 0.75;
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// bounce particle
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if (particle->pos.y < 0 && particle->pos.x > bnx && particle->pos.x < bpx &&
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particle->pos.z > bnz && particle->pos.z < bpz) {
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// NOTE: I am not deleting stationary particles because I think they look cool sitting on the floor.
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if (!applyFriction)
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BOUNCE_FACTOR = 1.0;
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particle->dir.y = -particle->dir.y * BOUNCE_FACTOR;
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particle->pos = ppos;
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}
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// remove particles outside the bounds of the world
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if (particle->pos.y < -50 || particle->age > PARTICLE_LIFETIME) {
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deleteList.push(particle);
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continue;
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}
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particle->dir = particle->dir + gravity_vec * frameDeltaSeconds;
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}
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while (!deleteList.empty()) {
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auto*& particle = deleteList.front();
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auto itr = std::find(pair.second.begin(), pair.second.end(), particle);
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if (itr != pair.second.end())
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pair.second.erase(itr);
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delete (particle);
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deleteList.pop();
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}
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}
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int particlesToSpawn = (int) (round(pps * frameDeltaSeconds));
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if (current_pps + particlesToSpawn > pps)
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particlesToSpawn = pps - current_pps;
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if (status == CONTINUOUS) {
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for (int i = 0; i < particlesToSpawn; i++)
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spawnParticle();
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} else if (status == MANUAL) {
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if (cam.isKeyPressed('f'))
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for (int i = 0; i < particlesToSpawn; i++)
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spawnParticle();
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}
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delta += frameDeltaSeconds;
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if (delta > 1.0) {
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current_pps = 0;
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delta = 0;
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}
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}
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inline static void applyBillboard() {
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GLfloat m[16];
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glMatrixMode(GL_MODELVIEW);
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glGetFloatv(GL_MODELVIEW_MATRIX, m);
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// undo all rotations (and scaling!) by setting rotation part to the identity matrix
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for (int i = 0; i < 3; i++) {
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for (int j = 0; j < 3; j++) {
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if (i == j)
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m[i * 4 + j] = 1.0;
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else
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m[i * 4 + j] = 0.0;
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}
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}
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glLoadMatrixf(m);
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}
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void render(camera& cam, texture** textures) {
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glMatrixMode(GL_MODELVIEW);
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// by batching particles by texture we save a little driver overhead
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for (auto& pair : particles) {
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//glBindTexture(GL_TEXTURE_2D, );
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textures[pair.first]->bind();
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auto& particles_vec = pair.second;
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// since we have enabled transparency, we need to sort the particles based on the distance to the camera.
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// TODO: this does not account for bill-boarding / rotation!
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// TODO: std::sort is likely a quick-sort derivative, insertion sort would be better as particles are always* mostly* sorted!
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std::sort(particles_vec.begin(), particles_vec.end(), [&](const particle_t* p1, const particle_t* p2) {
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auto d1 = distance(p1, cam.getPosition());
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auto d2 = distance(p2, cam.getPosition());
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return d1 > d2;
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});
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for (auto& p : particles_vec) {
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glPushMatrix();
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glTranslatef(p->pos.x, p->pos.y, p->pos.z);
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// due to the inefficiency of getting the modelview and updating it to billboard,
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// this will cause a considerable slow down.
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applyBillboard();
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glCallList(quad);
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glPopMatrix();
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}
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}
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auto err = glGetError();
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if (err != 0)
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std::cout << "GL Error: " << err << "\n";
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{
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std::stringstream str;
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str << WINDOW_TITLE;
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str << " | Particles: ";
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size_t count = 0;
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for (const auto& pair : particles)
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count += pair.second.size();
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str << count;
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str << " FPS: ";
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str << 1000000000.0 / (double)getDelta();
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str << " | Status: ";
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str << (status == CONTINUOUS ? "Continuous" : status == MANUAL ? "Manual" : "Single");
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str << " | Friction: ";
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str << (applyFriction ? "True" : "False");
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str << " | Spray: ";
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str << (sprayMode == DEFAULT ? "Default" : sprayMode == LOW ? "Low" : "High");
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str << " | Randomize: ";
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str << (randomizeTexture ? "True" : "False");
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glutSetWindowTitle(str.str().c_str());
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}
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}
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void randomizeSpeed(float n) {
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blt::random<float> SPEED_RANDOMIZER{1, n};
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for (auto& pair : particles)
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for (auto& p : pair.second)
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p->speed = SPEED_RANDOMIZER.get();
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}
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void setFriction(bool f){
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applyFriction = f;
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}
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[[nodiscard]] bool getFriction() const {
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return applyFriction;
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}
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void toggleSpray(){
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int currentSpray = sprayMode;
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// increment and bound the spray pattern
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currentSpray++;
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if (currentSpray > 2)
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currentSpray = 0;
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sprayMode = static_cast<spray_status_t>(currentSpray);
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}
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void toggleTexRandomizer() {
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randomizeTexture = !randomizeTexture;
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}
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void changeFiringMode(int mode){
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// wrap
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if (mode < 0)
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mode = SINGLE;
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if (mode > 2)
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mode = CONTINUOUS;
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// convert
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status = static_cast<status_t>(mode);
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}
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int getFiringMode(){
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return status;
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}
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void singleFire(){
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BLT_TRACE("Hello!");
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if (status == SINGLE)
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spawnParticle();
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}
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void reset(){
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particles.clear();
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}
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~particle_system() {
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glDeleteLists(quad, 1);
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for (const auto& pair : particles) {
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for (auto& particle : pair.second)
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delete (particle);
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}
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}
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};
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#endif //ASSIGN3_PARTICLE_SYSTEM_H
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