add particles collision detection

src/graphics/render/Emitter.cpp

@@ -15,7 +15,8 @@ Emitter::Emitter(
       prototype(std::move(prototype)),
       texture(texture),
       spawnInterval(spawnInterval),
-      count(count) {
+      count(count),
+      behaviour() {
     this->prototype.emitter = this;
 }
 
@@ -37,6 +38,7 @@ void Emitter::update(float delta, std::vector<Particle>& particles) {
     while (count && timer > spawnInterval) {
         // spawn particle
         Particle particle = prototype;
+        particle.emitter = this;
         particle.position = position;
         particle.velocity += glm::ballRand(1.0f) * explosion;
         particles.push_back(std::move(particle));

src/graphics/render/Emitter.hpp

@@ -26,6 +26,11 @@ struct Particle {
 
 class Texture;
 
+struct ParticleBehaviour {
+    bool collision = true;
+    glm::vec3 gravity {0.0f, -16.0f, 0.0f};
+};
+
 class Emitter {
     /// @brief Static position or entity
     std::variant<glm::vec3, entityid_t> origin;
@@ -42,8 +47,10 @@ class Emitter {
     /// to spawn on update. May be innacurate.
     float timer = 0.0f;
     /// @brief Random velocity magnitude applying to spawned particles
-    glm::vec3 explosion {1.0f};
+    glm::vec3 explosion {8.0f};
 public:
+    ParticleBehaviour behaviour;
+
     Emitter(
         std::variant<glm::vec3, entityid_t> origin,
         Particle prototype,
@@ -52,6 +59,8 @@ public:
         int count
     );
 
+    explicit Emitter(const Emitter&) = delete;
+
     /// @return Emitter particles texture
     const Texture* getTexture() const;
 

src/graphics/render/ParticlesRenderer.cpp

@@ -6,22 +6,38 @@
 #include "graphics/core/Texture.hpp"
 #include "graphics/render/MainBatch.hpp"
 #include "window/Camera.hpp"
+#include "world/Level.hpp"
+#include "voxels/Chunks.hpp"
 
 size_t ParticlesRenderer::visibleParticles = 0;
 size_t ParticlesRenderer::aliveEmitters = 0;
 
-ParticlesRenderer::ParticlesRenderer(const Assets& assets)
-    : batch(std::make_unique<MainBatch>(1024)) {
+ParticlesRenderer::ParticlesRenderer(const Assets& assets, const Level& level)
+    : batch(std::make_unique<MainBatch>(1024)), level(level) {
 
-    auto region = util::get_texture_region(assets, "blocks:grass_side", "");
-    Emitter emitter(glm::vec3(0, 100, 0), Particle {
+    auto region = util::get_texture_region(assets, "blocks:bazalt", "");
+    emitters.push_back(std::make_unique<Emitter>(glm::vec3(0, 100, 0), Particle {
         nullptr, glm::vec3(), glm::vec3(), 5.0f, region.region
-    },region.texture, 0.001f, 1000);
-    emitters.push_back(std::make_unique<Emitter>(emitter));
+    },region.texture, 0.002f, -1));
 }
 
 ParticlesRenderer::~ParticlesRenderer() = default;
 
+static inline void update_particle(
+    Particle& particle, float delta, const Chunks& chunks
+) {
+    const auto& behave = particle.emitter->behaviour;
+    auto& pos = particle.position;
+    auto& vel = particle.velocity;
+
+    vel += delta * behave.gravity;
+    if (behave.collision && chunks.isObstacleAt(pos + vel * delta)) {
+        vel *= 0.0f;
+    }
+    pos += vel * delta;
+    particle.lifetime -= delta;
+}
+
 void ParticlesRenderer::renderParticles(const Camera& camera, float delta) {
     const auto& right = camera.right;
     const auto& up = camera.up;
@@ -41,7 +57,7 @@ void ParticlesRenderer::renderParticles(const Camera& camera, float delta) {
         while (iter != vec.end()) {
             auto& particle = *iter;
 
-            particle.position += particle.velocity * delta;
+            update_particle(particle, delta, *level.chunks);
 
             batch->quad(
                 particle.position,
@@ -52,8 +68,6 @@ void ParticlesRenderer::renderParticles(const Camera& camera, float delta) {
                 glm::vec3(1.0f),
                 particle.region
             );
-
-            particle.lifetime -= delta;
             if (particle.lifetime <= 0.0f) {
                 iter = vec.erase(iter);
             } else {

src/graphics/render/ParticlesRenderer.hpp

@@ -10,15 +10,17 @@ class Texture;
 class Assets;
 class Camera;
 class MainBatch;
+class Level;
 
 class ParticlesRenderer {
+    const Level& level;
     std::unordered_map<const Texture*, std::vector<Particle>> particles;
     std::vector<std::unique_ptr<Emitter>> emitters;
     std::unique_ptr<MainBatch> batch;
 
     void renderParticles(const Camera& camera, float delta);
 public:
-    ParticlesRenderer(const Assets& assets);
+    ParticlesRenderer(const Assets& assets, const Level& level);
     ~ParticlesRenderer();
 
     void render(const Camera& camera, float delta);

src/graphics/render/WorldRenderer.cpp

@@ -62,8 +62,9 @@ WorldRenderer::WorldRenderer(
           level->chunks.get(),
           &engine->getSettings()
       )),
-      particles(std::make_unique<ParticlesRenderer>(*engine->getAssets())) {
-
+      particles(std::make_unique<ParticlesRenderer>(
+          *engine->getAssets(), *frontend->getLevel()
+      )) {
     renderer = std::make_unique<ChunksRenderer>(
         level, frontend->getContentGfxCache(), &engine->getSettings()
     );