add 'size_spread' particles parameter

src/graphics/render/ParticlesRenderer.cpp

@@ -89,11 +89,13 @@ void ParticlesRenderer::renderParticles(const Camera& camera, float delta) {
                 );
                 light *= 0.9f + (particle.random % 100) * 0.001f;
             }
+            float scale = 1.0f + ((particle.random ^ 2628172) % 1000) *
+                                     0.001f * preset.sizeSpread;
             batch->quad(
                 particle.position,
                 right,
                 preset.globalUpVector ? glm::vec3(0, 1, 0) : up,
-                preset.size,
+                preset.size * scale,
                 light,
                 glm::vec3(1.0f),
                 particle.region

src/presets/ParticlesPreset.cpp

@@ -42,6 +42,7 @@ dv::value ParticlesPreset::serialize() const {
     root["acceleration"] = dv::to_value(acceleration);
     root["explosion"] = dv::to_value(explosion);
     root["size"] = dv::to_value(size);
+    root["size_spread"] = sizeSpread;
     root["spawn_spread"] = dv::to_value(size);
     root["spawn_shape"] = to_string(spawnShape);
     root["random_sub_uv"] = randomSubUV;
@@ -67,6 +68,7 @@ void ParticlesPreset::deserialize(const dv::value& src) {
     if (src.has("size")) {
         dv::get_vec(src["size"], size);
     }
+    src.at("size_spread").get(sizeSpread);
     if (src.has("spawn_spread")) {
         dv::get_vec(src["spawn_spread"], spawnSpread);
     }

src/presets/ParticlesPreset.hpp

@@ -42,6 +42,8 @@ struct ParticlesPreset : public Serializable {
     glm::vec3 explosion {2.0f};
     /// @brief Particle size
     glm::vec3 size {0.1f};
+    /// @brief Particles size spread
+    float sizeSpread = 0.2f;
     /// @brief Spawn spread shape
     ParticleSpawnShape spawnShape = BALL;
     /// @brief Spawn spread